支护结构上水土压力计算微观分析

Micro-analysis of water pressure and earth pressure on support structure

以土体渗流为基础,通过对土颗粒间孔隙水状态的微观分析,结果表明:非粘性土的孔隙水是连通的,宜用水土分算方法计算水土压力;粘性土团粒间孔隙水的连通状态决定于团粒接触点附近渗透结合水膜的粘滞力和外界水力梯度的渗透力之间平衡状况;计算粘性土的水土压力时,微观分析认为,水土压力分算与合算是粘性土水土压力计算的最大和最小极限值。基坑几乎无渗流时,宜用水土合算方法计算。实例分析认为,存在渗流作用时,用水土分算方法计算水土压力偏于安全。

On basis of permeability test of soil, this paper discussed micro - scopically the state of inter - aggregate pore water. There are many conclusions. First, as the inter-aggregate pore water of non - cohesive soil is connected each other, water pressure and earth pressure are suitable to be calculated separately. Second, the state of inter-aggregate pore water of cohesive soil is determined by balanced condition between damping of bound water membrane and permeability pressure of hydraulic gradient. Third, maximum and minimum water pressure and earth pressure in cohesive soil are separately calculated by method of water-soil together and method of water-soil partly. Fourth, when there is no seepage flow, it is suitable to calculate water pressure and earth pressure by method of water-soil together. Fifth, if there is seepage flow, it is found safer to calculate water pressure and earth pressure by method of watersoil partly.