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CHEN Guoxing, WU Qi, Charng Hsein JUANG
2025,45(6):1311-1370, DOI: 10.13409/j.cnki.jdpme.20250501002
Abstract:
Due to the uncertainties in seismic motions and storm waves, the diversity of liquefiable soils, and the complexity of sand liquefaction mechanisms, fundamental issues such as fundamental physico-mechanical mechanisms behind excess pore water pressure (ue) generation in a liquefiable soil, the collective effects of multifactorial interactions on ue generation, and liquefaction triggering criteria remain unclear. Based on decades of studies, Chen et al. proposed an invariance theory of sand liquefaction, incorporating invariant state thresholds and intrinsic laws governing cyclic behavior and solidliquid phase-transitions, which lead to a universal paradigm for site liquefaction evaluation rooted in invariant physical and mechanical correlations. This novel theory of sand liquefaction mainly includes the following four aspects. (1) For a liquefiable soil at a specific initial physical state, the threshold generalized shear strain is an intrinsic index that distinguishes nonlinear elastic and elastoplastic states, with a constant value. A power-law relationship is observed between cumulative dissipated energy per unit volume (Wc) and generalized shear strain amplitude (γga), reflecting the invariance in constitutive behavior. (2) The evolution of soil particle-fabric system governs ue generation in liquefiable soils through physico-mechanical mechanisms, with physical state changes serving as the intrinsic mechanism driving ue generation. Differences in ue generation rates under various cyclic loadings primarily stem from corresponding differences in shear strain rates. The marginal peak excess pore pressure ratio (ru,pm), marking the transition from a solid-liquid mixed phase to a transiently viscous fluid phase, exhibits dual invariance in mechanics and physics. A ru,pm value of 0.90 can be used as a liquefaction triggering criterion for soils both in laboratory element tests and field conditions. The relationship between USR (unit cyclic stress ratio) and Nclt (number of cycles required to trigger liquefaction defined by ru,pm =0.90) follows a negative power-law, thereby forming the threshold state line between the solid-liquid mixed phase and the liquid phase. This USR-Nclt curve depends solely on the initial state of the soil. (3) The equivalent skeleton void ratio (e * sk) serves as a single-variable proxy for the physical state of granular soils. For soils with fines particle content below a threshold, negative power-laws exist in the correlations between liquefaction resistance (CRR15 or URR15) in 15 cycles and e * sk, and between the stress-corrected shear-wave velocity (Vs1) and e * sk. Based on the principle of mapping transitivity, a unique correspondence between CRR15 and Vs1, i.e., liquefaction triggering curve, can be established through the index e * sk, indicating a novel and universal paradigm for site liquefaction potential evaluation. (4) The generalized shear strain serves as an equivalent shear strain (γeq) proxy for reflecting the 2D and 3D stress-strain state. A shear strain reversal at the irregular stress-strain loops of cycles in the Chen et al.'s generalized non-Masing, nonlinear, and hysteretic constitutive model of soil will occur when the incremental shear strain Δγeq=0. This strain reversal criterion is independent of the stressstrain hysteretic paths. The physical correlation between the maximum shear modulus and the extreme (maximum and minimum) void ratios exhibits an invariant mathematical form. Equivalent secant shear modulus and damping ratio across a wide strain range can be calculated through the shear stress/strain autocorrelation/cross-correlation functions, with algorithms invariant in mathematical form and physical mechanism. The physics-based model for the peak pore pressure increment (Δuep) demonstrates triple invariance in constitutive behavior, mathematical form, and cyclic loading conditions. A universal correlation links the peak pore pressure ratio (rup) to γga. The coupling of the Chen et al.'s non-Masing constitutive model and the Chen et al. 's Δuep model yields a novel effective stress-strain constitutive model of soil. Consequently, two novel universal site liquefaction potential evaluation methods are established: a total stress method (rup model-based) and an effective stress method (Δuep model-based). The invariance theory provides a unified basis for refining liquefaction mechanisms, improving evaluation methodologies, and advancing mitigation strategies in geotechnical earthquake engineering. The insights derived from decades of research, as reported in this study, will potentially enable the scientific and engineering communities to reinterpret the liquefaction mechanism, its evaluation paradigms, and liquefaction mitigation strategies.
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XU Jitao, ZHU Haitao, JIANG Mingjing, LI Wenhao, ZHANG Peiyao, LI Yuying
2025,45(6):1371-1382, DOI: 10.13409/j.cnki.jdpme.20250430046
Abstract:
Natural gas hydrates (NGH) existing in shallow deep-sea sediments are regarded as a novel clean energy carrier. During phase transition, NGH generates a small amount of water and a large volume of natural gas, which not only weakens the cementation between hydrates and soil particles but also generates excess pore pressure. Compared with the Nixon-Grozic modified model, a constitutive model further revised by incorporating gas compressibility parameters and a non-ideal gas equation of state produces excess pore pressure predictions that better reflect engineering practice. Additional seismic forces significantly affected the safety of hydrate-bearing slopes by altering the structural strength of the soil. Based on the infinite slope stochastic field theory, the positive promoting and negative restraining effects of pore pressure variations and vertical seismic action on slope instability probability were systematically analyzed. Using the second hydrate trial-production reservoir in the South China Sea as a case study, the safety factors of the submarine slope were calculated under three conditions: ignoring excess pore pressure, applying the Nixon-Grozic modified model, and implementing the nonideal gas modified model. The results indicated that as hydrate dissociation in the reservoir intensified, the slope safety factor declined progressively when excess pore pressure was not considered. When the Nixon-Grozic modified model and its non-ideal gas modified model were used for simulation, the slope safety factor demonstrated a non-monotonic trend of initially decreasing and then increasing, with predictions from the Nixon-Grozic modified model consistently lower than those from the non-ideal gas modified model. Notably, when the spatial variability of the reservoir's mechanical parameters was considered, probabilistic analysis revealed a significant increase in slope failure probabilities, indicating that hydrate dissociation severely compromised slope reliability.
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LI Jinke, LI Kang, LI Shengli, ZHAO Xuefeng
2025,45(6):1383-1396, DOI: 10.13409/j.cnki.jdpme.20250430095
Abstract:
To address the lack of measured structural vibration data during earthquakes, this study proposed a visual monitoring and verification method for building seismic responses based on virtual reality and computer vision. First, an indoor building model was constructed using Unreal Engine, and the seismic response time histories calculated by OpenSees were imported through the blueprint system to achieve nonlinear and coordinated deformation of structural components, thereby creating realistic seismic scenarios. Second, a deep learning model was employed to perform instance segmentation of walls, beams, slabs, and other components, followed by the extraction of edge line features. Then, the spatial geometric relationships of image edge points were established based on photogrammetric principles, and the three-dimensional displacements and inter-story drift angle time histories of the components were calculated. Considering the minor vibrations of actual surveillance cameras, the effects of translational motion, optical-axis displacement, and angular perturbation on the identified inter-story drift angle were further analyzed. The results showed that the inter-story drift angles identified by the proposed method were highly consistent with the inputs of Unreal Engine, with a maximum percentage error of only 0.28%. The translational jitter of the camera could be completely canceled out through inter-story differencing, while the effects of optical-axis motion and angular perturbation remained minimal. This study demonstrates that the proposed method can achieve low-cost validation of visual monitoring algorithms in a virtual environment and provide a feasible technical pathway for visual identification of seismic responses in real buildings.
