考虑局部荷载的基坑抗隆起稳定性三维分析

针对目前基坑抗隆起稳定性计算方法不能考虑三维空间下局部地面荷载作用的问题,在圆弧滑动法的基础上,结合Boussinesq解,建立了可以考虑地面局部荷载的基坑三维抗隆起稳定性系数计算方法,并结合工程算例,分析了地面局部荷载不同作用位置及范围下基坑三维抗隆起稳定性系数的变化。结果表明:基坑长度小于60 m时,三维抗隆起稳定性系数明显大于二维计算结果,计算结果最大可相差60%以上;荷载作用位置及作用范围变化时,基坑三维抗隆起稳定系数变化复杂,且在滑裂体边界附近的荷载变化会导致基坑三维抗隆起稳定系数发生较明显的变化;距离基坑较远的地面荷载对基坑抗隆起稳定系数影响较小,计算时可适当简化。

Three-dimensional Analysis on Basal Stability Considering Local Ground Load

Aiming at the problem of local load in three-dimensional space could not be considered in the stability calculation of foundation pit,a three-dimensional method was established to calculate the safety factor with the consideration of local load of the ground,on the basis of arc slipping method and Boussinesq equations.The simulation and analysis for an engineering case shows that when pit length is less than 60m,the three-dimensional heave stability coefficient was significantly greater than the two-dimensional calculation results,which can differ by more than 60％;the change of stability coefficient is complex with the transformation of the position and function of the load.The load change near the sliding crack body will cause more significant changes of the stability coefficient occur;Ground load far from pit has little influence on stability coefficient of foundation pit,which can be simplified appropriately.