剪力键支护体系的构想及模型试验研究

Conception and model test of shear bond supporting system

针对深大基坑支护工程中存在的问题提出了一种新型的支护形式-剪力键支护体系,由竖直桩和斜向支撑的剪力键构成。通过模型试验,对剪力键组和单排悬臂桩组分别量测了不同开挖深度时的桩顶水平位移及桩身内力,同时进行了有限元的数值模拟。结果表明剪力键组的桩顶最大水平位移约为悬臂组的1/10,桩身最大弯矩值约为悬臂组的一半左右。剪力键支护体系具有更大的刚度,能够有效减小桩顶位移及桩身最大弯矩,且耗材相对较少,支护深度较大,占据空间较少,不影响主体地下室施工,可节约工期和成本,为深大基坑的支护提供了新的型式。

In this paper, a new type of support form-shear bond supporting system, which is composed of vertical and oblique piles, is put forward for deep and large foundation pit construction. Through model test, the horizontal displacement of pile top and internal force of pile body are measured at different excavation depths for shear bond group and single row cantilever pile group, respectively. Finite element numerical simulation is carried out at the same time. The results show that the maximum horizontal displacement of the pile top in shear bond group is about 1/10 of that in cantilever group, and the maximum bending moment of the pile in shear bond group is about half of that in cantilever group. Shear bond supporting system has greater stiffness, and it can effectively reduce the displacement of pile top and the maximum bending moment of pile body. It consumes less material, is able to support deeper excavation, and occupies less space, which will not hinder the construction of the main basement. Therefore, it can save time and cost, and provide a new idea for deep foundation pit supporting.