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MENG Weiqing, YIN Chao, ZHENG Yongxiang, ZHAO Gaohui, WANG Wei
2025,45(6):1397-1410, DOI: 10.13409/j.cnki.jdpme.20250430033
Abstract:
In southwestern China, intense tectonic activity and frequent earthquakes occur, and slope instability and collapse triggered by earthquakes severely threaten the normal production and daily lives of residents. To more efficiently analyze the patterns of earthquake-induced slope instability and collapse, a continuous-discontinuous seismic slope calculation method was implemented for the first time in the general finite element software ABAQUS. The effectiveness of this method was validated through laboratory physical experiments and numerical tests. The analysis of the overall failure process of the Daguangbao landslide induced by the 2008 Wenchuan earthquake revealed that under 30 seconds of strong seismic action, the collapse of the Daguangbao landslide began at the rear edge of the slope top. The sliding surface of the landslide gradually became fully connected. After breaking through the constraints at the slope toe, the entire landslide slid along the sliding surface toward Huangdongzi gully, where it eventually deposited. Therefore, this method can provide a reference and basis for the calculation of earthquake-induced slope collapse.
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ZUO Hongpeng, WANG Bing, CHEN Peng, ZHANG Hongyan, WANG Li
2025,45(6):1411-1420, DOI: 10.13409/j.cnki.jdpme.20250430099
Abstract:
Given the time-varying characteristics of material parameters caused by complex environmental factors during the construction of continuous rigid-frame bridges, the traditional finite element analysis method is limited by the assumption of a single design parameter, and it is difficult to accurately simulate the actual changing state of the influencing parameters during the construction process, which leads to key technical problems such as insufficient alignment control accuracy during bridge construction. Therefore, this study proposed an intelligent prediction method for construction alignment of continuous rigid-frame bridges based on machine learning. First, parametric finite element modeling was used to simulate the construction deflection response under the coupling of multiple factors, and a complete deflection prediction sample database was constructed. On this basis, four construction-alignment prediction models based on support vector machine (SVM), random forest (RF), long short-term memory network (LSTM), and particle swarm optimization backpropagation neural network (PSO-BP) were established, and their prediction accuracy was compared and analyzed. The results showed that the prediction accuracy of RF and ELM models was relatively low. The LSTM model exhibited better prediction accuracy, with a maximum prediction error of 1.2 mm. The PSOBP model showed the best prediction performance. Its R2 values for the training set and the test set were 0.996 and 0.992, respectively. The absolute error of the predicted deflection was only 0.55 mm, and the relative error was less than 10%. The PSO-BP neural network enables accurate prediction of construction deflection, effectively improves the alignment control level of continuous rigid-frame bridge construction, and enhances the closure alignment accuracy of the bridge. The findings provide an important technical reference for the intelligent construction of bridge engineering.
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TIAN Chenghang, ZHAO Limeng, LI Yonggang, ZHANG Fangjian, ZHANG Wengang, SUN Weixin, DING Xuanming
2025,45(6):1421-1433, DOI: 10.13409/j.cnki.jdpme.20250430038
Abstract:
To address the challenges of low efficiency in traditional methods for tunnel water leakage detection and the large number of parameters and insufficient real-time performance of existing deep learning models, this study proposed a lightweight instance segmentation model based on an improved YOLOv8n-seg. The coordinate attention (CA) mechanism was introduced to enhance feature representation in target regions. The backbone network was replaced with MobileNetV4 to reduce computational complexity, and the EfficientHead segmentation head was incorporated to improve the efficiency of feature decoding. These improvements collectively enhanced both detection accuracy and inference speed in complex environments. The experiments were conducted on a tunnel water leakage dataset constructed using 3D laser scanning (including 3 140 enhanced images). Ablation experiments were employed to validate the effectiveness of each module. The CA mechanism increased the average precision (AP) by 0.82%, MobileNetV4 increased the AP to 81.21% while reducing the number of parameters by 43.2%, and the EfficientHead further optimized segmentation details. After joint improvements, the model achieved an AP of 83.21%, an F1-score of 78.53%, a number of parameters of 1.96M, and an inference speed of 355.2 FPS, representing a 6.6% increase over the original YOLOv8n-seg. Comparative experiments demonstrated that the proposed model significantly outperformed mainstream models such as Mask R-CNN in lightweight indicators (number of parameters and GFLOPs), while achieving accuracy comparable to that of two-stage methods, thereby meeting the real-time detection requirement for tunnel water leakage. This study provides an efficient and reliable lightweight solution for structural health monitoring in tunnels, offering practical value for engineering applications.
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2025,45(6):1434-1443, DOI: 10.13409/j.cnki.jdpme.20250430053
Abstract:
To reveal the influence of nonlinear characteristics of fault sites on the seismic response mechanism of cross-fault tunnels, the dynamic response of tunnel structures under the driving effect of site nonlinearity was systematically analyzed using shaking table model tests. The results indicated that the fault site exhibited a pronounced three-dimensional spatial response, where the reflection and refraction of seismic waves amplified high-frequency components and induced additional vibration components. Moreover, as seismic intensity increased, the site demonstrated nonlinear behavior, including shear modulus degradation and enhanced damping. The acceleration responses of the cross-fault tunnels were characterized by spatially heterogeneous distribution, with the most pronounced response concentrated at the fault interface zone, whose spectral characteristics were jointly controlled by site effects and seismic input. Tunnel damage was dominated by shear deformation, with deformation magnitudes in the fault zone significantly exceeding those of the surrounding rock, and the inter-segment differential deformation increasing nonlinearly with seismic intensity. Lining damage evolution exhibited strong spatial correlation, with cracks tending to propagate obliquely along the fault interface. Variations in structural dynamic properties effectively reflected the stiffness degradation process. These findings reveal the seismic damage mechanism of tunnels under nonlinear fault site effects, thereby providing a theoretical basis for the seismic design of cross-fault tunnels.
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GUO Wanli, SHEN Xin, ZHAO Yuchen, HUANG Han
2025,45(6):1444-1454, DOI: 10.13409/j.cnki.jdpme.20250430049
Abstract:
According to the characteristics of seasonal water supply and periodic temperature variations of canals in alpine regions, the external conditions of canals can be simplified as wet-dry-freeze-thaw coupling cycles by taking one year as a full cycle. A frost-heave model considering water-heat coupling and soil damage was employed to simulate the deformation process of heightened canals in alpine regions under wet-dry-freeze-thaw coupling cycles using the finite element method, with particular emphasis on the uncoordinated deformation characteristics between the new and old canal slopes. The results showed that uncoordinated deformation zones of the heightened canal under the wet-dry-freezethaw coupling cycles were concentrated near the heightening interface, mainly resulting from the uncoordinated frost-heave and thaw-settlement deformations of the canal slope during the freezing and thawing stages. With increasing wet-dry-freeze-thaw cycles, the saturated area below the seepage point of the canal slope gradually deepened and expanded, while the saturation of the canal top soil decreased, which intensified the uncoordinated frost heave between the canal top and slope. The uncoordinated deformation of the canal slope led to the formation of voids between the canal soil and lining. Based on the characteristics of these voids, the uncoordinated deformation patterns of heightened canals in alpine regions can be divided into three typical types: voids in the heightening layer, voids at the interface, and slope-lining bulging accompanied by voids in the heightening layer. When analyzing the uncoordinated deformation of the heightened canal in the alpine regions, it is recommended to adopt four points—the slope crest, the heightening interface, the slope midpoint, and the seepage point—as deformation control points, on the basis of which the void configuration and maximum void deformation of the heightened canal can be assessed.
