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针对软岩巷道吸水后围岩强度明显降低、影响工程稳定性的问题,利用自主设计的深部软岩吸附水测试装置,对辽宁铁法集团大强煤矿深部钙质页岩进行了有水压和无水压两种条件下的吸水实验,研究了软岩样品在不同水压条件下吸水量随时间的动态变化。实验结果表明,钙质页岩在深井有水压和无水压条件下吸水量均随时间增加而增大,吸水速率随时间增加而减小;吸水量随时间的动态变化曲线均可用幂函数进行拟合。双对数坐标中吸水量随时间变化曲线在有水压条件下呈直线型,无水压条件下呈上凸型或下凹型。通过对岩石样品矿物组成、微观结构(包括孔隙结构)等物理化学性质参数的测定分析,初步揭示了大强煤矿深部钙质页岩吸水特性的影响因素。在有水压条件下初期吸水速率受到孔隙体积的影响较大,有效孔隙体积(孔径大于0.2μm)较大的岩石样品吸水速率也较大;粘土矿物含量较小而有效孔隙体积较大的岩石样品的累积吸水量较大。在无水压条件下岩石样品的吸水量与黏土矿物的含量和离子交换容量正相关。
Aiming at the problem that the strength of surrounding rock after water absorption in soft rock roadway is significantly reduced and the stability of the project is affected, a deep soft rock adsorption water testing device designed by itself is used to measure the water content of deep calcareous shale in Dafeng Coal Mine of Liaoning Tiefa Group. Under no water pressure, the water absorption of the soft rock sample under different water pressure conditions was studied. The experimental results show that the water absorption of calcareous shale increases with the increase of time and the water absorption rate decreases with the increase of time under the conditions of water pressure and no water pressure in deep well. The dynamic curve of water absorption with time can be expressed by power function Fitting. The curve of water absorption with time in double logarithmic coordinates showed a straight line under the condition of water pressure and convex or concave under the condition of no water pressure. Through the analysis and determination of the physical and chemical properties such as the mineral composition and microstructure (including pore structure) of rock samples, the influencing factors on the water absorption characteristics of deep calcareous shale in the Dagiang coal mine are revealed. The initial water absorption rate under the condition of water pressure is greatly affected by the pore volume, and the water absorption rate of rock samples with larger effective pore volume (pore size larger than 0.2 μm) is also larger; rocks with smaller clay mineral content and larger effective pore volume Sample cumulative water absorption larger. The water absorption of rock samples under no water pressure is positively correlated with the clay mineral content and ion exchange capacity.