北山新场深部花岗岩三轴压缩力学特性试验研究

Experimental Study on Triaxial Compression Mechanical Properties of Beishan Xinchang Deep Granite

为研究北山新场深部花岗岩力学特性,文章以埋深550 m-560 m的花岗岩为试验对象,开展常规三轴压缩试验及同步进行的声发射试验,系统分析了岩石的强度、变形及声发射特征,并求取岩石物理力学参数。试验结果表明,在0.5 MPa-25 MPa范围内,花岗岩的弹性模量、泊松比随着围压的增大而增大,当围压大于15 MPa时,增加速率放缓;峰值抗压强度随围压的增大而增大,弹性阶段范围随围压的增大而扩大,表明围压的存在提高了花岗岩的刚度和强度;声发射参数曲线与常规三轴压缩轴向应变-偏应力试验曲线较为吻合,声发射信号都集中产生在应力-应变曲线的转折点,表征了岩石内部能量的释放和损伤的产生。

In order to study the mechanical properties of Beishan Xinchang deep granite,the conventional triaxial compression test and simultaneous acoustic emission test were carried out on granite with a buried depth of 550 m-560 m.The strength,deformation and acoustic emission characteristics of rock were systematically analyzed,and the physical and mechanical parameters of rock were obtained.The test results show that the elastic modulus and Poisson's ratio of granite increase with the increase of confining pressure in the range of 0.5 MPa-25 MPa,but the increase rate slows down when the confining pressure is greater than 15 MPa.The peak compressive strength increases with the increase of confining pressure,and the range of elastic stage expands with the increase of confining pressure,indicating that the existence of confining pressure improves the stiffness and strength of granite.The acoustic emission parameter curve is in good agreement with the conventional triaxial compression axial strain deviatoric stress test curve,and the acoustic emission signals are concentrated at the turning point of the stress-strain curve,indicating the release of energy and the generation of damage in the rock.