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本文通过三种尾矿砂的三轴剪力试验对尾矿砂在高压力下的变形与强度特性进行了研究。试验表明,颗粒破坏的数量随着剪切变形和侧限压力的增大而增多,与试样的初始密度却无直接关系。在高压力下摩尔包线的形状稍弯曲,在本文试验的压力范围内(侧限压力小于70kg/cm~2),内摩擦角比在通常试验的压力下(侧限压力小于10kg/cm~2),可减小达8°～13°,比砂土在同样条件下减小得多一些。因此在进行尾矿坝稳定与变形分析时,都应考虑这种影响,即根据高压力下的试验结果,计算尾矿砂的抗剪强度、切线模量与切线油松比。文中对用低压力下内摩擦角所算得的切线模量、切线泊松比和考虑高压力下强度非线性变化计算的数值进行了比较。试验还表明,高压力下的切线泊松比,用但尼尔建议的方法进行计算与实测资料相符,用轴向应变与侧向应变为双曲线关系的假设进行计算则相差较大。
In this paper, the deformation and strength characteristics of tailings sand under high pressure are studied by the triaxial shear tests of three tailings sands. Tests have shown that the number of particle failures increases with increasing shear deformation and lateral pressure, which is not directly related to the initial density of the sample. Under high pressure, the shape of the mole envelope is slightly curved, within the pressure range tested in this article (side pressure is less than 70kg/cm~2), the internal friction angle ratio is under the pressure of the normal test (side pressure is less than 10kg/cm~ 2) It can be reduced to 8° to 13°, which is much less than sand under the same conditions. Therefore, in the analysis of tailings dam stability and deformation, this effect should be considered, that is, according to the test results under high pressure, calculate the shear strength, tangent modulus and tangential Pinus ratio of tailings sand. In this paper, the tangent modulus, the tangential Poisson ratio calculated with the internal friction angle under low pressure, and the values calculated with the nonlinear variation of the strength under high pressure are compared. The experiment also shows that the tangential Poisson’s ratio under high pressure is consistent with the measured data using the method suggested by Danielle. The calculation using the hypothesis that the axial strain and the lateral strain are hyperbolic is quite different.