不同渗透水压下完整泥页岩剪切-渗流特性研究

Shear-seepage properties of intact argillaceous shale under different injection water pressures

为了探索高压水力浸润带和消落带岩体在压剪荷载与流体入渗双因素耦合作用下剪切渗流特性的衍化规律,利用自主研发的一套新型岩石剪切-渗流耦合试验系统,对饱水泥页岩进行了常法向荷载条件下不同渗透水压的剪切-渗流耦合试验和剪切蠕变-渗流耦合试验。试验结果表明:(1)随着渗透水压力的增加,饱水泥页岩剪切强度峰值、法向变形峰值以及剪切蠕变破坏强度均有所下降,说明渗透水压力对岩样力学强度具有损伤效果。(2)在剪切-渗流耦合试验过程中,岩样剪应力与法向变形在线弹性变化的末期会出现明显的上下波动现象,并伴有水流流出,剪应力和法向变形的突变点在时间上具有一致性。(3)在剪切蠕变-渗流耦合试验过程中,水流渗出速率与渗透水压力大小呈正相关,随着剪切荷载施加等级的提高,岩样蠕变变形量增大,单位时间内累计渗出水量亦有所提升。

In order to explore the evolution law of the shear-seepage characteristics of the rock mass in the high pressure hydraulic infiltration zone and fluctuation zone under the coupling action of pressure shear load and fluid infiltration,a new shear-seepage coupling test and shear creep-seepage coupling test were performed on saturated argillaceous shale under different injection water pressures using a new rock shear-seepage coupling test system.The test results show that:1) With the increase of injection water pressure,the peak shear strength,peak normal deformation and shear creep failure strength of saturated argillaceous shale decrease,which indicates that injection water pressure has a degradation effect on the mechanical strength of rock samples.2) During the shear-seepage coupling test,the shear stress and normal deformation of the rock sample have obvious up and down fluctuations at the end of the linear elastic change,accompanied by the outflow of water.The sudden changes of shear stress and normal deformation have time-dependent consistency.3) During the shear creep-seepage coupling test,the seepage rate of water is positively correlated with the injection water pressure.With the increase of the applied level of shear load,the creep deformation of the rock sample is larger and the cumulative amount of seepage water per unit time also increases.