考虑非饱和土强度理论的水泥搅拌桩挡土墙结构稳定分析研究

采用非饱和土的强度理论推导了考虑挡土墙周围非饱和土基质吸力对水泥搅拌桩挡土墙支护结构稳定性状的影响的分析方法，初步探讨了饱和一非饱和土环境下水泥搅拌桩挡土墙支护结构的稳定安全系数变化规律．     

稳态渗流下非饱和土涵洞竖向土压力的迭代解与简化

为描述稳态渗流下不同类别非饱和土涵洞的竖向土压力变化,应用圆弧小主应力轨迹法和Mohr应力圆获得考虑土拱效应的滑移面土压力系数,继而基于非饱和土的有效应力强度公式与吸应力理论,由水平薄层单元的竖向力平衡分别建立稳态渗流下上埋式/沟埋式非饱和土涵洞竖向土压力的迭代解,给出应用步骤并开展对比验证与方法拓展,最后结合吸应力沿深度分布规律提出涵洞竖向土压力的简化实用公式。研究结果表明:涵洞竖向土压力迭代解能合理反映土体类别、水分蒸发、降雨入渗和土拱效应的综合影响,并得到文献现场实测和理论公式数据的正确性验证以及对非饱和土涵洞的适用性;涵洞竖向土压力实用公式可显式表达且精度良好,方便估算不同稳态渗流下涵洞主要荷载;砂土涵洞可忽略非饱和特性影响而按饱和土计算竖向土压力,粉土和黏土涵洞可简化吸应力沿深度为线性分布;上埋式涵洞土拱负效应使得竖向土压力增大,而沟埋式涵洞土拱正效应使得竖向土压力减小。     

Prediction and safety analysis of additional vertical stress within a shaft wall in an extra-thick alluvium

An alluvium with a sandy aquifer at the bottom, but lacking an effective impermeable layer between the sandy aquifer and bedrock is referred to as a special alluvial stratum. Impacted by the drainage of the aquifer due to mining activities, a shaft wall in this special alluvial stratum will be subject to a downward load by an additional vertical force which must be taken into consid-eration in the design of the shaft wall. The complexity of interaction between shaft wall and the surrounding walls makes it ex-tremely difficult to determine this additional vertical force. For a particular shaft wall in an extra-thick alluvium and assuming that the friction coefficient between shaft wall and stratum does not change with depth, an analysis of a numerical simulation of the stress within the shaft wall has been carried out. Growth and size of the additional vertical stress have been obtained, based on spe-cific values of the friction coefficient, the modulus of elasticity of the drainage layer and the thickness of the drainage layer. Subse-quently, the safety of shaft walls with different structural types was studied and a more suitable structural design, providing an im-portant basis for the design of shaft walls, is promoted.