深大坑中坑基坑围护结构离心模型试验研究

圆形地下连续墙作为一种受力合理的围护结构,由于空间"拱效应"的存在,作用在拱圈上的土压力主要在地下连续墙内自身平衡,地下连续墙的水平位移相对较小。基于某深大圆形基坑工程实际,采用离心模拟技术研究基坑开挖过程中基坑围护结构的水平位移和弯矩分布规律。分析表明,基坑地下连续墙最大水平位移为11.6mm,位于上部基坑的中下部,并且随着开挖深度增大,墙体位移逐渐增大且最大位移点不断下移。研究成果可为圆形基坑开挖和支护过程中围护结构的变形规律分析提供参考。

Centrifugal model test study on foundation pit retaining structure in large and deep pit

At present,the circular wall is used as a reasonable envelope structure. Due to the existence of the space "arch effect", the earth pressure acting on the arch ring is mainly balanced in the wall and the wall. The retaining structure is mainly subjected to the ring axial force, which can give full play to the characteristics of high compressive strength of concrete,so round the lateral displacement of the wall is rel-atively small. Based on the actual construction of a deep circular foundation pit, the distribution of earth pressure in foundation pit excavation and the horizontal displacement and bending moment distribution of ground and wall are studied by centrifugal simulation. The maximum horizontal displacement of the founda-tion wall is 23.6mm, which is located in the middle and lower part of the upper foundation pit, and with the excavation depth increasing, the wall displacement gradually increases and the maximum displacement point. The active earth pressure of the circular foundation pit is smaller than that of the flattened earth pressure,and it is nonlinear. The effect of the arching effect is obvious. With the excavation depth increas-ing, the depth and radius ratio of the excavation depth The pressure distribution has a significant effect. The research results provide a reference for the study of the distribution model of earth pressure and the analysis of deformation law.