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LU Zheng, WANG Zhijie, FU Jundong
2025,45(6):1455-1463, DOI: 10.13409/j.cnki.jdpme.20250430079
Abstract:
With the increasing diversity of functions and forms in urban architecture, higher demands have been placed on the performance and adaptability of structural dampers. This study proposed a Semi-active Particle Inerter System (SAPIS) based on a variable stiffness tuning strategy. By semi-actively adjusting the damper's stiffness, SAPIS effectively broadened the vibration control bandwidth and enhanced its vibration control performance. The proposed approach employed the Hilbert–Huang transform to identify the instantaneous vibration frequency of the primary structure. A trend-corrected spline-weighted exponential moving average method was further developed to predict the frequency variation trend. Based on the prediction, a fuzzy control strategy was constructed, categorizing the control output into three stiffness levels and allowing dynamic stiffness adjustment of SAPIS in response to varying excitation conditions. Numerical simulations were conducted using both sinusoidal signals and wind loads as external excitations to evaluate the vibration control performance of SAPIS for a cantilevered viewing platform. Under sinusoidal excitation, the results demonstrated that the proposed method accurately tracked the instantaneous frequency of the primary structure and dynamically adjusted SAPIS stiffness to maintain optimal tuning, thereby improving vibration control stability. Under wind excitation, SAPIS significantly reduced the peak and root-mean-square acceleration responses of the structure, with reduction rates of 51.79% and 48.11%, respectively. Compared with conventional Tuned Mass Damper (TMD) and Particle Inerter Systems (PIS), SAPIS exhibited superior vibration control performance. In addition, SAPIS shortened the damper stroke by 60.86% and 11.76% compared to TMD and PIS, respectively, further enhancing its applicability and feasibility in engineering practice.
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2025,45(6):1464-1474, DOI: 10.13409/j.cnki.jdpme.20250430064
Abstract:
To address the shortcomings of traditional seismic dampers, such as large residual deformation and low energy dissipation efficiency after strong earthquakes, a novel nickel-titanium shape memory alloy (NiTi-SMA) honeycomb sandwich damper was proposed. It adopted a three-layer composite structure. The core layer was a superelastic NiTi-SMA honeycomb plate to provide self-centering capability, the intermediate layer was filled with high-damping rubber or rubber-steel plate composite material for energy dissipation, and the outer layer was equipped with buckling-restrained steel plates to ensure stability. A refined numerical model was established using ABAQUS to investigate the effect of different filling material configurations on its mechanical properties. The results showed that filling with high-damping rubber could significantly improve energy dissipation capacity, and it synergistically exhibited excellent hysteretic performance with NiTi-SMA. Filling with steel plates could enhance bearing capacity and initial stiffness, whose volume was positively correlated with the damper's performance without affecting the self-centering property. Circular steel plates demonstrated higher energy dissipation efficiency than hexagonal ones, and variable wall thickness and fillet optimization could effectively alleviate stress concentration and improve fatigue performance. Through multi-material synergy and structural optimization, this novel damper balances self-centering and high energy dissipation characteristics, providing a new technical solution for seismic engineering.
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ZHANG Lingxin, ZHANG Lufeng, MA Jialu, CHEN Yongsheng
2025,45(6):1475-1484, DOI: 10.13409/j.cnki.jdpme.20250430066
Abstract:
The floor response spectrum is essential for the seismic design of non-structural components and can generally be obtained through time-history analysis or direct methods. However, time-history analysis is time-consuming and cannot meet the efficiency requirements during the preliminary engineering design phase. The commonly used direct methods can only consider the elastic stage when calculating the floor response spectrum and cannot accurately reflect the actual structure's elastoplastic behavior under seismic action. To address the above issues, widely used reinforced concrete (RC) frame structures in China were selected as the research object, and a three-dimensional refined finite element model was employed to conduct the elastoplastic floor response spectrum analysis. The effects of three key factors—floor height, damping ratio of non-structural components, and structural ductility coefficient—on the floor response spectrum results were investigated sequentially. Additionally, based on the Peter Fajfar method, an elastoplastic floor response spectrum direct method was developed, and a dynamic amplification factor formula applicable to RC frame structures in China was proposed. Finally, by comparing the floor response spectrum obtained by time-history analysis for a three-story frame structure, the proposed method in this study was verified to rapidly and accurately estimate the floor response spectrum of RC frame structures in China, thereby providing an efficient simplified method for the seismic design of non-structural components.
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LIU Chang, ZHANG Yang, ZHANG Jian, CHEN Haidong, ZENG Jie, ZHANG Yue
2025,45(6):1485-1492, DOI: 10.13409/j.cnki.jdpme.20250430027
Abstract:
Multifunctional massage chairs that are widely used in public buildings pose significant fire risks, making the study of their fire development patterns crucial for public safety. This study employed full-scale combustion tests and FDS numerical simulations to systematically analyze the fire development characteristics of individual and grouped chairs. The results showed that ordinary chairs exhibited a typical double-peak heat release rate (HRR) pattern, with peak values of 184.12 kW and 1 054.76 kW, respectively. The flame-retardant chairs demonstrated a peak HRR (PHRR) of 8 kW, representing a reduction of 99.24%. Numerical simulations further revealed that for grouped chairs with equal quantities, double-row arrangements increased fire magnitude by 46.58% compared to single-row arrangements. When ignition occurred at the central chair, the HRR reached maximum values. Shifting the ignition point toward the edges significantly reduced fire hazards under both arrangements.As chair quantity increased, PHRR under both arrangements showed a nonlinear pattern of initial increase followed by stabilization, ultimately reaching approximately 2 019.20 kW and 3 415.25 kW, respectively. Based on a point source radiation model with a critical thermal radiation threshold of 11.9 kW/m2, the critical safe distances under single-row and double-row arrangements should exceed 2.01 m and 2.62 m, respectively. This study recommends that flame-retardant products in public buildings should be prioritized, and single-row arrangements should be preferably adopted. For double-row arrangements, the size of a single chair group should not exceed 2×3 units.
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JI Tiantian, LIAO Luo, WU Shuanglan, NOZU Atsushi, NAGASAKA Yosuke, ZHANG Yi, CHEN Guoxing
2025,45(6):1493-1502, DOI: 10.13409/j.cnki.jdpme.20250430100
Abstract:
On August 24, 2016, a strong earthquake with a magnitude of Mw 6.2 occurred in the Amatrice region of Italy, with the epicenter located in the central Apennine Mountains. Despite the moderate magnitude, the shallow depth and complex fault rupture led to severe seismic damage. This study employed the Empirical Green's Function (EGF) method and inverted the source rupture process of the Amatrice earthquake, utilizing near-fault strong-motion data in the frequency range of 0.2~ 2.0 Hz. The results indicated that the area of maximum slip on the earthquake rupture was primarily concentrated in the shallow regions approximately 5 km to the northwest and 4 km to the southeast of the hypocenter, with a maximum slip of 1.5 m at a depth of 3.5 km. The inverted rupture velocity was 3.0 km/s. To validate the robustness and reliability of the proposed source model, sensitivity analyses of multiple EGF event combinations were performed, synthetic waveforms at strong-motion stations not used in the inversion were compared with their observed records (0.22.0 Hz), and comparisons with source models inverted from different frequency bands were conducted. The findings have significant academic and engineering implications for simulating ground motion induced by shallow earthquakes and for seismic design, especially in providing critical parameters for the seismic design of near-fault engineering structures.
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CHEN Bowei, XU Longjun, TIAN Hao
2025,45(6):1503-1514, DOI: 10.13409/j.cnki.jdpme.20250430021
Abstract:
This study aims to explore the characteristics and patterns of surface rupture–foundation– structure interaction caused by fault dislocation. Using the finite element software, a model of the soil and its upper building structure was established, taking into account the influence of the different orientation relationships between the structure and the location of the fault-induced surface rupture outcrop. The strain of soil, the bending moment of the foundation, and the stress distribution of the two-storey frame structure under the action of normal and reverse faults were calculated, and the influence of the presence of buildings located on the fault on the surface rupture morphology was analyzed. The results showed that the presence of buildings on the fault changed the development trend of rupture in the near-surface soil. Under the action of gravity, differences in compressive stress at the foundation bottom led to the variations in frictional resistance between the soil fracture surface and the foundation bottom surface, which restricted vertical deformation of the active side of the soil while inducing greater deformation on the passive side. These findings can provide references for the site selection of building structures in fault zones.
