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房柱式及巷式矸石充填开采中,煤柱与矸石两两相隔,破碎矸石充填体处于侧限压缩状态,破碎矸石的密实程度、孔隙特征及渗透特性对于煤层瓦斯流动及地下水渗流的控制具有重要的价值。基于稳态渗透法及轴向位移控制法,利用一套自制的破碎岩体渗透试验系统,测定了破碎矸石在不同混合粒径下承压过程中的非Darcy流渗透特性,得到渗透特性(渗透率k和非Darcy流β因子)随孔隙率的变化规律。研究表明:1)雷诺数计算及孔压梯度与渗流速度关系曲线说明破碎矸石的渗透特征属于非Darcy流;2)孔隙率随着压缩位移的增加而减小,对于混合粒径试样,较小颗粒充填到较大颗粒的孔隙中,是使岩样的初始孔隙率减小的主要原因;3)在侧限压缩下,大颗粒受挤压破碎是产生0~2.5 mm粒径的原因,而渗流造成细小颗粒质量流失;4)侧限压缩下,渗透率总的趋势减小,而非Darcy流β因子增加,但在压缩过程中,渗透特性的变化趋势受颗粒粒径的影响会出现局部波折,说明破碎矸石的渗透特性与侧限压缩位移、颗粒粒径大小、压缩破碎、排列方式及孔隙结构(通道)有关。
In the column-column and lane-type waste rock filling and extraction, the coal pillars and the waste rock are separated from each other, and the crushed waste rock filling body is in a confined state, and the compactness of the broken waste rock, pore characteristics and permeability characteristics have the effects on controlling gas flow and groundwater seepage in the coal seam Important value. Based on the steady-state infiltration method and axial displacement control method, a set of self-made broken rock mass infiltration test system was used to determine the infiltration characteristics of non-Darcy flow during the confining pressure of the broken waste rock with different mixed particle sizes, and the infiltration characteristics Rate k and non-Darcy flow β factor) with the porosity changes. The results show that: 1) The Reynolds number calculation and the relationship between pore pressure gradient and seepage velocity show that the infiltration characteristics of broken waste rock belong to non-Darcy flow; 2) the porosity decreases with the increase of compressive displacement; Small particles filling the pores of larger particles is the main reason for the decrease of the initial porosity of the rock samples. 3) Under the confined compression, the large particles are crushed by extrusion, which is the reason of the particle size of 0-2.5 mm, While the seepage caused the mass loss of fine particles. 4) Under the confined compression, the general trend of permeability decreased, but non-Darcy flow β factor increased, but in the compression process, the change trend of permeability characteristics will be affected by the particle size Local twists and turns, indicating the infiltration characteristics of broken rock and lateral compression displacement, particle size, compression and fragmentation, arrangement and pore structure (channel).