断层带不同含石率土石混合体渗流特性试验研究

Experimental study of seepage characteristics of soil-rock mixture with different rock contents in fault zone

将断层带现场取出的断层泥及断层角砾混合物制成含石率分别为20%、30%、40%、50%、60%和70%的土石混合体重塑试样,应用GDS饱和-非饱和三轴试验系统测试在不同围压加、卸载条件下土石混合体试样的渗透特性,研究不同含石率土石混合体试样在不同围压水平作用下渗透系数的变化规律。试验结果表明,(1)不同含石率土石混合体(SRM)试样的渗透系数均随围压的增加而减小,且在围压加载初期试样渗透系数的降低速度较快,在围压加载中后期试样渗透系数的降低速度相对减缓;(2)在围压加载和卸载阶段,不同围压水平下土石混合体试样的渗透系数随着含石率的升高,均呈现出先减小后增大的趋势,含石率40%试样的渗透系数最小,含石率70%试样的渗透系数最大;(3)在围压卸载阶段,土石混合体试样渗透系数的恢复程度随着含石率的升高而增大,含石率70%试样渗透系数的恢复率达到50.2%;(4)在围压加载和卸载阶段,随着含石率升高,土石混合体试样渗透系数对含石率变化的敏感系数均呈现出先减小后增大再减小的趋势,在含石率60%时,试样渗透系数对含石率变化的敏感性最强;(5)围压加载和卸载阶段土石混合体试样渗透系数与围压的关系均可用指数函数进行描述。

The mixture of fault gouge and rubble which taken out from fault zone is used to make the soil-rock mixture(SRM) sample with rock block proportions of 20%, 30%, 40%, 50%, 60% and 70% respectively, and using GDS triaxial test system to measure the seepage characteristics of SRM sample under the different loading and unloading confining pressures, to research the variation law of permeability coefficient of the SRM(soil-rock mixture) sample with different rock block proportions under different confining pressure levels. The test results show that:(1) The permeability coefficient of the SRM sample with different rock block proportions decreases as the pressure increases;and the decrease rate of permeability coefficient in the initial stage of confining pressure loading is obviously higher than in the semi-late period.(2) In the stage of confining pressure loading and unloading, the permeability coefficient of SRM sample at different confining pressure levels present a common trend that with the increase of rock block proportion;it decrease first then increase, the permeability coefficient of the sample with rock block proportion 40% is the smallest;70% is the largest.(3) In the stage of confining pressure unloading;the recovery degree of permeability coefficient of SRM sample is ascend with the increase of rock block proportion, and the recovery rate of SRM sample with rock block proportion 70% reached 50.2%.(4) In the stage of confining pressure loading and unloading;the sensitivity of the permeability coefficient of SRM sample to the rock block proportion showed a rule of decrease first, then increase and then decrease;and when rock block proportion reached 60%, the sensitivity is highest.(5) In the stage of confining pressure loading and unloading, the relationship between permeability coefficient and confining pressure can described by exponential function.