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LI Zhehan, XIAN Ganling, LAN Jingyan, LUO Chaorong, MO Hongyan
2025,45(6):1515-1524, DOI: 10.13409/j.cnki.jdpme.20250430055
Abstract:
To investigate the dynamic characteristics and cumulative deformation behavior of saturated soft clay under multi-level cyclic loading, a multi-level staged cyclic dynamic triaxial test was used to simulate the Foreshock-Mainshock-Aftershock sequential seismic loading. The effects of intermittent combined cyclic stress ratio, loading frequency, and the number of cycles to failure on the deformation and strength characteristics of saturated soft clay were studied and analyzed. On this basis, a mathematical model describing the development of cumulative plastic strain of soft clay under multi-level staged dynamic loading, incorporating multiple influencing factors, was proposed. The research results indicated that the dynamic strength of soft clay increased during the initial stage of dynamic loading due to vibration-induced compaction, while the structural damage during failure was intensified, leading to a reduction in residual strength. Under the influence of the mainshock-aftershock type cyclic stress ratio, the cumulative deformation of soft clay under multi-level staged dynamic loading exhibited three different patterns: stable, progressive, and failure types. Under the foreshock-mainshock type dynamic loading, the dynamic strength of soft clay decreased with increasing loading frequency, whereas under aftershock loading, it was jointly affected by both loading frequency and the number of cycles to failure. A deformation prediction model for soft clay, using the number of cycles to failure as the main fitting parameter, was established in this study. The model provides an engineering reference for evaluating the development of cumulative deformation and the stability of geomaterials under sequential seismic dynamic loading.
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LIU Mingwei, WANG Xiaolong, ZHU Jingjing, LIU Jiangang
2025,45(6):1525-1531, DOI: 10.13409/j.cnki.jdpme.20240921002
Abstract:
A temperature tracer testing method was proposed to accurately detect leakage defects at the joints of underground diaphragm walls in ultra-deep foundation pits. This method involved drilling holes immediately outside the joints of the underground diaphragm walls of the ultra-deep foundation pit to the same depth as the concrete underground diaphragm wall, and then measuring the groundwater temperatures at different depths inside the holes before and after pumping water from the foundation pit, to obtain the vertical distribution curve of groundwater temperature. Based on the standard vertical pattern of the temperature curve and its anomalies induced by leakage, the leakage depth at the joint was accurately determined. The leakage detection analysis results of the joints of the concrete underground diaphragm wall in two representative ultra-deep shield shaft foundation pits showed that the accurately identified leakage defect locations were directly and indirectly verified by both the excavation process and pumped-water volume of the foundation pit. The local changes in the vertical temperature curve of groundwater caused by leakage defects in the seepage-control structure of ultra-deep foundation pits are an important basis for determining the depth of leakage defects. Moreover, due to the very weak temperature changes at the leakage site, the resolution and stability of temperature logging instruments that capture weak temperature anomalies are crucial.
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WANG Hengzhi, ZHOU Yuchen, HE Yicheng, LU Yong, PAN Ying, ZHANG Min, ZHANG Yang, GONG Jie, LI Zhengkai, SUN Yejun, SUN Sicong, WANG Jun
2025,45(6):1532-1538, DOI: 10.13409/j.cnki.jdpme.20251228004
Abstract:
Based on offshore wind power projects, a comprehensive offshore seismic observation network was constructed in Jiangsu, integrating multiple disciplines, technologies, and methodologies, and covering seismometry, strong-motion monitoring, electromagnetism, and GNSS. Taking the records of the M6.6 earthquake in the offshore area of Yilan County, Taiwan, China as a case study, this study analyzed seismic records collected by various typical stations. The results showed that offshore wind power platform stations, seafloor stations, and DAS stations were all capable of capturing clear seismic records with distinct phases, enabling accurate identification of Pand S-wave arrival times. In particular, time-history and spectrum analyses of acceleration records from platform stations indicated that offshore wind power project structures exerted a significant amplification effect on ground motions, and could effectively reflect the dynamic response characteristics of the engineering structures under seismic action. The validity rate of real-time, high-sampling-rate seafloor electromagnetic observation data was steadily improving. Preliminary analysis of the observation data verified the feasibility of the offshore seismic observation technical scheme based on offshore wind power projects and the reliability of the observation data quality. This scheme expanded the coverage of Jiangsu Province's offshore seismic monitoring network and extended the scope of offshore seismic safety services, thereby laying a solid technical foundation for future research on the integration of on-site early warning and regional seismic early warning as well as structural safety assessment for offshore wind power facilities.
Volume 45,2025 Issue 6
专家特约稿
“第七届防灾减灾工程会议”专题
Rapid Report on Earthquake
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Study on Structural Health Assessment and Protection Strategies of Covered Bridges in Chongqing
HAN Zhaoyan, ZHANG Wengang, ZHANG Liangshuai, YANG Yang, LIU Yuanjian
Abstract:
As a composite carrier integrating transportation, architecture, and cultural heritage value, research on the protection of covered bridges is of great significance for the inheritance of traditional construction techniques. This paper systematically sorts out the development context and regional distribution characteristics of covered bridges at home and abroad. In response to the multiple risks faced by covered bridges, such as floods, strong winds, earthquakes, and fires, it summarizes the research progress of key technologies including structural reinforcement, intelligent fire prevention, and digital protection. Focusing on the Chongqing area, a comprehensive survey was conducted on 48 covered bridges, which cover three types: single-span wooden beam covered bridges, stone pier wooden beam covered bridges, and stone arch wooden covered bridges, with a concentrated distribution in the southeastern part of Chongqing. Among them, about 68% of the covered bridges are well-preserved, while the rest have problems such as stone deterioration, wood decay, and brick-tile diseases, with prominent issues of lacking fire-fighting and security facilities. Based on this, combined with the structural characteristics and regional cultural features of the covered bridges, protection strategies such as classified and graded protection, living inheritance of construction techniques, and integrated activation and utilization of cultural tourism are proposed. The research can provide a basis for the systematic protection of covered bridges in Chongqing and has reference value for the regional protection of similar cultural heritage.
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Prediction of Compressive Strength of Soil Solidified by Geopolymer Based Metakaolin in Cold Area
Chen Wengang, REN Huilin, HU Shuaijun*, HONG Yinzhe, LI Junfeng, KONG Gangqiang
Abstract:
In order to investigate the change rule and ratio design of compressive strength of polymer solidified soil at the base of calcium carbide slag-activated metakaolin in the seasonal frozen soil area, this study constructed a database using 180 sets of experimental data, including metakaolin content, calcium carbide slag content, curing temperature, curing time, andthe compressive strength of the solidified soil. The regression relationship between the input parameters and the output target (the compressive strength of the solidified soil) was established by various machine learning algorithms (KRR, ANN, and GPR) to predict the compressive strength of polymer solidified soil with calcium carbide-activated metakaolin base, and the performance of the model was evaluated by the coefficient of determination (R2), root-mean-square error (RMSE) and mean absolute error (MAE). Finally, the prediction results were interpreted by the parameters sensitivity analysis. The results show that the GPR model exhibits lesser prediction error and better prediction accuracy, and can better predict the compressive strength of polymer-solidified soils with calcium carbide-activated metakaolin base. The sensitivity analysis reveals that the effects of the curing temperature and curing time on the compressive strength are significant. The results of this study can provide a reference basis for the application design of the calcium carbide-activated metakaolin base polymer in the improvement of seasonal frozen soil engineering properties.
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The seismic response of cross- active fault tunnels: advances and prospects
BA Zhenning, WANG Yao, LI Dongqiao, LI Dongqiao, CHEN Su
Abstract:
Major tunnel projects crossing active faults inevitably face seismic risks. Under the coupling effect of strong earthquakes and fault dislocation-seismic motion, tunnel structures are vulnerable to severe damage or partial collapse, making their seismic fortification a key topic in earthquake engineering. This study first systematically reviews domestic and international research, compiling seismic damage cases and comparing structural responses under fault creep and stick-slip faulting. Subsequently, advances in physical model testing, analytical methods, and numerical simulations are summarized, along with existing fortification measures. Finally, key challenges in the seismic safety of tunnels crossing active faults are identified. The review highlights the limited understanding of the fault dislocation-seismic motion coupling mechanism and its influence on tunnel response. Future research should integrate seismology, geology, engineering and other scientific theories to clarify this mechanism, and develop fault dislocation-seismic motion coupling experimental techniques that can realize the synchronous input of fault dislocation and seismic ground motion. In addition,refined multi-scale numerical simulations should be developed to build numerical analysis models that can reflect the real structure and dynamic characteristics of the fracture zone, so as to improve thereliability of seismic performance evaluation and fortification design of cross-fault tunnels. The summary and analysis can provide reference for the seismic design of cross-fault tunnel.
