深厚软土区基坑悬浮式水泥土框架支护结构设计

以某深厚软土地区基坑支护为例,设计悬浮于软土中的水泥土框架作为基坑支护结构,兼顾解决软土基底的施工困难。在选择挡墙宽度、嵌固深度、坑内加固土体厚度等设计参数作为因素进行正交试验的基础上,完成基坑设计参数优选,可为类似基坑设计提供有益的参考。在深厚软土地区基坑支护工程中,利用坑底加固土与基坑侧壁重力式挡墙组合形成"悬浮"于软土层中的水泥土框架支护结构,能够有效控制基坑变形,保障施工过程中的基坑稳定。引入正交试验表安排基坑设计试算方案,可有效减少试算次数,提高基坑设计的效率。通过对试验结果进行方差分析可知,在深厚软土地区"悬浮式"水泥土框架支护结构中,坑底土体加固厚度对控制基坑的变形发挥极其重要的作用;其对墙顶水平位移、墙顶竖向位移和坑底隆起的贡献均超过80%。

Design of Suspended Cement-soil Framework Retaining StructureApplied in Foundation Pit of Deep Soft Regions

Based on one foundation pit support in deep soft soil region, the cement-soil framework suspended in the soft soil is designed as the foundation pit retaining structure. Through orthogonal test with factors of the width of retaining wall, the depth of embedding and the thickness of reinforced soil at the bottom pit, it can optimize the design parameters of foundation pit and solve the construction difficulties of soft soil foundation. This provide a reference for similar foundation pit design. In the foundation pit retaining engineering of deep soft soil region, the reinforced soil of pit bottom and the gravity wall of foundation pit sidewall form the retaining structure of cement-soil framework suspended in the soft soil layer. This structure can effectively control the deformation of foundation pit and ensure the stability of foundation pit during construction. The calculation scheme of foundation pit design by orthogonal test table can effectively reduce the number of trial calculation and improve the efficiency of foundation pit design. The variance of test results shows that the reinforcement thickness of bottom pit can reduce around 80% of the top wall horizontal displacement, the top wall vertical displacement and the bottom pit uplift, which plays a key role in controlling the deformation of foundation pit.