中文摘要：

以重庆市境内的典型石英砂岩为例，通过室内单轴拉伸和压缩试验，得到了砂岩单轴抗拉强度与抗压强度的比值；划分了单轴拉伸和压缩试验过程的各个阶段及所占的比例。室内三轴压缩试验发现砂岩的极限抗压强度随着围压的升高而升高，在此基础上求出极限抗压强度与围压之间的二次非线性关系式；通过莫尔应力圆的绘制，得到了砂岩的粘结力和内摩擦角，并由3种不同应力状态下的莫尔应力圆，得出砂岩二次抛物线型强度包络线的表达式。

英文摘要：

Based on typical sandstone samples collected in Chongqing City, and by conducting indoor uniaxial tensile and compression tests, the ratio of uniaxial tensile strength to compressive strength is obtained;and several phases in the two tests are divided and their proportion are made clear. The triaxial compression test shows that ultimate compressive strength increases with increment of confining pressure, based on which, the quadratic nonlinear relationship between compressive strength and confining pressure is obtained. Through drawing Mohr stress circles, the cohesion and internal friction angle of sandstone samples are cal-culated, and quadratic parabolic expression of strength envelope is obtained through different Mohr stress circles under three dif-ferent confining pressures.