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Detection of façade defects in high-rise buildings based on anomalous infrared thermographic region boundaries
FENG Xiaofei, LIU Xinan, Su Sheng, LI Bin, WANG Hesong, WU Leyuan
Abstract:
The building envelope is subject to a range of natural stresses, including temperature differences, precipitation, wind, vibration, and other environmental factors. These stresses, in combination with the continuous action of ageing, can lead to the formation of hollow drums, leakage, and other defects. These defects can ultimately result in the collapse of the building's wall brickwork, potentially endangering personal safety and property. In this paper, an innovative approach is proposed for the rapid detection of defects on the external wall of a building. The proposed method utilizes infrared thermal imaging technology to identify temperature anomalies in hollow drum defects. The study then proceeded to analyze the temperature distribution characteristics of different regions on the infrared thermal image of the building exterior wall under sunlight irradiation, as well as the boundary intrusion phenomenon in the temperature uniform region of the beam and column structure of the exterior wall and the infill wall in the presence of defects. The boundary pixel position of each temperature region was then extracted using the watershed algorithm, and a boundary pixel stacking folding map was established to identify the abnormal region. The efficacy of the proposed method in identifying and locating the intrusion and anomalous pixel points in the thermal image is demonstrated by a MATLAB-based image processing simulation. The paper also presents a rapid inspection and assessment scheme for the quality of urban high-rise building facades, which is designed using the example of Leixinjiayuan in Changsha Tianxin District.
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Development and evaluation of simulation methods for near-field ground motion: Development process and simulation results comparison based on complex physical processes
DANG Pengfei, YANG Hongfeng, CUI Jie, LIU Qifang
Abstract:
Ground motion simulation is a key component of earthquake engineering research. Ground motion simulation research will provide theoretical basis for post-disaster rescue and reconstruction, and has important engineering guidance significance for structural dynamic analysis and seismic design. It can also provide ideas for probabilistic seismic demand analysis of structures based on scenario earthquakes. The characteristics of near-field ground motion are mainly controlled by three factors, namely the source, the path and medium of seismic wave propagation, and local site conditions. Due to the complexity of seismic source characteristics, propagation paths, media, and site conditions, ground motion is unpredictable and nonreproducible. This study analyzes the development history of near-field ground motion simulation based on these three complex physical processes, briefly introduces the development history of commonly used numerical simulation methods for ground motion simulation, and discusses the advantages and disadvantages of each numerical simulation method. In addition, this study also summarizes the research progress and the simplified models used in engineering applications, and compares the seismic source models, energy, and simulation accuracy estimated by different methods. Finally, the limitations of the current research on ground motion simulation and future research needs were summarized. By continuously improving numerical simulation methods and combining advanced computing techniques and data analysis methods, the accuracy and reliability of earthquake ground motion simulation will be further enhanced, providing a more solid scientific foundation for earthquake-resistant design and earthquake risk assessment.
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Compression Performance and Engineering Application for Weatherproof Large-size Soilbags
WANG Zongjian, ZHOU Zheng, ZENG Yan, Naoki TATTA
Abstract:
Large-volume weatherproof soilbags are widely used in disaster relief and mitigation engineering. However, specific performance requirements and engineering standards for these applications have not yet ben clearly established. This study integrates engineering practices from both domestic and international sources to elaborate on various fundamental performance indices for this methodology. It identifies that the key performance controlling indicator for large-volume soilbags is the compressive property experienced by the lower bags under the weight ofupper bags. Compressive tests on soilbags filled with soils of three different densities were conducted to explore their compressive performance. Furthermore, based on the incremental generalized Hooke's law and considering the lateral non-linear deformation of the bags, a theoretical formula for the ultimate compresive strength of large-volume soilbags and a shear expansion equation for the soil within were derived. These equations are instrumental in calculating the failure load and settlement of the soilbags. The findings reveal that: (1) the primary factor controlling the failure of large-volume soilbags is the tensile strength of the mid-section fabric; (2) the theoretical value is basically consistent with the compresion test result. providing a reference for practical engineering applications; (3) a bulging degree coefficient m for the bags was proposed, which effectively reflects the degree of lateral expansion and serves as a significant engineering index for the side expansion of large volume soilbags; (4) after reinforcement with soilbags, the soil displayed more pronounced dilatancy and increased shear strength.
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Dynamic Incompatible Deformation and Failure Mechanism in A Long Deep Buried Fault-crossing Tunnel
WANG Yunxiao, ZHANG Cong1, WANG Hui, WANG Shanyong, LIU Jiayou, SHAO Tangsha
Abstract:
Dynamic problem of the long deep burial fault-crossing tunnel has always been a hot issue in deep underground engineering. It is the key to ensure the safety and stability of the tunnel after earthquakes post-disaster rescue. To explore the dynamic response of the surrounding rock of the long deep fault-crossing tunnel, relying on the Xianglushan tunnel project, the indoor shaking table tests and theoretical analysis were illustrated to explore the dynamic response of the tunnel surrounding rock under different inclination angles. Finally, the dynamic deformation and failure mechanism of the long deep buried tunnel were revealed, draw the conclusions: Under strong earthquake load, the dynamic response of the tunnel surrounding rock was the most significant when the inclination angle was 30°, and the peak acceleration, peak strain and peak displacement of the fault were the most intense. The dynamic response suggested the significant fault amplification and hanging wall effect by shaking table tests, which caused the incompatible deformation of the tunnel surrounding rock. This dynamic incompatible deformation caused the deformation and destruction of the long deep buried fault-crossing tunnel. The Xianglushan tunnel near-fault and cross fault locations was induced a cyclic back-and-forth tension, compression and dislocation by vibrational loads and residual tension-compressive stress. The longitudinal, transverse and annular cracks were produced to lead large deformation and even destruction. The research results can provide guidance and reference for the stability analysis and security assessment of the long deep buried tunnels in a strong seismic area.
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LIU Hanlong, REN Huiqi, CHEN Jun, ZHANG Wengang, LI Zhe, YIN Yueping, ZHANG Qin, WANG Luqi
2023,43(5):917-922, DOI: 10.13409/j.cnki.jdpme.20230921004
Abstract:
In the context of global climate change and increasingly active geological activities， China urgently needs to achieve rapid and efficient emergency response to natural disasters， and the corresponding upgrading of disaster prevention and control industries is also imperative. This study employs a comprehensive research methodology， encompassing literature review， on-site research， expert consultation， and questionnaire survey. Furthermore， combined with the development objectives of key steps within natural hazard mitigation， the issues and challenges faced by the natural disaster prevention and control industry were analyzed to propose the development paths of technology breakthroughs. On this basis， the following strategies were summarized. A more comprehensive standardization system should be established to seriously verify professional qualifications， control the market dynamics of industries in real-time， and ensure efficient competition in the industrial market. Leveraging advantages of localized development， the development of natural hazard prevention and control industries should be clustered to connect multiple chains. Led by the basic research on natural hazard prevention and reduction， the upgrading of natural hazard industries should be completed through theoretical innovation and technological iteration. Moreover， the industry should highlight the overall， systematic， and synergistic characteristics to enhance international competitiveness within disaster prevention and reduction. This paper aims to provide forward-looking， targeted， and evidence-based scientific references to facilitate the high-quality and expeditious development of the natural disaster prevention and control industry.
