不同应力状态下裂隙岩体水力劈裂试验研究

以水泥砂浆作为类岩石材料,采用水-固-热耦合试验系统、电液伺服万能试验机、动态数据采集分析系统以及自主设计研制的高压水密封装置分别进行了不同注入流量条件以及单轴压应力作用下裂隙岩体水力劈裂试验。研究结果表明:无轴向拉压作用下,注入流量越大,试样劈裂破坏历时越短,越容易发生劈裂破坏,且试样水力劈裂起裂水压与劈裂水压的比值Pini/PIc与注入流量呈线性关系;注入流量不变的情况下,垂直裂缝走向的轴向压应力对试样水力劈裂起抑制作用,平行裂缝走向的轴向压应力较小时(0.1~0.3 MPa)对砂浆试样水力劈裂起抑制作用,较大时(0.4~0.5 MPa)对砂浆试样水力劈裂起促进作用。

Hydraulic Splitting Test of Fractured Rock Mass under Different Stress Conditions

Cement mortar is used as rock-like material and hydraulic fracturing tests of fractured rock mass under different injection flow rate and uniaxial compressive stresses are carried out by using water-solid-thermal coupling test system,electro-hydraulic servo universal test machine,dynamic data acquisition and analysis system and self-designed high-pressure water sealing device.The results show that under the action of no axial tension and compression,the larger the injection flow rate is,the shorter the time of splitting failure is,and the easier the splitting failure occurs,and the ratio of hydraulic splitting initiation pressure to splitting pressure Pini/PIc is linear with the injection flow rate.Under the condition of constant injection flow rate,the axial compressive stress along the vertical fracture direction restrains the hydraulic splitting of the specimen,and the parallel splitting failure occurs.When the axial compressive stress along the crack direction is small(0.1~0.3 MPa),it restrains the hydraulic splitting of mortar samples,and when the fracture direction is large(0.4~0.5 MPa),it promotes the hydraulic splitting of mortar samples.