Based on a new elastic clump model, a flexible membrane is proposed for the discrete element numerical simulations of triaxial tests. Conversional triaxial tests of sandstone under the confining pressures of 2 MPa and 8 MPa were carried out, in order to validate the effectiveness of the proposed numerical simulation method. The numerical model is validated by comparing the numerical results with the test results. The deformation and failure process of numerical model is analyzed by stress–strain curves, micro fractures, displacement fields, stress fields and energy fields. The model shows an X-shape shear failure zone, of which the angle is very close to that of the test; the dip angle of most shear fractures is close to the angle of the internal friction; and there is a large amount of slipping frictional heat generated on the failure surface. During the loading process, the stress chain and stress concentration appear in the middle of the model, which lead to displacement zoning in the model. The failure of the model is associated with the growth of the micro tensile- and shear fractures. This study provides an effective tool for the macro–micro investigation of rock failure processes.

基于新的弹性团块模型，提出了一种柔性膜片用于三轴试验的离散元数值模拟。为了验证所提出的数值模拟方法的有效性，在2 MPa和8 MPa的围压下进行了砂岩转换三轴试验。通过将数值结果与测试结果进行比较来验证数值模型。通过应力-应变曲线，微裂纹，位移场，应力场和能量场对数值模型的变形和破坏过程进行了分析。该模型显示了一个X形剪切破坏区域，该区域的角度与测试角度非常接近。大多数剪切裂缝的倾角接近于内摩擦角。破坏面上会产生大量的滑动摩擦热。在加载过程中，应力链和应力集中出现在模型的中间，这导致模型中的位移分区。模型的失败与微拉伸断裂和剪切断裂的增长有关。这项研究为岩石破坏过程的宏观-微观研究提供了有效的工具。