渗流作用下土的压缩变形特性试验研究

    Experimental study on compression deformation characteristics of soils under seepage

    • 摘要: 为掌握地下水位下降和地下水渗流作用下土的压缩变形特性,利用Rowe固结仪设计了满足降水场地土的应力状态、符合水位下降和渗流条件应力路径的孔隙水压力控制压缩试验,选用地铁车站场地有代表性的粉砂、粉土与粉质黏土,开展了减小孔压模拟水位下降和施加孔压差模拟渗流作用的压缩试验。试验结果表明,在孔压差作用下3种土均产生压缩变形,且孔压差引起的土的压缩变形随着固结压力增大而减小,土的压缩系数与水力梯度之间有良好的线性关系。粉土在孔压差减小过程中土仍然呈现压缩变形的现象,说明地下水水位恢复时存在地面继续沉降的可能性。

       

      Abstract: To understand the compression deformation characteristics of soils influenced by groundwater level decline and seepage, the pore pressure-controlled compression tests satisfing the stress state of soil in dewatering site and the stress path of water level drop and seepage are designed by using the Rowe consolidation instrument. The representative fine sand, silty and silty clay from a subway station site are selected to carry out compression tests to simulate the groundwater level decline by reducing pore pressure and the seepage by applying pore pressure difference. The test results show that all the three types of soils exhibit compression deformation under the action of pore pressure difference, and the compression deformation of soils caused by the pore pressure difference decreases with the increasing consolidation pressure. There is a good linear relationship between the compression coefficient and hydraulic gradient of soils. The silt still shows the phenomenon of compression deformation when the pore pressure difference decreases, which indicates that there is the possibility of ground settlement when the groundwater level recovers. The compression deformation of soils caused by seepage should be considered as appropriate in engineering practice.

       

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