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为了探究含软、硬两种岩性碎块石土石混合体的变形破坏过程与力学性质,发展了一种基于软硬石模板库的土石混合体建模方法。通过在PFC2D中建立符合原位结构特征的软硬石模板库,利用此模板库生成了不同含石量土石混合体颗粒流模型,对土石混合体进行了单轴压缩颗粒流模拟。结果表明:土石混合体破坏始于土-石接触面,土石介质分离大多因剪切破坏导致,加载前期微裂纹迅速增长,中、后期微裂纹增长速率减缓,但宏观变形渐趋显著;随着含石量的增加,土石混合体单轴抗压强度逐渐降低,块石的转动与侧向移动会加剧土石混合体的整体破坏;相同含石量下,随着软石比例的增加,单轴抗压强度呈下降趋势,试验后试样破裂率与单个软石颗粒的破裂程度均保持在较高水平,软石颗粒破裂是引起土石混合体单轴抗压强度降低的重要原因。
In order to explore the deformation and failure process and mechanical properties of the rock-soil mixture containing both soft and hard rock fragments, a soil-rock mixture modeling method based on soft and hard template library was developed. Through the establishment of the soft and hard template library in PFC2D which is in line with the in-situ structural features, the particle flow model of rock-soil mixture with different stone-containing contents was generated and the uniaxial compression particle flow simulation of soil-stone mixture was carried out. The results show that the failure of soil-rock mixture begins at the soil-stone contact surface, and the separation of soil-rock media is mostly caused by shear failure. The pre-loading microcracks increase rapidly and the microcracks grow slowly in the middle and late stages. However, The uniaxial compressive strength of soil-rock mixture gradually decreases with the increase of rock content, and the overall failure of rock-soil mixture will be aggravated by the rotation and lateral movement of rock mass. With the increase of the proportion of soft rock, The compressive strength shows a downward trend. After the test, the rupture rate of the sample and the rupture degree of the single soft rock particles are all kept at a high level. The rupture of the soft rock particles is the important reason that causes the uniaxial compressive strength of the rock-soil mixture to decrease.