孔隙压力的类别及其叠加

Terzaghi 有效应力公式中的孔隙压力既指入渗引起的或外荷重引起的孔隙压力，也指两类孔隙压力之综合影响。入渗引起的孔隙压力由电拟试验确定，外荷重引起的孔隙压力起始值可用三轴试验测得。两类孔隙压力的叠加法则取决于孔隙压力的类别，产生的先后以及土类等。

Types and addition of pore pressure

The pore pressure in Terzaghi’s effective stress equation denotes the one caused by infiltration of water from the boundary of the soil mass or the one another induced by external load.In some cases it denotes the overall effects of these two types.The type of pore pressure,which the engineer chooses in the analysis,varies with the purpose of his analysis.The value of infiltration-induced pore pressure resolved upon the flow net is determined by the electric analog method,and that of external load-induced pore pressure is usually measured in triaxial tests as the initial value dissipating with time.The overall effects of the two types of pore pressure depend upon the type of pore pressure,order of their occurrence as well as the type of soils.