圆砾层地区基坑围护选型及稳定性分项系数统计分析

圆砾层地区基坑工程具有很强的地域性,围护结构选型有待进行经验总结,并且土体强度等参数的不确定性使得基坑稳定性分项系数不能通过可靠度理论得到很好的解决。本文通过收集调研大量已成功实施的圆砾层地区基坑工程案例,整理围护结构选型相关参数,计算基坑稳定性分项系数,建立数据库。经统计分析,获取了圆砾层地区基坑围护结构合理选型规律,并采用取下限的方法给出了圆砾层地区基坑整体稳定性分项系数参考值为1.3,抗倾覆稳定性分项系数参考值为1.2,抗渗流稳定性分项系数参考值为1.5。

OPTION ASSESSMENT OF RETAINING STRUCTURES AND STATISTIC ANALYSIS OF STABILITY COEFFICIENTS FOR PIT EXCAVATION IN ROUND GRAVELS

The excavation engineering is very special in round gravel area. The experience of option assessment for supporting and retaining structures needs to be summarized. On the other hand, many parameters such as the strength index of soil are uncertain. The partial coefficients of excavation stability cant be solved well using the reliability theory. This paper investigates many successful excavation engineering examples located in round gravel area. It arranges those relative parameters of retaining structures form selection. It calculates the several main stability partial coefficients of these excavation examples respectively. It establishes a data base finally. After having analyzed this data base statistically, this paper discovers the law of excavation retaining structures form selection. It obtains the several main stability partial coefficients by the lower limit method. The result shows that the overall stability partial coefficient is 1.3.The resist-overturn partial coefficient is 1.2.And the resist-seepage partial coefficient is 1.5.