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WANG Jun, LIU Honggui, ZHOU Yuchen
2021(4):874-882, DOI: 10.13409/j.cnki.jdpme.202105007
Abstract:
This paper briefly reviews the development process of earthquake early warning and introduces the basic principles of earthquake early warning as well as the main determination methods for key parameters such as earthquake location，early warning magnitude and predicted intensity. As an effective means to mitigate earthquake disasters，earthquake early warning systems have been set up in many countries and regions of the world. Taking the system construction and application effectiveness as the breakthrough point，this paper introduces the main earthquake early warning systems in the world and the related progress in China. And then，based on the main challenges faced by the earthquake early warning，new and potentially innovative technologies and methods for future earthquake early warning system are prospected from the aspects of sensors，signal processing algorithms and networking modes.
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ZHOU Yun, CHEN Zhangyan, GUO Yangzhao, ZHANG Chao
2021(4):753-767, DOI: 10.13409/j.cnki.jdpme.2021.04.005
Abstract:
In order to improve the seismic performance of conventional infilled masonry wall，an innovative configuration named damped infilled wall/wallboard(DIW)was proposed by introducing the principle of viscoelastic damper. DIW has a simple construction，explicit working mechanism and independent intellectual property right. In this paper，the configuration and working mechanism of DIW was introduced. The material suitable for damping layer construction and its corresponding hysteretic performance were given. Seismic performance tests were carried out on DIW unit as well as plane frame structures with DIW. The in-plane working mechanism that the shear hysteretic deformation which is casued by relative movement between adjacent subpanel of DIW dissipates the input seismic energy was revealed. The double bracing macro-modelling method was proposed. The proposed model was used in the time-history analysis of a 3D frame structure with DIW. Results show that DIW is able to significantly reduce the influence on the dynamic characteristic and seismic performance of the main structures，and to protect the wall from suffering damages through decreasing the stiffness effect of wall/wallboard on structure. Out-of-plane performance of DIW was also studied by tests. The results reveal that the out-of-plane mechanism is the arching mechanism and the failure mode is fourhinge arching.The problems and directions that need to be further studied were given.
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PEI Zhenwei, NIAN Tingkai, WU Hao, ZHANG Yanjun, ZHANG Chaofeng, WANG Rui
2021(6):1382-1394, DOI: 10.13409/j.cnki.jdpme.20201130001
Abstract:
In China，landslide geological hazards with the characteristics of wide distribution and high frequency constantly pose serious threats to the safety of people's lives and property，and the construction and long-term operation of national key projects. In order to effectively mitigate the landslide disaster and maximize the benefit of disaster preventions，mitigations and relieves，it is urgent to develop more efficient emergency disposal technologies for landslide geological hazards. This paper systematically summarizes the state-of-the-art of emergency disposal technologies for landslide geological disasters，including emergency rescue technologies，emergency treatment technologies，emergency disposal technologies for special engineering，and emergency monitoring and warning technologies. Subsequently，the paper indicates the major problems at present and further development trends in the hope of promoting the rapid development and standardization of emergency disposal technologies for landslide geological disasters，and providing useful suggestions for disaster relief work.
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YANG Dongxu, YOU Yong, WANG Junchao, YANG Dong, LIU Jiankang
2020(6):841-851, DOI: 10.13409/j.cnki.jdpme.2020.06.001
Abstract:
The southeast region of Tibet is the largest marine glacier area in China. For investigating the physical and mechanical characteristics of glacial tills along the Sichuan-Tibet railway， and evaluating their stability as a geological hazard source and engineering foundation， 32 points of glacial tills in the Parlung Zangbo basin were taken as cases. A series of in-site and indoor tests on natural density， grain size analysis， large direct shear， triaxial shear， compressive strength， permeability coefficient and so on were carried out. Combining with field investigation methods such as sectional surveying and mapping， the distribution， morphological characteristics， physical and mechanical properties of glacial till and their correlation were analyzed. The result shows that physical and mechanical properties are closely related to moisture content， void ratio and clay content. The natural density and compression modulus are negatively linear related to the void ratio. The vertical permeability coefficient and the free expansion ratio show a quadratic relationship with clay content. The shear strength and compressive strength are binary relationship with void ratio and moisture content. Start-up patterns in three different deposit sites (modern glacier tongue， middle reaches of the valley， and the main river bank) were summarized， and the stability of the glacial tills was preliminarily discussed. The countermeasures for dealing with the glacial tills in Sichuan-Tibet railway and highway projects were suggested， such as passing by bridges or tunnels， engineering slope， and cutting or foundation， etc.
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LIU Hanlong, MA Yanbin, ZHANG Wengang
2021(4):710-722, DOI: 10.13409/j.cnki.jdpme.2021.04.002
Abstract:
In recent years，frequent geological disasters such as landslides，debris flows，and rock collapses，which are featured by severe harm and wide spread，threaten people’s lives and property safety，and restrict economic and social development and people’s desire for a better life. After years of technical research，mass prediction and disaster prevention，China has achieved remarkable success in geological disaster risk and hidden danger investigation. In order to improve the accuracy of national geological disaster survey and evaluation，comprehensive use of a series of new technical methods， such as synthetic aperture radar，high-resolution satellite remote sensing，unmanned aerial vehicle remote sensing and airborne lidar measurement，is underway. With the innovation and development of computer technology in the new era，the monitoring and early warning for geological disasters based on big data technology provide a new thinking paradigm and experience guidance for the prevention and control of geological disasters. For promoting an in-depth understanding of the new development direction in this field，key techniques in big data methods for acquisition，storage and analysis of geological disaster information are introduced，and progress on geological disasters analysis and prevention by worldwide scholars using big data techniques are reviewed.
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ZHANG Lei, SHI Bin, WEI Guangqing
2020(5):698-705, DOI: 10.13409/j.cnki.jdpme.2020.05.003
Abstract:
Among other factors,artificial slope cutting is one of the most common triggering factors oflandslide. In this paper,a series of model tests and numerical simulation have been conducted to investigate the failure mechanism and evolution process of the slope under slope cutting. As the coupling between sensing cables and soil directly affects the accuracy of monitoring results. Firstly,a new pullout apparatus is designed and the coupling deformation relationship between sensing cables and soil isacquired through pull-out tests under different confining pressures. According to the pull-out tests,asurcharge loading test model was designed. Strain-sensing cables that can capture the strains at different positions of the model slope were embedded in the soil mass. The measurement data of the cutslope were analyzed. It can be found that an abnormal strain-field area obtained by horizontal and vertical sensors coordinated with the location of the potential slip surface. This is verified by a comparisonbetween the measurements of the cables and numerical simulation results. Based on the BOTDA data,an empirical relationship is explored between the horizontal characteristic maximum strain and thesafety factor to estimate the slope stability condition and perform early-warning of landslide under theaction of slope cutting. The conclusions drawn in this study are of great significance to stability evaluation of artificial cut slopes.
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FU Xianwen, LIU Jinchun, SUN Ni, SHA Haiyang
2023,43(5):1076-1083, DOI: 10.13409/j.cnki.jdpme.20220228003
Abstract:
In order to explore the impact mechanical properties of 6061-T6 aluminum alloy and its application prospects in protective structures， the method of combining experiments and numerical simulations was used to carry out analysis and research. Based on multiple sets of quasi-static compression and impact compression experimental data， the corresponding parameters of the Johnson-Cook constitutive model were fitted； Conduct further numerical simulation analysis and compare the results of the numerical simulation with the experimental results. Finally， the yield strength， peak stress and other mechanical parameters of 6061-T6 aluminum alloy at room temperature are obtained. The corresponding parameters of the J-C model of 6061-T6 aluminum alloy are fitted； The results show that 6061-T6 aluminum alloy is a strain rate-sensitive material. Its yield strength and flow stress peak increase with the increase in strain rate， and the energy absorption to the impact load is also increases； When the strain rate is 1 600 s-1 ， the yield strength and ultimate bearing capacity increase by 30% and 78%， respectively， compared with the quasi-static state； The numerical simulation results are in good agreement with the experimental results， indicating that the fitted J-C model can better represent the stress flow behavior of 6061-T6 aluminum alloy at high strain rates. The research results can provide a basis and reference for the impact dynamic analysis of 6061-T6 aluminum alloy and its application in anti-explosion structure. It has broad application prospects in the fields of protection engineering， disaster prevention， and reduction engineering.
