框架逆作深基坑变形特性三维数值分析

对基坑的变形特性进行数值分析在基坑设计中至关重要。结合实际工程框架逆作法超大基坑,选用Z Soil数值分析软件建立了全框架基坑模型并进行了数值模拟。由于需要考虑连续墙和土体之间的接触问题,土体则采用能够反映土体硬化特性的Hardening-Soil模型。为了更深刻的认识框架逆作法基坑变形的规律,并为设计者提供更好的参考,对影响框架逆作法基坑变形的一些主要参数进行了系统研究,包括框架梁截面尺寸、框架梁水平支撑竖向间距以及围护桩桩径等。结果表明:改变框架梁水平支撑竖向间距对围护墙的最大侧移、地表最大沉降有较大影响。增大围护桩桩径或框架梁的截面尺寸可以在一定程度上减小围护墙体变形,但超过某一定值时,其减小变形的效果将大大降低。

3D Numerical analysis for the deformation characteristics in deep excavation by frame-top-down method

The finite element numerical analysis of deformation characteristic is the crucial factor in the design of deep excavation.A three-dimensional finite element numerical analysis based on based on the software of Z_Soil was adopted to analyze the deep excavation constructed by frame-top-down method in practical engineering which considers the interactions between soil and retaining wall,while the soil was simulated with the HS constitutive model which can reflect the hardening characteristic of soil.Furthermore in order to acquire the deformation ride of frame-top-down excavations and offer better references to the designers,a systematic research is carried out considering the effects of some key parameters which affect the deformation of frame-top-down excavations.The parameters include the sectional dimension of frame beam,the vertical distance between horizontal supports of frame beam,and the diameter of retaining piles.The results show that vertical distance between horizontal supports of frame beam has great influence on the maximum lateral displacement of retaining wall and the maximum surface settlement.To some extent,deformation of retaining wall decreases when sectional dimension of frame beam or retaining pile diameter increase,but such effect tends to be much less when the deformation is greater than a certain value.