基于地层⁃注浆体⁃管片协同作用的海底盾构隧道受力研究∗

Stress Analysis of Subsea Shield Tunnel Based on Synergistic Effect of Stratum, Grouting and Lining Segment

摘要:

为研究海底盾构隧道中浆液与围岩及管片的相互作用特性，以厦门地铁 2 号线海底盾构段为工程背景，采用数值模拟方法和现场实测方法，分析注浆的浆液凝固过程，重点研究浆液的抗压强度、刚度、收缩、蠕变等特性对隧道力学和变形的影响特征，以及不同地层分布、不同隧道埋深下的管片受力特征，并采用流固耦合研究海水位变化对管片受力的影响。计算研究表明：注浆材料的刚度比 E₁/E₂₈对管片最终轴力和围岩压力影响小，变化幅度不超过 0.885%，对地层变形影响相对较大，可通过添加剂调节凝结时间，尽量让浆液早一些凝固硬化；最终收缩应变增大， 隧道内力和外侧压力降低，地层沉降增大，建议采用泌水率低的浆液，且其收缩值需控制在较小的范围内；蠕变参数取值对管片轴力影响较小，变化幅度最大不超过 1.35%；收缩参数主要考虑注浆材料后期的凝固收缩，蠕变则主要考虑注浆材料前期的蠕变收缩；地层变化及隧道埋深变化对隧道管片受力影响显著，隧道拱顶若软土较厚，则不易形成有效压力拱，导致围岩压力荷载较大；半日潮对地层变形、管片受力的影响不大，总体发展趋势与静水位条件下相似。最后，监测结果表明，数值模拟与实测的管片水土压力时程变化规律基本一致。

Abstract:

The interaction characteristics of cement paste with surrounding rock and lining segment in a subsea shield tunnel were studied by taking the subsea shield section of Xiamen Metro Line 2 as the engineering background. Numerical simulation and field measurement were carried out to analyze the solidification process of grouting slurry， focusing on the influence characteristics of compressive strength， stiffness， shrinkage and creep of cement paste on mechanical behavior and deformation of the tunnel， and the stress characteristics of the lining segment with different strata distribution and dif- ferent tunnel depths. Also， the influence of sea water level change on the stress of the lining segment was studied by the fluid-structure coupling technique. The calculation results show that the stiffness ra- tio E1/E28 of grouting material has less influence on the final axial force of the lining segment and the pressure of surrounding rock， producing a variation range of no more than 0.885%， while has a large influence on formation deformation. The setting time can be adjusted by additives to make the grout solidify and harden as early as possible； It is suggested that the grout with a low bleeding rate should be used， and its shrinkage value should be controlled in a small range； The creep parameters have lit- tle effect on the axial force，with a maximum variation range of less than 1.35； The shrinkage parame- ter mainly considers the solidification shrinkage of grouting material in the later stage， while creep pa- rameter mainly considers the creep shrinkage of grouting material in the earlier stage； If the soft soil is thick， the effective pressure arch is not easy to form， which leads to a large surrounding rock pres- sure； The semidiurnal tide has little effect on stratum deformation and segment stress， and the general development trend is similar to that under the static water level. Finally， the monitoring results show that the numerical simulated time history variation law of soil and water pressure in the segment is ba- sically consistent with the measured one.