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ZHEN Yiwei, LIU Shuguang, ZHONG Guihui, ZHOU Zhengzheng, FANG Qi, ZHENG Weiqiang, LIANG Jiyu
2022(1):1-11,23, DOI: 10.13409/j.cnki.jdpme.20210416004
Abstract:
Due to the strong surface disturbance caused by the "5.12" Wenchuan earthquake，mountain torrent disasters have occurred frequently in Wenchuan County in recent years，causing serious damage to local houses. In Wenchuan County，two mountain torrent disasters，"8.20" and "8.17"，occurred in 2019 and 2020. Taking some of the damaged village buildings in the two disasters as research objects，this paper summarized the damage characteristics of different structural types of buildings，the spatial variability of the damage degree of buildings along the river and the building masking effect，as well as the damage modes of impact，scouring，siltation and immersion through disaster data mining and typical case analysis. Based on the research and analysis，this paper improved the existing building damage grading criteria by combining the characteristics of mountain torrent damage，and then proposed the classification of mountain torrent damage to rural buildings. Applying random forest algorithm and statistical analysis methods，the main influencing factors of building flood damage and their relationships were comprehensively analyzed in terms of water depth exposure，site exposure，and physical vulnerability. Finally，based on the analysis of building damage，some suggestions were proposed to improve the flood mitigation capacity of buildings in mountainous villages. The research results lay the foundation for further research on the physical mechanism of building flood damage，and also provide references for flood prevention planning and disaster mitigation design of buildings in mountainous villages and towns.
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GAO Yufeng, DAI Denghui, ZHANG Ning
2021(4):734-752, DOI: 10.13409/j.cnki.jdpme.2021.04.004
Abstract:
Local irregular topographies have significant effects on seismic waves. Topographic features can cause scattering and diffraction of incoming seismic waves，resulting in amplifications and de-amplifications of earthquake ground motions. The problem is an interdisciplinary research topic of seismology，earthquake engineering and civil engineering. The canyon，a common topographic feature， can significantly modify the ground motions. A large number of infrastructures such as dams and bridges have been built in such sites. Thus，the effect of seismic amplification on the engineering facilities in the canyon sites cannot be ignored. The paper summarizes the research results on the topographic amplification effects of seismic wave in canyon sites，sums up the research methods in this field，and puts forward the prospect for the future development of this field，aiming to provide reference for relevant researchers.
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CHEN Dawei, WU Zhijian, LIANG Chao, ZHOU Hanxu
2022(1):24-33, DOI: 10.13409/j.cnki.jdpme.20201024001
Abstract:
On September 14，2019，a large loess landslide occurred in Tongwei County，Dingxi City， Gansu Province. Through on-site investigation of the loess landslide and drone aerial survey，the topography，geomorphology，hydrogeology and other conditions that gave birth to the landslide were ascertained，and the morphological characteristics，structural characteristics and movement patterns of the landslide body were studied in-depth，revealing the Tongwei landslide Disaster mechanism. The high-density electrical method is used to detect the stratum structure，thickness of the sliding body， groundwater distribution and spatial distribution of the landslide area. Combining the finite element method and Morgenstem-Price method to calculate the stability of the slope，the distribution of the maximum shear strain and the variation of slope stability with rainfall duration are obtained. The results show that：(1)the shape of the Tongwei landslide is a chair-like shape，which is divided into three typical failure areas，forming a large number of vertical ridges，and the thickness of the loess sliding is approximately 8~50 m；(2)the Tongwei landslide belongs to the "traction-push" type of bedding landslide，and the movement mode is "pull toe instability traction-hindered sliding in the middle partinstability shift in the rear part"；(3)the groundwater is mostly fissure karst water，and the geological structure is not obvious. The geological structure activities such as early earthquakes have a great influence on the stratum；(4)the stability of loess slope decreases continuously with rainfall duration，and the maximum shear strain region is mainly distributed in the middle and upper part of the slope，and develops from mudstone contact to slope surface；(5)rainfall is the most direct factor triggering the Tongwei landslide，and the development of gullies，river erosion and agricultural production activities are important disaster-generating conditions
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JIANG Haolin, ZHENG Jiangrong, HE Bin, BAO Haiying, DAI Xianpeng, SHAN Han, WANG Dawei
2021(4):909-916, DOI: 10.13409/j.cnki.jdpme.202107015
Abstract:
Jiangsu earthquake monitoring began with the establishment of Nanjing Beijige Seismic Station in 1930. Through the unremitting efforts，exploration and innovation of several generations of seismic workers，the ability and technical level of earthquake monitoring have made a great progress. Looking back on the development of Jiangsu earthquake monitoring system，we can find that it has developed from the operation of weicher seismograph in June 1932 into a multidisciplinary observation network covering the whole province including seismometry，geomagnetism，geoelectricity，deformation and fluid. Seismic monitoring has gone through a process from introducing foreign seismic instruments to completely independent research and development of devices，from analog observation to digital network observation，from manual waveform recognition to AI automatic recognition of seismic events. With the rapid development of science and technology in recent years，the continuous development of observation technology，and the innovation and updating of seismic observation equipments， rich seismic monitoring results have been achieved from the seismic observation network，precursor network and mobile monitoring network covering the whole province. A large number of obtained observation data have been widely used in earthquake quick report，earthquake prediction research， earthquake disaster prevention，earthquake emergency rescue and earthquake scientific research. It has provided a solid earthquake safety guarantee for the rapid economic and social development of Jiangsu. Things present are judged by things past.This paper reviews the development process of earthquake monitoring in Jiangsu，pays tribute to the efforts of the older generation of scientists. The development of earthquake monitoring science and technology is passing down from generation to generation， serving the high-quality development of the whole province，and writing a new development history of earthquake monitoring in Jiangsu.
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ZHOU Yang, QI Zhengxin, GUO Xun
2021(4):860-873, DOI: 10.13409/j.cnki.jdpme.202106030
Abstract:
Multi-storey RC frame has been applied widely because of its flexible layout and economic applicability. Due to the complex behavior of materials and influence on nonstructural components， there is still no generally rational method for predicting the seismic failure mode and evaluating the anti-collapse capacity of RC frame structures. In the past decades，based on the seismic analysis，model tests and FE simulation，massive amount of studies have been carried out to investigate the seismic failure mode and collapse mechanism of RC frame. This paper summarizes these studies from the following aspects：the failure mode and collapse mechanism，the yielding mechanism and the anti-collapse design theories. Furthermore，the latest research progress is presented，the existing problems are pointed out and the research trends are prospected.
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Yu Shengsheng, Zhang Xiyin, Chen Xingchong, Wang Yi, Wang Wanping
2021(1):181-192, DOI: 10.13409/j.cnki.jdpme.2021.01.022
Abstract:
The influence of site conditions on structural seismic damage has become a well-known fact. How to conduct quantitative analysis of site seismic response has become one of the urgent problems to be solved in seismic engineering. This paper gives a summary of the research status of the site conditions and the influence of ground motion input on the site seismic response and the analysis methods of the site seismic response. It is shown that site conditions and ground motion input have a significant impact on analytical results of site seismic response. However，there are still some problems：The effects of the frozen soil layer are not fully considered when the site seismic response analysis is carried out in the frozen soil areas；there is no reasonable ground motion model to describe the actual ground motion accurately；the influence law of incident angle of seismic wave on seismic response of site has not been clarified；the widely used equivalent linearization method cannot fully reflect the real motion state of soil mass under the action of ground motion，so its calculation results are not reasonable. Combined with the above problems，the further research contents are prospected，which provide reference for the future research of site seismic response analysis.
