基坑抗隆起稳定安全系数的算法对比分析

Comparative Study on Calculation of Safety Coefficients for Anti-heave Stability

摘要:

基坑隆起变形破坏是一种常见的基坑失稳形式。基坑隆起变形量监测存在一定困难，基坑坑底抗隆起稳定性分析主要是计算安全系数。目前基坑抗隆起稳定安全系数计算方法主要有极限平衡、极限分析和强度折减等方法。结合工程算例，采用上述3种算法进行基坑抗隆起稳定安全系数计算，对比分析了各种计算方法的适用性。结果表明，极限平衡传统算法忽略的工程因素较多，计算结果过于保守，通过修正可以提高适用性。极限分析与强度折减的计算结果较为准确，但极限分析的破坏模式和强度折减中基坑稳定临界状态容许隆起量仍需进一步研究。

Abstract:

Heave deformation and fracture are the common instability form of foundation pit, which is difficult to be monitored. Analysis on anti-heave stability is mainly for the calculation of safety coefficients. The main computing methods of safety coefficient of anti-heave stability include limit equilibrium, limit analysis and strength reduction. An engineering example is adopted in this paper, the above-mentioned methods are used to calculate safety coefficients for anti-heave stability, and the applicability of these 3 methods is comparatively analyzed. The results show that more engineering factors are ignored by traditional limit equilibrium algorithm with too conservative result, which can be modified to improve the applicability. The calculation results are more accurate by limit analysis and strength reduction methods, but further study is needed on failure mode of limit analysis and permitted upheaval value of foundation pit stability in critical state by strength reduction.