基坑抗隆起稳定安全系数实用计算分析与应用

总结基坑由于插入深度不足导致的坑底隆起破坏的两种形式,研究基坑抗隆起稳定安全系数Ks计算公式的适用性及局限性,指出常用公式的错误,给出考虑因素更多、更适用的修正公式,并对修正公式的敏感性进行分析。运用该修正公式及数值方法分析基坑变形与Ks值的关系,指出Ks值对控制基坑变形的意义;通过分析发现基坑变形在Ks小于某值时发生突变,证明基坑设计存在一个最优的插入比。给出考虑因素全面、计算简便、更能反映工程实际的Ks计算公式,并得到一些对工程具有指导意义的结论,可以在基坑设计、施工中应用。

PRACTICAL CALCULATION ANALYSIS AND APPLICATION OF SAFETY FACTOR OF HEAVE-RESISTANT STABILITY OF FOUNDATION PIT

Two types of heave-destruction of foundation pit induced by less inserting depth have been summed up;and then the formulas for safety factor of heave-resistant stability calculated through arc-sliding method have been researched.The applicability and localization of calculating formulas of safety factor of heave-resistant stability that are widely applied to design of foundation pits have been analyzed;and four modified formulas,which are more applicable and rational,have been presented.Sensitivity of the new formulas is analyzed.The relation between deformation of deep braced excavation and the value of Ks has been studied by finite element method,through which mutation of excavation deformations is found at some value of Ks.Based on the previous research,it is proven that the deep braced excavation has an optimum inserting ratio and that the formulas have are simple,convenient for application to design and construction of foundation pit.