不同倾角煤岩组合体三轴力学特性的界面水压效应研究  

Research on the Effect of Interfacial Water Pressure on Triaxial Mechanical Properties of Coal-rock Combination with Different Inclination Angles

作　　者：高翔 梁卫国[1,2] 武鹏飞[1,2] 陈跃都[3] 李浩 曹孟涛 GAO Xiang;LIANG Weiguo;WU Pengfei;CHEN Yuedu;LI Hao;CAO Mengtao(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of In-situ Property-improving of Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Department of Civil Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]太原理工大学原位改性采矿教育部重点实验室,山西太原030024 [3]清华大学土木工程系,北京100084

出　　处：《矿业研究与开发》2021年第10期67-72,共6页Mining Research and Development

基　　金：青年科学基金项目(51904196);中国博士后科学基金资助项目(2019TQ0174,2019M660652).

摘　　要：为研究煤层气间接压裂工程中煤岩界面稳定性问题,进行了干燥与水饱和下15°、30°和45°三种倾角无黏结自由界面煤岩组合体的三轴压缩试验和不同界面水压下30°倾角煤岩组合体的三轴压缩试验,揭示了界面倾角和水压对煤岩组合体力学特性的影响机理。结果表明:无黏结界面煤岩组合体强度随界面倾角增大而减小,水饱和状态下,倾角由15°增加到45°时,三轴抗压强度由36.91 MPa减小到7.84 MPa,降幅达80%,组合体破坏形式由15°时煤体的劈裂破坏,转变为30°和45°时界面的剪切滑移破坏;水饱和状态对煤岩组合体强度有弱化作用,且随倾角增大而减小,倾角为15°时,强度由50.83 MPa降低至36.91 MPa,降幅为27%,倾角为45°时,强度由8.72 MPa降低至7.84 MPa,降幅为10%;煤岩组合体峰值强度和残余强度与界面水压呈负线性关系,随着界面水压从0增加到4 MPa,峰值强度从18.53 MPa降低至11.67 MPa,残余强度从13.35 MPa降低至8.84 MPa,煤岩组合体越容易产生剪切滑移。该研究对了解间接压裂煤层气开采工程中煤岩界面稳定性与裂纹扩展条件特征具有重要意义。In order to study the stability of the coal-rock interface in the indirect coal-bed methane fracturing project, triaxial compression tests of coal-rock combinations with unbonded free interface at three angles of 15°, 30° and 45° under dry and water saturated states were carried out, as well as triaxial compression tests of coal-rock combinations with 30° inclination angles under different interfacial water pressures. The tests reveals the influence mechanism of interfacial inclination angle and interfacial water pressure on the mechanical properties of coal-rock combinations. The results show that the strength of the coal-rock combinations with unbonded interface decreases with the increase of the interfacial inclination angle. Under water saturated state, when the inclination angle increases from 15° to 45°, the triaxial compressive strength decreases from 36.91 MPa to 7.84 MPa, a drop of 80%. And the failure mode of coal-rock combination changes from the splitting failure of the coal body at 15° to the shear slip failure of the interface at 30° and 45°. The saturated state has a weakening effect on the strength of coal-rock combination, and the effect decreases with the increase of the inclination angle. When the inclination angle is 15°, the strength decreases from 50.83 MPa to 36.91 MPa, a decrease of 27%, and when the inclination angle is 45°, the strength decreases from 8.72 MPa to 7.84 MPa, a decrease of 10%. The peak strength and residual strength of coal-rock combination have a negative linear relationship with the interfacial water pressure. As the interfacial water pressure increases from 0 to 4 MPa, the peak strength decreases from 18.53 MPa to 11.67 MPa, and the residual strength decreases from 13.35 MPa to 8.84 MPa, the coal-rock combination is more prone to shear slip. The study is of significance for interface stability and fracture propogation in CBM recovery engineering through indirect fracturing.

关 键 词：煤岩组合体 界面水压 力学特性 剪切滑移 

分 类 号：TD315[矿业工程—矿井建设]