型钢-水泥土复合重力式挡墙协同工作的变形特性分析

Deformation Characteristics Analysis of Cooperative Work for Shaped Steel-reinforced Cement-soil Composite Retaining Wall

水泥土重力式挡墙内插H型钢作为基坑变形控制的一种手段。通过分析悬臂结构弹性支点变形计算方法,指出组合墙体自身抗弯刚度是关键的影响因素。而不同受力阶段型钢和水泥土协同工作的各自荷载的分担作用发生变化,抗弯刚度存在不确定性。为了研究复合重力式挡墙的变形特性,以上海软土地区某挖深5.4 m的基坑为工程实例,建立型钢--水泥土重力式挡墙三维模型进行数值模拟,发现复合结构开挖至坑底后最大位移出现在开挖面中部,较好地限制了顶部位移,且水泥土分担荷载的作用明显。进一步分析发现水泥土截面置换率控制在构造要求范围内较经济,型钢前排密布更为有利。

As a method to control deformation,shaped steel-reinforced cement-soil composite retaining wall could be used in excavation engineering.Based on the analysis of the calculation method for the deformation of the cantilever structure,it is pointed out that the bending stiffness of a composite wall is the key factor.However,the load sharing of the steel and cement-soil is varied with applied load,so the bending stiffness is uncertain under external load.To analyse the deformation characteristics of a composite retaining wall,a three-dimensional model was established for numerical simulation based on a case study of a 5.4 m deep excavation in Shanghai.It is found that the maximum displacement appeared in the middle of the structure,which limited the displacement at the top.Also,the cement-soil can share the load and contribute to the deformation control.It is economical to control the replacement ratio of the cement-soil within the requirements,and more favorable to densely arrange the front rows of H-shaped steel.