三轴循环荷载下岩石的变形及阻尼特性试验研究

Experimental study about the deformation and damping characteristics of rock under triaxial cyclic loading

对取自露天矿边坡的粗粒辉长岩,在MTS815岩石力学试验系统上进行三轴循环荷载试验,研究在三轴循环荷载下粗粒辉长岩的变形及阻尼特征,探讨在相同围压下轴向循环荷载周次对粗粒辉长岩动弹性模量、阻尼比的影响,及其相互关系;并分析在相同轴向振动荷载作用下,围压对动弹性模量和动阻尼比的影响,以及相互之间的变化规律。结果表明:在相同的轴向振动荷载作用下,动弹性模量和动阻尼比随围压的增加而逐渐增加;在相同围压和轴向振动荷载的作用下,当围压为3 MPa和4 MPa时动弹性模量随振动次数的增加逐渐增加,围压为2 MPa时动弹性模量随振动次数的变化规律不明显。在相同围压和轴向振动荷载的作用下,动阻尼比与振动次数没有明显的变化规律;在相同轴向振动荷载和振动次数作用下,动阻尼比随围压的增加逐渐变大。

This paper implemented tri-axial cyclic loading test by using MTS815 rock mechanics experimental system on coarse-grained gabbros collected in opencast mines. Investigated the deformation and damping characteristics of coarse-grained gabbros under tri-axial cyclic loading and discussed the impacts of vibration times with the same confining pressure, cyclic loading and confining pressure values with the same axial vibration loading on coarse-grained gabbro dynamic elastic modulus and damping ratio respectively. The results indicate that under the same axial vibration loading, the coarse-grained gabbro dynamic elastic modulus and damping ratio increase with the increment of confining pressure. When the confining pressure and cyclic vibration loading are fixed, dynamic elastic modulus grows with the increasing of vibration times at 3 MPa and 4 MPa confining pressure and does not experience obvious variant when confining pressure decreases to 2 MPa and damping ratio does not change explicitly with the change of vibration times in the same condition. However, damping ratio increases with the growing of confining pressure under the same vibration loading and times.