不同压力下的黏土渗流性状试验研究

在诸如固结、沉降、降水等涉及渗透系数的岩土工程计算中,土层的渗透系数通常由渗透试验或现场抽水试验获得;并被视为常量。实际上渗透系数会随着外界条件的改变而发生变化,尤其是低渗土体。现利用研制的试验设备,对弱透水性的黏土进行渗透试验。试验结果表明:低固结压力下土体的渗透系数随水压呈"S"型曲线变化;且变化幅度较大。高固结压力下低渗土体的渗透系数随水压基本呈线性变化,且变化幅度较小。另外,水压对低渗土体的孔压传递规律也有影响,低水压作用下的土体孔压传递呈非线性变化,而高水压作用下呈线性变化。

Experimental Study on Seepage Properties of Clay under Various Pressure

The permeability coefficient of soil is regarded as a constant in geotechnical computing, such as consolidation, settlement and precipitation, which can be obtained by permeability test or field pumping test (in real life). In fact,Sthe permeability coefficientSmay change under different external conditions,especially inSlow permeabilitySsoil. The research of clay was conducted by theSequipments designed forSpermeability test. The results shows that the permeability coefficient of soil varies as an "S" curve when the water pressure goes higher under a lower consolidation pressure, and the changing range is large. On the other side, coefficient varies linearly under a higher consolidation pressure, and the changing range is limited. Additionally, the water pressure may also influence the transfer law of pore pressure in low permeability soil, which means the transfer of pore pressure changes nonlinearly under lower water pressure while varies linearly under a higher water pressure.