不同水压下的黏土孔压传递规律试验

Experimental study on pore pressure transmission law of clay under various water pressures

对于在不同固结压力下固结的黏土,当对其施加不同水压时,其中的孔压分布和传递规律是解决地下结构上的水压力大小、基础抗浮计算以及边坡稳定分析等岩土问题的关键。现利用研制的试验设备对黏土开展试验,进行渗流状态和静水状态下孔压传递规律分析。试验结果表明:不论是渗流状态,还是静水状态,黏土内各点孔压趋于稳定所需时间均随固结压力的增大而变长,即固结压力越大,孔压传递越慢;因水压引起的超静孔压,渗流状态下的黏土内各点孔压偏离线性分布,表明黏土中的孔隙水未完全与外部水形成水力联系;静水状态下的黏土内各点孔压传递与理论一致,呈线性分布,不过当水压小于固结压力时,土体内各点孔压会略小于理论水压值,但依然呈线性变化。

The distribution and transmission law of pore pressure of clay under various consolidation pressures and water pressures was the key to solve the geotechnical problems, such as the water pressure of underground structure, anti-floating calculation of foundation and slope stability analysis.The analysis of the pore pressure transmission in the seepage state and hydrostatic state of clay was conducted by the designed equipments.Experimental results showed that the stable time of pore pressure increased with the increase of consolidation pressure in both seepage state and hydrostatic state. In other words, the better consolidation of clay would slow down the process of pore pressure transmission. For the clay in seepage state, the value of pore pressure in clay deviated from a linear distribution due to the excess pore water pressure, which indicated that the hydraulic connection between the pore water of clay and external water was not fully established. For the clay in hydrostatic state, the distribution of pore pressure was linear, which is consistent with the theory. However, when the water pressure is less than the consolidation pressure, the value of pore pressure was slightly smaller than the theoretical value, but the distribution was still linear.