基于HCA的细尾矿砂破坏准则试验研究

为研究细尾矿砂破坏准则的具体形式,通过对空心圆柱扭剪仪基本公式推导的方法得出了试验应力路径所需的计算公式;在自行研发的辅助仪器配合下,利用空心圆柱扭剪仪试验的方法测试了细尾矿砂子午平面、π平面上的破坏曲线和不同静水压力下中主应力对各个主应变的影响。结果表明:在子午平面内随着静水压力的增加,破坏点广义剪应力增加;静水压力较小状态π平面内破坏曲线表现为Mohr-Coulomb准则,较大状态表现为Drucker-Prager准则,两种状态静水压力分界点应位于200～300kPa内,破坏准则是否与中主应力有关取决于中主应力对整体应变的影响水平。细尾矿砂的破坏准则应为Mohr-Coulomb与Drucker-Prager准则的组合。

Failure criterion experimental study of fine tailings sand based on HCA

In order to study the failure criterion concrete form of fine tailings sand, the calculation formula of experimental stress path is acquired by deducing the basic formula of hollow cylindrical torsional shear apparatus. With the aid of the self-developed auxiliary instrument, the effect of principal stress on the principal strain of fine tailings in Meridian plane,π plane and principal stress under different hydrostatic pressure was tested respectively, by means of hollow cylindrical torsional shear apparatus. Results show that the characteristic of failure curve in meridian plane is that the generalized shear stress increases monotonously with hydrostatic pressure. The π plane failure curve is consistent with Mohr-coulomb criterion under lower hydrostatic pressure state and consistent with Drucker-prager criterion under larger pressure state.The cut-off point of hydrostatic pressure in two states should be located within 200 and 300kPa.Whether the failure criterion is related to intermediate principal stress depends on influence level of intermediate principal stress on the overall strain. The failure criterion of fine tailings sand should be the combination of Mohr-Coulomb and Drucker-Prager criterion.