Experimental Study of Permeability of Broken Rock Sampled from Strata Containing Faults
断层内破碎岩石渗透性的实验研究

Permeability of broken rock sampled from strata containing faults is one of important factors involved in seepage disaster in underground engineering. Using a special instrument for compacting broken rock and a rock mechanics servo experimental system MTS 815.02, permeability coefficient of broken limestone, broken sandstone and broken mudstone was tested, respectively. Relation curves among axial stress, grain size, rate of water flow and permeability coefficient were obtained. Results show that 1) permeability coefficient of broken rock is closely related to its compaction state and decreases with axial stress increase for above 3 kinds of broken rocks ; 2) under the same axial stress, permeability coefficient of broken rock with small grain size is smaller than that of broken rock with large grain size. Small fault has advantage of hydraulic conductivity therefore easily leads to water inrush due to its low compaction and filling; 3) permeability coefficient of broken rock decrease with the increasing of water flow rate, but the effect of water flow rate on permeability coefficient is not obvious; 4) under the same axial stress and with the same grain size, the permeability coefficient of broken mudstone is lower than that of both broken limestone and sandstone nearly 1~2 orders of magnitude. So the fault surrounded by solid rock has better permeability and hydraulic conductivity. Above results may provide reference for evaluating fault hydraulic conductivity in mining.