渗透各向异性土层中考虑挡墙厚度的基坑稳态渗流解析解  

Analytical Solution for Steady State Seepage in Foundation Pits in Permeable Anisotropic Soils Considering Retaining Wall Thickness

作　　者：余俊[1] 李东凯 和振 张志中 张鑫全 YU Jun;LI Dongkai;HE Zhen;ZHANG Zhizhong;ZHANG Xinquan(School of Civil Engineering,Central South University,Changsha 410075,China;General Contracting Branch of China Railway Urban Construction Group Co.,Ltd.,Changsha 410000,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中铁城建集团有限公司总承包分公司,湖南长沙410000

出　　处：《铁道学报》2024年第5期142-151,共10页Journal of the China Railway Society

基　　金：国家自然科学基金(52078496)。

摘　　要：本文对考虑厚度挡墙支护下渗透各向异性土层中基坑的二维稳态渗流进行了解析研究。根据对称性取基坑半截面,将周围土层划分为5个规则区域,采用坐标变换将渗透各向异性土层转换成等效各向同性土层,对各区域利用叠加法和分离变量法推导得到二维稳态渗流场、挡墙上水压力以及坑底出逸比降的显式解析解。对比保角变换和积分变换方法,本文解渗流场计算结果连续且无奇异点,且基坑水头和挡墙两侧水压力分布情况与数值软件分析一致性较好,说明本文解析解的正确性和优越性。本文解与不同计算方法得到的挡墙水压力结果对比分析发现,挡墙厚度d、竖直与水平向渗透系数比α对挡墙上水压力的影响不可忽略。分析α、d对挡墙底部水压力及出逸比降的影响,随着α和d的增大,基坑外侧挡墙底部水压力增大,基坑内侧挡墙底部水压力减小;随着α和d的逐渐减小,坑底出逸比降不断增大;当α和d较小时,考虑一维渗流情况得到的出逸比降安全性较低,且随着α和d的减小与本文解析解差距越来越大。An analytical study was conducted on the two-dimensional steady state seepage in a foundation pit in a permeable anisotropic soil layer considering the thickness of the retaining wall support.According to the symmetry,with the half section of the foundation pit taken,the surrounding soil layer was divided into five regular zones.The permeable anisotropic soil layer was transformed into an equivalent isotropic soil layer by using the coordinate transformation.For each zone,an explicit analytical solution for the two-dimensional steady state seepage field,the water pressure on the retaining wall and the exit gradient at the bottom of the pit was derived by using the superposition method and the method of separation of variables.Compared with the conformal mapping and integral transformation methods,the seepage field calculation results of the solution of this paper were continuous and singularity-free.The head distribution of the pit and the water pressure distribution on both sides of the retaining wall were in good agreement with the numerical analysis,showing the correctness and superiority of the analytical solution in this paper.The comparative analysis between the results of the wall water pressure calculation solved in this paper and those of retaining wall water pressure calculation obtained by different calculation methods shows that the influence of the thickness of the retaining wall d and the vertical to horizontal permeability coefficient ratioαon the water pressure on the retaining wall cannot be ignored.An analysis was made on the influence ofαand d of suspended retaining wall on the water pressure at the bottom of the retaining wall and the exit gradient.With the increase ofαand d,the water pressure at the bottom of the retaining wall outside the pit increases while the water pressure at the bottom of the retaining wall inside the pit decreases.With the decrease ofαand d,the exit gradient at the bottom of the pit increases continuously.Whenαand d are small,the safety of the calculated exit grad

关 键 词：二维稳态渗流 渗透各向异性 显式解析解 考虑厚度的挡墙 总水头分布 出逸比降 水压力 

分 类 号：U21[交通运输工程—道路与铁道工程]