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采用双线性应变软化本构模型结合能量耗散原理建立了损伤本构方程,并通过应变能密度理论建立了细观单元岩石破坏的能量判别准则。当某一单元所存储的应变能超过某固定值时,单元进入损伤状态,同时单元的损伤程度随着能量耗散的增加而增加,损伤单元的材料属性也随之改变,直到变为具有一定残余强度的单元。随着荷载增加,单元损伤的程度变大,当单元储存的应变能超过所建立的能量判别准则时,定义单元破坏,随着破坏单元的数目不断增多,破坏单元相互连通形成宏观裂纹,实现了利用线性计算完成非线性计算的过程,避免了数值计算在单元断裂时的奇异性,模拟了岩石的峰后破裂行为。对上述算法利用FLAC中的FISH语言开发了岩石破裂化计算程序,并将该程序成功应用于巴西劈裂和中间裂隙拉伸试验的破裂模拟过程中,其模拟结果与相应的理论和试验结果吻合较好,说明该方法对于模拟岩石破裂过程的正确性和可行性。
The damage constitutive equation was established by using the bilinear strain softening constitutive model combined with the energy dissipation principle. The energy criterion of rock failure in mesoscopic units was established by using strain energy density theory. When the strain energy stored in a cell exceeds a certain value, the cell enters the damage state, meanwhile, the damage degree of the cell increases with the increase of energy dissipation, and the material properties of the damage cell change accordingly until it becomes a constant Residual strength of the unit. As the load increases, the extent of cell damage becomes larger. When the stored strain energy of the cell exceeds the established energy criterion, the cell is defined to be destroyed. As the number of destroyed cells increases, the damaged cells are interconnected to form a macro-crack, The linear calculation is used to complete the non-linear calculation, which avoids the singularity of numerical calculation in unit fracture and simulates the post-peak fracture behavior of rock. The above algorithm has been developed using FISH language in FLAC and has been successfully used in the fracture simulation of Brazilian and intermediate fracture tensile tests. The simulation results agree well with the theoretical and experimental results Better, indicating the correctness and feasibility of the method for simulating the rock fracture process.