黄土铁路路堤滑坡破坏机制与防治技术研究∗

Research on the Failure Mechanism and Prevention Technology of Loess Railway Embankment Landslide

摘要:

2021 年7 月20 日，河南省遭遇极端暴雨，诱发大量路基水害。通过对路基水害开展现场调查，查明了水害发生区间内区域地形地貌及水文地质条件，提出了黄土路堤滑坡破坏模式，并结合数值模拟分析路堤滑坡的破坏机制。运用多次分段控制注浆钢花管的防治技术对路堤边坡进行整治，采用挖探调查、高密度电法的手段探究钢花管加固黄土路堤的注浆效果，并结合数值模拟分析注浆加固前后黄土路堤边坡的稳定性。研究结果表明：（1）路堤滑坡不同于路堤浅表层溜坍的坡面病害，是一种严重的坡体病害，常由于坡脚地形低洼，降水在路堤边坡坡脚或下部汇集，浸泡软化路堤边坡，引起边坡岩土抗剪强度不足导致滑坡；（2）数值模拟结果表明坡脚积水深度对路堤边坡的竖向应力场无明显影响，对积水侧边坡的水平应力场与位移场影响显著；随着积水深度增大，路堤边坡最大剪应变的最值增大，稳定系数减小；（3）挖探调查与高密度电法探测结果表明钢花管注浆技术在黄土地层劈裂注浆效果良好，黄土边坡内部孔隙被水泥浆体充填，隔绝了坡体内部的流水通道，抑制坡体内部受水侵蚀；（4）钢花管注浆加固后数值模拟结果表明，整治加固后路堤稳定性显著提升。研究成果为铁路系统工务部门的水害防治工作提供参考。

Abstract:

On July 20, 2021, Henan Province experienced an extreme rainstorm, triggering numeroussubgrade water damage incidents. Through on-site investigations of subgrade water damage, the regionaltopography, geomorphology, and hydrogeological conditions within the affected area were identified.A failure mode for loess embankment landslide was proposed, and the failure mechanism of theembankment landslide was analyzed through numerical simulations. The prevention technology of multiplesegmented control grouting with perforated steel pipes was used to stabilize the embankmentslope. Excavation investigations and high-density electrical methods were used to explore the grouting effectiveness of perforated steel pipes in reinforcing the loess embankment, and numerical simulationswere used to analyze the stability of the loess embankment slopes before and after grouting reinforcement.The research results indicate that: (1) Embankment landslides differ from superficial slope surfaceslides, often caused by low-lying terrain at the slope foot where precipitation accumulates at thefoot or lower part of the embankment slope, soaking and softening the embankment slope, resulting ininsufficient shear strength of the slope and causing landslides. (2) The numerical simulation results indicatethat the depth of accumulated water at the slope foot has no significant effect on the vertical stressfield of the embankment slope but significantly impacts the horizontal stress field and displacementfield of the side slope with accumulated water. As the depth of accumulated water increases, the maximumshear strain value of the embankment slope increases, and the stability coefficient decreases. (3)Excavation investigation and high-density electrical method results indicate that the perforated steelpipe grouting technology achieves good splitting grouting results in the loess strata, filling the internalpores of the loess slope with cement slurry, thereby isolating the internal water flow channels and suppressinginternal water erosion. (4) The numerical simulation results after the perforated steel pipegrouting reinforcement indicate that the stability of the embankment is significantly improved. The researchresults provide a reference for the railway system engineering department in water damage preventionand control work.