围压对大理岩力学特性影响的试验研究

Experimental study of mechanical performance of marble under confining pressure

在MTS815岩石力学试验系统对大理岩进行不同围压三轴压缩试验的基础上,分析研究在不同围压下大理岩的变形特性和强度特性.研究表明,大理岩在三向应力条件下具有明显塑性变形特征,随围压的升高,变形特性表现为塑性特征增强,弹性模量和泊松比增大,峰前扩容明显增大;强度特性表现为峰值强度和残余强度均随围压的增大而线性增大,残余强度对围压的敏感性高于峰值强度,残余内聚力大大低于峰值,残余内摩擦角与峰值非常接近.

Experiments are carried out to study the marble specimens under different confining pressures by the MTS 815 rock mechanics testing machine. The strength and deformation properties of marble specimens are studied based on the experimental results. The results show that marble has a positive property of plastic deformation, plastic characteristic. The Young＇s modulus and poisson ratio of the specimen increases with the confining pressure, dilatancy pre-peak increases evidently, which can be seen from the strength characteristics. This shows that the peak strength and residual strength presented linear increase with the confining pressure. What＇s more, the sensitivity of residual strength to the confining pressure is higher than that of peak strength. The residual cohesion is much lower than the peak strength and the residual angle of internal friction is very close to the peak friction angle.