基于强度折减法的深基坑桩锚联合支护稳定性分析

Analysis on Stability of Joint Pile-anchor Bracing for Deep Foundation Pit Based on Strength Reduction Method

运用FLAC软件为辅助平台,对深基坑整个开挖过程进行数值模拟。采用强度折减法分别计算出基坑在无支护、单独护坡桩和桩锚联合支护不同工序下基坑的安全系数。分析得出基坑施工过程中,护坡桩是控制土体位移、保证基坑临时稳定性的控制单元,预应力锚杆是控制基坑整体永久安全性的控制单元,进而对比得出强度折减法应用于分析基坑稳定性是可靠的,可为基坑设计、施工和验收提供参考。

Numerical simulation in relation to the whole excavation of deep foundation pit was conducted by the aid of FLAC software. With strength reduction method, the values of the foundation pit＇s safety factor under different cases, i. e. without support, with single slope-protection pile and with joint pile-anchor bracing, were calculated. It was found that, during the whole construction of foundation pit, the slope-protection pile is the unit controlling the soil mass displacement and ensuring the pit＇s temporary stability, and the prestressed anchor is the unit controlling the whole pit＇s permanent safety; and further found by comparison that strength reduction method is reliable when being used to analyze stability of foundation pit, which could be the reference in design, construction and acceptance of foundation pit.