采用平行粘结细观本构模型,在岩石颗粒尺度上研究了压头侵入岩石的破坏过程。分析讨论了岩石材料平行粘结模型细观参数与宏观力学参数之间的映射关系。为了实现表征颗粒连接破坏模式,应用FISH语言编写一个伺服程序,检测每个颗粒连接的受力状态。依据所建立的颗粒连接破坏准则,并对每个颗粒连接进行破断与否的评估,实现描述颗粒连接的破坏功能。研究表明,在压头垂直压力作用下,岩石试件内形成了3条主环向拉力链,它与宏观的小主应力方向一致。环向拉力链最大影响深度随着压头压入深度的增加而增加。与此同时,出现了几条径向压力链,它与宏观的大主应力方向基本一致。岩石试件裂纹是由环向拉应力和剪应力大于颗粒平行连接胶结材料的强度引起的。
The parallel bond model in discrete element method is used to simulate the fracturing process of rock specimen under action of indenter. The nonlinear mapping relations between meso-parameters of constitutive model and macro mechanical parameters of rock specimen are analytically bridged. In order to characterize the fracture mode between the bonds of parcels each other,the serving program is coded with FISH language,and the stress states for every bound is checked. Based on the proposed fracturing criterion for the bonds of parcels,the evaluation for whether exists fracture between the bonds of parcels is performed. The investigation shows that under the action of vertical indenter,the tree tensile force chains are produced in circumferential direction,and their directions are same as the directions of the minor principal stress. The directions of radial compressive force chains are same as the directions of the major principal stress. The cracks in rock specimen are induced by tensile force in circumferential direction and shear force when the tensile stress or shear stress is larger than material strength.