天津地区基坑底抗渗流稳定性验算分析

立足天津地区的基坑工程,在分析坑底某深度处有承压含水层及基坑侧壁有粉土、粉砂层时的底板破坏机理的基础上,利用塑性极限分析中的塑性铰接法,提出了一种计算抗承压水突涌临界厚度的方法;利用体积力法验算抗沉侧壁接触管涌中隔水帷幕插入基坑底以下的临界深度;并综合两者考虑,结合天津地质状况,验算渗流破坏中隔水底板的临界厚度。重点是综合考虑基坑平面的几何尺寸及基坑底板土层的剪力指标c、φ等对基坑底抗渗流稳定性的影响。

Checking Computation and Analysis of Anti-seepage Stability at Foundation Pit Bed in Tianjin Area

The article puts forward a method to calculate the anti-bearing water gushing critical thickness by the plastic hinge method in the plastic utmost analysis based on analyzing the bedplate destroying mechanism that there is the confined aquifer at a depth of pit bed and the silt and silty sand level at the side wall of pit according to a pit project in Tianjin Area, utilizes the volume force method to check and compute the critical thickness of waterproof curtain inserted into the below of pit bed in the anti-sinking sidewall contact piping, and checks and computes the critical thickness of waterproof bedplate in the seepage failure based on the geological status of Tianjin by comprehensively considering the both. The article focuses comprehensive consideration on the influence of geometrical dimension of pit plane andshear indexes and of pit bedplate soil layer on the anti-seepage stability of pit bed.