不同卸荷速率下变质石英砂岩力学性质试验分析

为研究不同卸荷速率下岩石力学特性,以锦屏一级大奔流沟料场特高边坡变质石英细砂岩为例,开展不同卸荷速率和不同围压下的卸荷试验,得到了应力-应变曲线,重点分析了卸荷速率对应力-应变关系、破坏特征、破坏应力差、强度参数的影响规律.结果表明:卸荷作用对岩石脆性破坏特征明显;常规加载试验为压剪破坏,卸荷试验为张剪破坏;随着围压的降低,弹性模量不断降低,卸荷速率越快,非线性关系越明显;卸荷速率越快,泊松比增加越慢;卸荷条件下岩石的黏聚力减小,内摩擦角增大.

Mechanical Property Test at Different Unloading Velocities of Metamorphic Quartz Sandstone

Abstract： To study rock mechanical characteristics at different unloading velocities, taking the metamorphic quartz sandstone from Dabenliugou quarry special high slope in Jinping Hydropower Station as an example, unloading tests at different unloading velocities and confining pressures were conducted. Based on the tests, relationship curves between stress and strain were obtained, and affection laws of unloading velocity on stress and strain relationship, failure properties, failure stress difference, strength parameters were mainly studied. The results show that the brittle feature of unloading effect on rock failure is more obvious. The specimens under conventional loading test are compression shear failure, while the unloading specimens are tension shear failure. Elastic modulus is decreased with confining. As Vu becomes faster, the nonlinearity become more obvious, while the Poisson ratio is increased slowly. The rock cohesion is reduced but the inner friction angle is increased under unloading condition.