深基坑整体稳定性分析中的孔隙水压力问题

Pore Water Pressure in Stability Analysis of Deep Excavation

在深基坑开挖整体稳定性分析中，把孔隙水压力的计算分解成静水压力、动水压力和超静水压力三个部分。对于静水压力，指出了目前工程中简化计算方法所存在的问题，建议按渗流流网的水头梯度进行计算。对于基坑开挖卸载所引起的超静水压力，应根据坑内外土体的应力路径做三轴不排水剪试验确定。此外，对于基坑开挖采用总应力法分析时，应按卸载总应力强度指标计算。

In the stability analysis of deep excavation, the ground water pressure is divided into three parts,i. e.,hydrostatic pressure,seepage pressure and excessive pore water pressure. For the calculation of hydrostatic pressure,the errors of currently simplified methods used in practical engineering are pointed out,and a new method based on seepage analysis is proposed. The excessive pore water pressure induced by excavation should be determined by the undrained triaxial compression test according to the stress path of the soil in and out of foundation pit. Furthermore,the unloading shear strength parameters should be applied when using total stress method to analyse excavation problems.