泥岩全破坏过程中渗透特性试验研究

1.山西焦煤集团有限责任公司,山西 太原 030024; 2.中煤科工集团西安研究院有限公司 水文所,陕西 西安 710054

泥岩; 渗透性; 裂隙; 应力; 应变

Experimental study on the characteristics of permeability in the all failure process of mudstone
LIU De-wang1,LIU Yang2,ZHAO Chun-hu2

(1.Shanxi Coking Coal Group Co.,LTD,Taiyuan 030024,China; 2.Hydrogeology Research Institure,Xi'an Research Institute of China Coal Technology & Engineering Group Corp,Xi'an 710054,China)

permeability; crack; stress; strain

DOI: 10.13800/j.cnki.xakjdxxb.2015.0113

备注

为了研究某矿区泥岩的渗透特性,提高底板抵抗承压水能力,对指导进一步开展泥岩的阻水抗渗特性机理提供科学依据。采用理论分析与室内试验相结合的方法,通过对全应力-应变作用下泥岩试样的渗透率、应力、应变与关键点指标测试,揭示泥岩岩样泥岩试样的渗透特性以及应变对渗透率的影响规律。研究表明:干燥状态下泥岩试样强度较高,是良好的隔水层,但遇水软化后其抗压强度大幅度降低; 泥岩渗透率-应变曲线由低水平渗透段、裂隙导通渗透段和破坏后渗透段三段组成,泥岩的渗透率与应力状态关系密切,其渗透率的峰值往往滞后于应力应变峰值点,这由岩样介质本身的特性所决定; 泥岩渗透率-应变曲线峰值前变化规律反映了岩石的破碎程度,而峰值点后的渗透率水平反映了岩石残余应力下的渗透特性。总体上来看,为防止承压水突破泥岩隔水岩层,应加强底板泥岩采动破坏深度及承压水导升高度的现场监测,这为底板采动岩体断裂失稳和突水等灾害预测预报提供参考依据。

To study the permeability of mudstone in one mining area and improve the ability of bottom to resist the confined water,providing a scientific basis to guide further development of mudstone's permeability mechanism for preventing and resistancing water.Combining the methods of theoretical analysis and laboratory test,the mudstone samples of permeability,stress and strain,and the key indicators were tested under the effect of complete stress-strian,revealing the permeability of mudstone samples and the influence of strain on the permeability.Research shows that: mudstone sample has high strength under dry state,It is a good water-resisting layer,but the compressive strength substantial decreases because of the water softening; Mudstone permeability-strain curve is composed of three sections: low permeability,fracture conductivity penetration and damage after penetrating,the permeability of mudstone is closely related to stress state,the permeability of the peak often lag behind the peak stress and strain,these are determined by the characteristics of the sample itself; The variation of mudstone before the peak of permeability-strain curve reflected the broken degree of rock,and the penetration level after the peak point reflected the permeability of rock under the residual stress.Overall,in order to prevent the confined water from breaking the mudstone water-barrier rock,we should strengthen the backplane mudstone's mining depth and field monitoring of confined water mediating height.It provides a reference basis to predict the floor mining-induced fracture instability of rock mass and water inrush disaster.