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充分考虑岩石材料缺陷随机性的特点,基于连续损伤力学理论,建立了考虑围压影响的冻融荷载作用损伤模型;根据红砂岩变形破坏曲线的几何条件,采用全微分方法确定了仅含岩石基本特征参量的模型参数表达式;通过红砂岩冻融循环力学特性试验,验证了模型的合理性。研究表明:红砂岩以裂纹为主导的细观力学响应与宏观变形破坏特性相一致;随着冻融循环次数的增加,岩石损伤程度加剧,宏观上表现为材料力学性能的劣化。但在变形中后期,相同损伤程度时岩石应变增加,塑性特性增强;围压可改善岩石受力状态,因而随着围压的增加,岩石损伤程度减小,宏观上表现出材料抵抗破坏能力的增强和塑性变形的增加。
Based on the theory of continuous damage mechanics, the damage and freeze-thaw model considering the effects of confining pressure was established. The geometrical conditions of the deformation and failure curves of red sandstone were determined by using the method of total differential, The parameters of the model parameter expression; through the red sandstone freeze-thaw cycling mechanical properties test, the model is validated. The results show that the crack-dominated red sandstone mesomechanical response is consistent with the macro-deformation failure characteristics. With the increase of the number of freeze-thaw cycles, the damage degree of the rock is aggravated, and the mechanical properties of the material deteriorate macroscopically. However, in the middle and late stages of deformation, the rock strain increases and the plastic properties increase with the same degree of damage. The confining pressure can improve the rock stress state. Therefore, with the increase of confining pressure, the damage degree of the rock is reduced and the material is resistant to the damage Increased and plastic deformation increases.