深部黏土渗透特性试验研究

龙固矿区深部黏土层由于深埋藏、高应力和固结时间长，所以其结构和物理力学性质与浅层黏土有所差异。为研究深部黏土的渗透特性，利用改装后的 SJ-1A.G 三轴剪力仪对龙固矿区第三系黏土进行室内渗透试验。首先研究了渗透系数与轴向应力的关系曲线，通过回归分析法拟合出渗透系数关于轴向应力的函数，总结了深部黏土和浅层黏土在回归系数上的差别；然后进一步研究了深部黏土渗透的各向异性和内在原因；最后得出渗透系数与轴向应变的关系曲线，深部黏土与浅层黏土的区别在于深部黏土没有小斜率延伸段。原因在于高应力下，浅层黏土明显屈服，发生塑性流变；深部黏土屈服不明显，而是发育微裂隙。该研究对深厚覆盖层矿井和深基坑防治水的设计有指导意义。

Experimental study on permeability of deep clay

The physical and mechanical properties of deep buried clays differ from those of shallow buried clays due to deep burial,high pressure and long solidification time.To study the permeability of the deep buried clays’,clay samples are taken from Longgu Coal Mine in Shandong Province,and their permeability is tested by using the SJ-1A.G triaxial shear equipment.Firstly,the curve which shows the relationship between coefficient of permeability and axial stress is studied,and a regression equation I was found to describe it.There are some differences of regression coefficients between deep buried clays and shallow buried clays.Secondly,the anisotropy of permeability and the internal reason of the deep buried clays are analyzed.Finally,the curve which shows the relationship between coefficient of permeability and axial strain is studied.The curve of the deep buried clays’ doesn’t have a segment stretched with little slope and this is because the shallow buried clays will yield under high pressure,while the deep buried clays will develop micro-crack.The study is of guiding significance for the waterproof design in thick covered mines and deep excavations