(1. State Key Laboratory of Coal Mine Disaster Dynamics and Control，Chongqing University，Chongqing 400030，China；
2. College of Resources and Environmental Sciences，Chongqing University，Chongqing 400030，China)
Abstract：A series of experiments were carried out with the“multi-functional true triaxial experimental system modeling fluid-solid coupling”to investigate the effect of changing stress Lode angle on the deformation characteristics of sandstone under constant spherical stress and deviation stress( ). The results show that the principal，volumetric and deviatoric strains vary as the stress Lode angle changes. When the deviatoric stress is constant and the spherical stress is variable， ， ， ， and tend to decrease with the increasing of the M(q/p). When the spherical stress is kept constant and the deviatoric stress is variable，the principal，volumetric and deviatoric strains tend to decrease firstly and then to increase with the increasing of M，and the failure of sample occurs when the value of M is relatively large. Some failure planes are parallel approximately to and and perpendicular to . The strength value is significantly smaller than the ones under the conventional loading. The deviatoric stress ratio M has a great influence on the deviatoric strain modulus Gs. The spherical stress affects mainly the volume change of rock. The deviatoric stress affects mainly the rock distortion，and plays an important role in rock failure. The plastic deformation of the sandstone is mainly affected by the Lode angle and the flow direction is equal to .
2017, Vol. 36 
