冻结状态青藏粉质黏土的渗透系数测量研究

Measurement of hydraulic conductivity of Qinghai-Tibet Plateau silty clay under subfreezing temperatures

粉质黏土在青藏高原多年冻土地区广泛分布,为了充分认识其在冻结状态下的渗透性质,开展了一系列渗透试验测量了在-0.6℃~0.1℃条件下含水率为50%的青藏粉质黏土的渗透系数。结果显示:在高负温区间内,冻结粉质黏土的渗透系数处于8.22×10^(-11)~7.19×10^(-9) cm/s之间;另外,渗透系数与土温之间呈现出幂函数关系,土温越接近于0℃,渗透系数增大越快;冻土的渗透系数表现出随着未冻水体积含量的增加而快速增大的趋势。渗透性的存在可测意味着高温冻土在外荷载下会存在固结作用。

In order to cognize the permeable property of the frozen silty clay spreading widely in permafrost regions on the Qinghai-Tibet Plateau, a series of laboratory tests are conducted to measure the hydraulic conductivities of the frozen silty clays with moisture content of 50% at temperatures from-0.6 to 0.1oC. The results show that under the warm negative temperatures, the hydraulic conductivities of frozen silty clay are in the range of 8.22×10^（-11）~7.19×10^（-9） cm/s. In addition, the hydraulic conductivity has a power function relationship with the soil temperature, and it grows more rapidly as the temperature gets closer to 0 oC. And the hydraulic conductivity expresses a rapid increase tendency with the increasing volumetric content of unfrozen water. The existence and measurability of the permeability in frozen soils indicate that consolidation may occur in warm frozen soils under external loads.