考虑非饱和渗流与增湿膨胀下的膨胀土隧道稳定性分析

发布时间：2018-06-02 02:40

本文选题：降雨入渗 + 非饱和渗流　；参考：《岩土力学》2017年11期

【摘要】：降雨入渗条件下,膨胀土的非饱和渗流与膨胀效应会降低隧道稳定性,研究两者对围岩变形与结构受力的影响非常必要。基于有限差分软件FLAC~(3D),根据其内置的渗流与温度场模块分别模拟降雨条件下的非饱和渗流过程与膨胀土增湿膨胀过程。通过编制相关FISH语言程序,考虑了膨胀土隧道非饱和渗流过程中基质吸力变化、土体软化和膨胀效应的影响。以某浅埋膨胀土隧道为工程背景,分析了降雨入渗时间、渗透与膨胀系数对膨胀土隧道围岩变形及支护结构受力的影响。结果表明:膨胀土隧道在降雨入渗过程中,围岩水平应力增大明显,而垂直应力变化不大;支护结构逐渐由竖向挤压变形转变为水平挤压变形;土体渗透和膨胀系数对支护结构受力影响很大,当渗透和膨胀系数增加到一定值后,衬砌弯矩显著增大,隧道安全性和稳定性大幅降低。
[Abstract]:Under the conditions of rainfall infiltration, the unsaturated seepage and expansion effect of expansive soil will reduce the stability of the tunnel. It is necessary to study the influence of the two factors on the deformation and structural stress of the surrounding rock. Based on the finite difference software FLAC~ (3D), the unsaturated seepage process and the humidification of the expansive soil under the conditions of the seepage and temperature field are simulated respectively. The effect of the change of matrix suction and the softening and swelling effect of soil in the unsaturated seepage process of expansive soil tunnel is considered by programming the related FISH language program. Taking a shallow buried expansive soil tunnel as the engineering background, the time of rainfall infiltration, the permeability and expansion coefficient on the deformation of the surrounding rock and the supporting structure of the expansive soil tunnel are analyzed. The results show that in the process of rainfall infiltration, the horizontal stress of the surrounding rock increases obviously, but the vertical stress changes little, the supporting structure gradually changes from the vertical extrusion to the horizontal extrusion, and the soil permeability and expansion coefficient have great influence on the stress of the supporting structure, and when the coefficient of permeability and expansion is increased to a certain value, the lining is built. The bending moment is significantly increased, and the safety and stability of the tunnel are greatly reduced.
【作者单位】：华中科技大学岩土与地下工程研究所;山西省交通科学研究院黄土地区公路建设与养护技术交通行业重点实验室;
【基金】：国家自然科学基金项目(No.51278216)~~
【分类号】：U451

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