变质量破碎岩体非线性渗流试验研究

Study on Nonlinear Seepage Test of Variable Mass of Broken Rock

为了更进一步研究陷落柱的突水机理,完善陷落柱突水的试验基础,通过自制的一套变质量破碎岩体渗流试验系统,对变质量破碎岩体非Darcy流渗透特性进行试验,并对破碎泥岩在渗流过程中质量流失量、孔隙度、渗透率、非Darcy流β因子及加速度系数的时变规律进行了研究。研究表明:泥岩试样在渗流过程中渗流形式发生了巨大的变化。在渗流开始时,流失质量迅速增加,引起试样内部孔隙结构变化,孔隙度增加,试样的渗透性能增强,试样压得越密实,质量流失量越多,孔隙度变化越快,渗透性能越强。质量流失量与渗透性是相互影响的,由于试验中质量流失具有时变性特征,渗透性能也具有时变性。最后,陷落柱突水过程可以描述为,在其底部承压水压力作用下,大量细小颗粒随水流一起迁移流失,引起柱体内孔隙度变大,渗透性加强,导致渗流剧变,引发突水。

In order to study water - inrush mechanism of collapse column and complete testing basis for water inrush of collapse column, a self - designed seepage testing system for variable mass of broken rock was used to testing the nonlinear seepage characters of variable mass of broken mudstone. The time - changed laws of losing weight, porosity, permeability, non - Darcy flow/3 factor of mudstone dur- ing the seepage process were researched. It shows that the seepage form of mudstone sample changed enormously during the seepage process ; at the beginning of seepage, the losing weight increased rapidly, which caused the interior pore structure changing, porosity in- creasing and the permeability quality enhancing; the denser of the broken mudstone compressed, the larger of the losing weight was ; the faster porosity of sample changed, the better of the permeability quality was ; the losing weight and permeability were interacted with each other; the losing weight in the test had time -changed character, as well as permeability parameters. Finally, the process of water in- rush of collapse column could be explained as follow, a large number of fine particles were lost with flow under confined ground water, which caused porosity increasing, permeability quality enhancing, and resulting in seepage great changing and water inrush.