狭长型基坑工程坑底抗隆起稳定性分析

针对狭长型基坑的特点，提出基坑坑底抗隆起稳定分析方法.对比常用的4种坑底抗隆起稳定分析方法及其异同点，结合2个实际工程进行相关算例的分析，指出在软弱土地基中规范要求的抗隆起稳定安全系数偏高；针对现有方法在狭长型基坑稳定分析中的局限性，提出考虑基坑宽度影响的坑底抗隆起稳定计算方法，分别探讨淤泥质土和粉土地基中基坑宽度、支护结构插入深度、开挖深度、土体抗剪强度指标和被动区加固等因素对狭长型基坑稳定性的影响.分析结果表明：采用该方法可以避免狭长型基坑中圆弧滑动面穿过对侧支护结构的问题，合理地考虑基坑宽度等因素对基坑稳定性的影响.
Abstract: A new method was proposed for basal stability analysis, according to the characteristics of slim deep excavation. Basic principles of four common methods of basal stability analysis were compared, and the calculating results of two projects showed that the required safety factor of basal stability in soft clay given by technical code was much higher. The calculating method which considered the effect of excavation width was proposed, due to the limitations of existing methods for basal stability analysis on slim excavation. The effects of some factors including the depth and width of excavation, embedded depth, soil parameters and passive reinforcement area on basal stability were analyzed under the ground of muddy soil and silt. Results show that the method proposed can avoid the across of sliding surface to the collateral supporting structure in slim excavation and reasonably consider the effects of the width factor, etc. on basal stability.