黏土在渗水压固结中的超静孔压消散试验研究

渗透力作用普遍存在于水库土石坝、黏土铺盖、土质边坡等岩土工程中,其诱发的固结分析是研究热点,但固结过程中的超静孔压测试试验较少。现采用研制的装置,对经固结压力固结的黏土试样进行逐级施加水压的固结渗透试验。试验结果表明,施加的水压会引起土体中的孔隙水压力增长,增加的孔压在固结过程中有部分转化为渗透力,使试样产生压缩变形并引起孔隙比和渗透系数减小,进而导致固结系数的变化,且不同位置处变化的幅度不同,试验现象上表现为固结过程中未消散的超静孔压测试值沿高度呈非对称、非线性分布,最大值在试样偏下位置。变系数法理论计算值验证了试样中各点固结系数互不相同的现象。

Experimental Study on Dissipation of Excess Pore Water Pressure in Clay under Seepage Pressure Consolidation

Seepage pressure is commonly found in geotechnical engineering such as earth dam of reservoir, clay blanket and soil slope. And the analysis of seepage-induced consolidation is a research hotspot. However, the tests on excess pore water pressure in course of seepage pressure consolidation are few. By means of the newly developed device, the consolidation and permeability tests of clay samples subjected to consolidation pressures are carried out under the condition of gradually loading hydraulic pressure. Results show that the applied hydraulic pressure cause the pore pressure in clay increase. The increased pore pressure is partly converted to seepage pressure which will compress soil sample during consolidation. The void ratio and permeability coefficient decrease with the increase of seepage pressure. Then the consolidation coefficient of clay changes correspondingly, and the amplitude of variation is different at different locations. It can be found that the measured value of the excess pore water pressure in course of consolidation is asymmetrical and nonlinear along the height. And the maximum value is located at the lower position. The theoretical calculation values of variable coefficient method verify the difference of consolidation coefficient at different positions of specimens.