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YU Feng, ZHANG Chenrong, HUANG Maosong
2020(4):623-632, DOI: 10.13409/j.cnki.jdpme.2020.04.017
Abstract:
The monopile for offshore wind turbine sustains long-term cyclic load due to environment and scouring in the seabed. The long-term cyclic loading behavior of the pile foundation under scouring is an important problem in the design of monopile for an offshore wind turbine. Laboratory model tests were conducted to investigate the performance of a large diameter pile and a small diameter pile in sand subjected to scouring and long term lateral cyclic loadings, in which the influence of scour depth and cyclic loading amplitude on the long-term behavior of the two foundations was discussed. The test results show that the applied cyclic loading improves the post-cyclic capacity of single pile, especially for the small diameter pile. Scour leads to the reduction of post-cyclic capacity of single pile, the effect of which increases with the scour depth. Comparing with the large diameter pile, the increment of residual cumulative deformation of the small diameter pile is smaller in early cyclic loading stage. When the cycle number is larger than 1000 and the scouring depth is twice of the pile diameter, the development of the cumulative deformation of the small diameter pile approaches to be stable, while a further development of deformation appears in the large diameter pile. By bringing the scour affected capacity into the dimensionless cyclic loading amplitude parameters, the lateral cyclic cumulative displacement calculation model of the two kinds of piles under scouring is established, which is applicable to the prediction of long-term lateral cyclic cumulative deformation of single pile considering scouring.
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WU Peisong, WANG Jian, OU Jinping
2020(3):317-325, DOI: 10.13409/j.cnki.jdpme.2020.03.001
Abstract:
Superstructures of seismically isolated structure keep in elastic or slightly elastic-plastic range subjected to rare earthquakes, thereby protecting superstructure effectively. However, very-rare earthquakes may happen in design reference period due to uncertainty of earthquake intensity and character. On basis of “survive rare earthquakes by sustaining significant damage but without globally collapsing” design, horizontal deformation of isolation bearings and overturning resistance under very-rare earthquakes, performance and cost of seismically isolated structure based on “survive very-rare earthquakes” are worth researching. Dynamic responses of three seismically isolated structures with different heights are obtained from elastic-plastic time history analysis. Main failure modes of seismically isolated structures subjected to very-rare earthquakes are presented by comparing the responses such as inter-story drift ratios, horizontal displacements of isolation bearings and overturning moments. The results show that under very-rare earthquakes, horizontal displacements of isolation bearing in all three classic seismically isolated structures are excessive, while other two responses both meet the requirements. With isolation bearings increasing suitably, new structures can avoid destruction by deformation of isolation layer increasing and survive very-rare earthquakes, while isolation effectiveness reduce slightly. Reducing the aspect ratio of superstructure appropriately can control the overturning of whole structure especially high-rise structure subjected to very- rare earthquakes. Therefore, considering both safety and economy, it is an effective and economical way to increase the ultimate displacement of isolation bearing, appropriately reduce the aspect ratio of high-rise seismically isolated structures, and realize resistance ability of isolated buildings subjected to very-rare earthquake.
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LI Yang, XU Chengshun, DU Xiuli
2020(3):326-336, DOI: 10.13409/j.cnki.jdpme.2020.03.002
Abstract:
During the Kobe earthquake in Japan, different degrees of earthquake damage occurred on the subway underground structures. Only one zone of the standard section of Daikai station totally collapsed, while the other zones of Daikai station, its running tunnels and other subway underground structures did not have serious earthquake damage. In this paper, the earthquake damage responses of the standard section, central hall and running tunnel structure of Daikai station were analyzed based on nonlinear finite element analyses which can reasonably simulate the damage of underground structures. Numerical results indicate that different width of structural cross section and burial depth lead to different overlying earth pressure on the structures at the standard section, central hall section and running tunnel section. The different overlying earth pressure generated different axial compression ratio of the three structural columns. In addition, the three structures with different lateral racking stiffness had different degree of damage and stiffness degradation, and further led to different lateral racking deformation. Eventually, the columns of Daikai station standard section destroyed due to the excessive relative deformation under the high axial compression ratio, which caused the total collapse damage to the entire frame structure. On the contrary, the columns of central hall and running tunnel section have not destroyed because there were not excessive relative deformation under the lower axial compression ratio, which kept the bearing capacity of the entire frame structure.
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Bu Yifan, Chen Guoxing, Zhou Zhenglong, Wu Qi
2021(2):343-349, DOI: 10.13409/j.cnki.jdpme.20191017003
Abstract:
One of the key issues in the deformation behavior of soil is the measurement of dynamic shear modulus and damping ratio. In order to fundamentally understand the measurement of dynamic shear modulus and damping ratio，using the resonant column apparatus and the cyclic loading triaxial testing system made by GCTS，the resonant column and cyclic triaxial tests on the variation characteristics of the normalized shear modulus(G/Gmax)and damping ratio(λ)with increasing shear strain (γ)were performed. It revealed that the variation trends of G/Gmax and λ with increasing γ obtained from resonant column tests were consistent with those obtained through cyclic triaxial tests，and the consistency was independent of the depth and soil type. Moreover，the two test methods can be combined to obtain the G/Gmax and λ of soil with a strain range of 10?6 to 10?2，which can provide reasonable curves of the G/Gmax and λ for nonlinear analysis on seismic site response of major projects.
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ZHUO Weidong, WANG Zhijian, LIAO Liyun, CAI Zhehan, WANG Hongda
2020(4):483-489, DOI: 10.13409/j.cnki.jdpme.2020.04.001
Abstract:
To improve the seismic performances of bridges with very tall piers in high seismicity area, design concept of the bridge with very tall piers, which is composed mainly of concrete-filled steel tubular (CFST) columns and energy dissipating mild steel plates (EDMSP), is proposed based on the principle of earthquake restorable structures. Trial design of a bridge with the proposed innovative composite box section tall piers is carried out based on a typical continuous rigid frame highway bridge with tall RC box section piers. The static and seismic performances of the bridge according to fundamental loading combination and E2 level seismic action are analyzed respectively. The seismic performance of the designed bridge under E2 level seismic action is compared with the bridge with conventional RC box section piers. The results show that: (a) under fundamental loading combination, the bridge with innovative composite box section piers can well meet the requirements of structural strength and stability; (b) under E2 level seismic action, the conventional designed bridge experiences medium damage in the piers, while only the replaceable EDMSP elements of the innovative designed bridge undergo plastic deformation, indicating the innovative designed bridge is earthquake restorable; (c) the seismic displacement responses of the innovative designed bridge is significantly smaller than that of the conventional designed bridge under E2 level seismic action.
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LIU Guoyang, LI Junjie, KANG Fei
2020(5):679-689, DOI: 10.13409/j.cnki.jdpme.2020.05.001
Abstract:
A three-dimensional discontinuous deformation analysis(3D DDA)method was used tooutput the kinetic energy and motion trajectory of rolling blocks. Compared with the results of the existing laboratory experiment and numerical simulation method,the accuracy of the 3D DDA methodwas verified. By analyzing the influence of the rockfall platform on the kinetic energy,motion trajectory and movement law of blocks along rock slopes with different slope heights,slope angles and foldingpoint positions,the influence law of the rockfall platform on the block movement was studied. Finally,the rockfall slope with a complex slope shape at Lang village in Tibet was simulated,and the protective effect of the rockfall platform on rockfall disaster was analyzed. The results show that the rockfall platform can decrease the kinetic energy of the rolling block,change the block motion trajectory,and reduce the impact of the rolling block on the protection structure or the traffic line at the slope bottom. Meanwhile,the general laws including the block movement and the corresponding platform design width under different slope characteristics are given,and they provide a basis for the design ofrockfall platform.
