非对称开挖基坑两道支撑围护结构解析解

Analytical solution of retaining structures with two-layer struting system under asymmetrical excavation

现有的基坑围护研究大多是针对对称基坑,而受建设的环境条件、地形条件以及主体结构设计方案等诸多因素影响和限制,都会导致基坑面临非对称开挖。本文基于传统等值梁法,根据基坑开挖过程中围护结构的位移,采用共同变形法对作用在浅侧围护结构上的土压力进行修正,进而推导出非对称开挖基坑两道支撑围护结构解析解。结合算例,从围护结构的土压力分布情况、围护结构的水平位移情况、围护结构插入比等方面验证该解析解的合理性。结果表明:相比于传统方法的解,运用该解析解计算出的围护结构能有效降低工程造价;在浅侧开挖深度不变、深侧开挖深度增大时,深侧对浅侧的挤压作用增大,浅侧围护结构的插入比增大。

Most of the existing research on foundation pit retaining structures focus on symmetrical excavation.However,asymmetrical excavation of the foundation pit is encountered due to various factors such as environmental conditions,terrain conditions,and main structural design schemes.This paper is based on the traditional equivalent beam method.According to the displacement of the retaining structure during the excavation of the foundation pit,the earth pressure acting on the retaining structure of the shallow excavation was modified by the common deformation method,and then the analytical solution of retaining structures with two-layer struting system for the asymmetrical excavation of the foundation pit was derived.The rationality of the analytical solution was demonstrated from the distribution of earth pressure on the retaining structures,the horizontal displacement and insertion ratio of the retaining structures.The results show that compared with the traditional equivalent beam method,the retaining structures designed by the analytical solution method can effectively save the project cost.When the shallow side excavation depth remains unchanged as the deep side excavation depth increases,the squeezing effect of the deep side on the shallow side increases,and the insertion ratio of the shallow side retaining structure increases.