闭合型地下连续墙基础竖向承载性能数值模拟

Numerical Simulation of Vertical Bearing Capacity of Closed Underground Diaphragm Wall

基于室内模型试验,就闭合型与单片地下连续墙基础在竖向承载性能上的差异进行了对比分析,并采用FLAC-3D软件进行数值分析来丰富室内模型试验,探讨了土体变形模量、密度、内聚力以及内摩擦角对闭合型地下连续墙竖向承载力的影响。结果表明:闭合型地下连续墙基础外侧摩阻力的发挥过程与单片地下连续墙基础大致相同,但由于土芯的存在,其内侧摩擦阻力发挥机理更复杂;闭合型与单片地下连续墙基础均可视为端承摩擦型基础;随着墙周土变形模量的增加,闭合型地下连续墙基础竖向位移显著减少,墙体轴力也减少;密度对闭合型地下连续墙基础沉降的影响不显著;内聚力对侧摩擦阻力的影响程度受地下连续墙和土体之间相对位移量的控制;只有闭合型地下连续墙基础的沉降量超过20 mm时,土体内摩擦角才对基础的竖向承载力有较大影响。

Based on the indoor test of model,the differences of vertical bearing capacity of closed and single underground diaphragm walls were discussed,the software FLAC-3D was used in numerical simulation in order to supply the indoor test of model,the influences of deformation modulus,density,cohesion and internal frictional angle on vertical bearing capacity of closed underground diaphragm walls were studied.The result showed that the mechanism of outside friction resistance in closed and single underground diaphragm walls were mostly the same,but the mechanism of inside friction resistance in closed underground diaphragm wall was more complex because of the existence of core;closed and single underground diaphragm walls could be considered as end support friction type;vertical displacement and wall axial force deceased significantly with the increase of deformation modulus in soil around the wall;the influence of density on sedimentation of closed underground diaphragm wall was not significant;effect of cohesion on lateral friction drag was controlled by relative displacement between the soils of underground diaphragm wall;internal frictional angle had considerable influence on the vertical bearing capacity of underground diaphragm wall only when the sedimentation of underground diaphragm wall was more than 20 mm.