基于地层损失的盾构隧道土压力非线性解析方法

发布时间：2018-06-10 11:09

本文选题：盾构隧道 + 土压力　；参考：《中国公路学报》2017年08期

【摘要】：针对盾构隧道结构在层状不均匀地层中承受的土压力荷载问题,根据调用强度设计(MSD)原理考虑土体非线性硬化特征,并采用Peck公式对应的土体位移场模式,提出施工不排水条件下盾构隧道结构周围土压力与开挖致地层位移势能的平衡方程,建立改进的隧道结构土压力非线性计算模型,并得到隧道上覆土体为均匀地层和层状不均匀地层2种工况下土压力荷载与地层损失率之间的非线性相关关系。将该计算方法应用于上海地区地铁隧道的土压力荷载计算,详细分析了应力释放系数与地层损失率之间的非线性相关关系,对均匀地层条件下不同的隧道覆土深度、土体强度、土体卸载模量以及侧压力系数进行了参数分析,并对上覆双层地层条件下不同的地层相对刚度、地层相对强度以及双层地层的相对空间位置关系进行了参数分析。结果表明:隧道开挖导致的地层损失对土压力荷载的计算结果具有显著影响,地层应力释放系数随地层损失率的增长呈现较为明显的非线性特征;在均匀地层中,地层刚度对土压力-应力释放系数非线性曲线的影响较为显著;在层状不均匀地层中,地层相对厚度及地层相对位置对土压力-应力释放系数非线性曲线的影响同样十分显著。
[Abstract]:In view of the earth pressure load on shield tunnel structure in layered heterogeneous strata, the nonlinear hardening characteristics of soil are considered according to the principle of transfer strength design (MSD), and the displacement field model corresponding to Peck formula is adopted. The equilibrium equation between the earth pressure around the shield tunnel structure and the potential energy of the stratum displacement caused by excavation under the condition of undrained construction is proposed, and the improved nonlinear calculation model of the earth pressure of the tunnel structure is established. The nonlinear correlation between the soil pressure load and the loss rate of the stratum is obtained under the condition that the overlying soil is homogeneous and stratified inhomogeneous. This method is applied to the calculation of earth pressure load of subway tunnel in Shanghai area. The nonlinear correlation between stress release coefficient and formation loss rate is analyzed in detail. The unload modulus and lateral pressure coefficient of soil are analyzed, and the relative stiffness, relative strength and the relative spatial position of the double layer strata are analyzed. The results show that the formation loss caused by tunnel excavation has a significant influence on the calculation results of soil pressure load, and the increase of formation stress release coefficient shows obvious nonlinear characteristics in homogeneous strata. The influence of formation stiffness on the nonlinear curve of soil pressure-stress release coefficient is significant, and the influence of formation relative thickness and relative position on the nonlinear curve of soil pressure-stress release coefficient is also very significant in stratified inhomogeneous strata.
【作者单位】：同济大学岩土及地下工程教育部重点实验室;同济大学地下建筑与工程系;
【基金】：国家自然科学基金项目(51608380,51538009)
【分类号】：U455.43

【相似文献】