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利用自行设计的热–水–力(THM)耦合断裂试验和扫描电镜试验,研究脆性岩石THM耦合断裂的宏微观特征;通过有限元法和新型应力强度因子比断裂准则,判断THM耦合断裂模式,揭示出THM耦合断裂机制。结果表明:红砂岩试件具有3种THM耦合宏观断裂轨迹和对应的3种THM耦合微观断裂特征,即低温、低水压、高围压条件下的断裂轨迹为横向断裂,微观上表现为穿晶的剪切断裂;高温、高水压、低围压条件下的断裂轨迹为纵向断裂,微观上表现为沿晶的拉伸断裂;中等温度、中等水压、中等围压条件的断裂轨迹为双向断裂,微观上表现为含沿晶和穿晶的拉剪复合型断裂。基于有限元法和新型最大应力强度因子比断裂准则判断出的红砂岩试件THM耦合断裂模式与基于宏微观断口分析得到的THM耦合断裂机制完全一致。
The THM coupled fracture and the SEM were used to study the macro and micro characteristics of the THM coupling fracture of brittle rock. The THM coupled fracture mode was judged by the finite element method and the new fracture toughness criterion, Reveal the THM coupling fracture mechanism. The results show that the red sandstone samples have three kinds of THM coupling macroscopic ruptures and three kinds of THM coupling microscopical ruptures, that is, the fractures locates in the horizontal direction under the conditions of low temperature, low water pressure and high confining pressure, The shear fracture under high temperature, high hydraulic pressure and low confining pressure is longitudinal fracture, and microscopic fracture and fracture along the crystal are observed. The fracture trajectory of medium temperature, medium pressure and medium confining pressure is Two-way fracture, microscopic on the performance of the intergranular and transcrystalline tensile shear composite fracture. The THM coupling fracture mode of the red sandstone specimen based on the finite element method and the new maximum stress intensity factor than the fracture criterion is completely consistent with the THM coupling fracture mechanism based on the macro-micro fracture analysis.