下组煤底板岩层阻渗性实测研究

In-situ Test on Reduction Infiltration Characteristics of Rock Mass under the Lower Coal Group Floor

底板原位压渗试验能够获得丰富的反映底板岩层阻渗性的信息,本文介绍了杨村矿下组煤底板3个不同岩性结构测试段的原位压渗试验成果,基于压渗过程曲线分析讨论了测试岩层起始导渗的水压力和渗透系数、压裂导通状态的水压力和渗透系数、压渗过程的压渗流量和渗流阻力的变化与导渗状态的关联性,得到如下认识:构造扰动部位底板阻渗能力薄弱,具有低阻强渗特点;完整性较好的原状结构底板岩层阻渗性较强,不但起始导渗的水压条件较高,而且导渗状态表现为高阻弱渗特点;底板岩层的阻渗性与岩性的关联性不明显,主要受制于岩层的原始结构条件和裂隙性状;杨村煤矿下组煤底板厚层砂岩是很好的隔水层,具有良好的隔水效果.

The information which shows the impermeability of rock mass can be obtained by the insitu water injection tests. The experimental results of three test periods with different lithologies and structures under the lower coal group floor in Yangcun Coal Mine were introduced. The initial water pressures, fractured water pressure and their corresponding permeability coefficients were discussed, as well as the relevance between flow rate, seepage resistance and pressure- infiltration state. The results show that the resistance ability of structural disturbance floor is weak, and those positions exhibit the behaviour of low resistance and high permeability. The floor with better integrity and original state structure shows strong resistance ability with higher initial infiltration pressure, and it still has strong resistance ability in the pressure-infiltration state. The impermeability of rock mass is mainly controlled by its structure and fracture, but not by its lithology. The result also shows the thick sandstone under the lower coal group floor in Yangcun Coal Mine is an effective impermeable layer with a good preservation effect.