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针对非贯通裂隙岩体工程结构中的受荷岩体,提出受荷细观损伤与裂隙宏观损伤的概念。以完整岩石的初始损伤状态作为基准损伤状态,综合考虑裂隙宏观缺陷的存在、微裂纹细观缺陷在受荷下的损伤扩展以及宏细观缺陷在受荷过程中的耦合,基于Lemaitre应变等效假设,推导了考虑宏细观缺陷耦合的复合损伤变量,并给出同时考虑试件尺寸、裂隙几何与力学特性的宏观损伤变量的计算公式,从而建立了基于宏细观缺陷耦合的非贯通裂隙岩体在荷载作用下的损伤本构模型。用宏细观损伤耦合的本构模型来描述非贯通裂隙岩体在受荷过程中的细观损伤演化与宏观损伤行为,与非贯通裂隙岩体实际受荷情况符合较好。研究结果表明:(1)完整岩样和裂隙岩样的应力-应变行为在峰值强度之前差异较大,峰值强度以后差异逐渐减小,最后趋于一致,二者具有相近的残余强度;(2)裂隙岩体强度随裂隙贯通率的增加而增大,随裂隙倾角的变化具有明显的各向异性,同时还与裂隙面的内摩擦角有关;(3)裂隙倾角为90°时,裂隙岩样的峰值强度最高;张开型裂隙岩样的裂隙倾角为45°时,峰值强度最低;(4)非贯通裂隙岩体工程结构中的受荷岩体,其力学性能由受荷细观损伤与裂隙宏观损伤及其耦合效应所决定,基于宏细观损伤耦合的复合损伤变量可以较好地反映非贯通裂隙岩样的力学特性。
Aiming at the rock masses under load in the non-through crack rock mass engineering structure, the concept of meso-damage and macro-damage of the rock mass is proposed. Taking the initial damage state of intact rock as the baseline damage state, considering the existence of macroscopic flaw in fracture, the damage propagation of microcrack mesoscopic defect under load and the coupling of macro-scale defect in the process of loading, based on the equivalent of Lemaitre strain It is hypothesized that the composite damage variables considering the coupling of macro and micro defects are derived and the formulas for calculating the macro damage variables considering both the geometry and the mechanical properties of the specimens are given. Damage Constitutive Model of Rock Mass under Load. The meso-damage evolution and macroscopic damage behavior of non-through crack rock mass under loading are described by using the constitutive model coupled with macro and micro damage, which is in good agreement with the actual loading of the non-through rock mass. The results show that: (1) The stress-strain behavior of intact rock samples and fractured rock samples is quite different before the peak intensity, and the difference gradually decreases after the peak intensity finally converges with the similar residual strength; (2) ) The strength of fractured rock mass increases with the increase of fracture penetration rate, and has obvious anisotropy with the change of fracture inclination angle, and also with the internal friction angle of fracture surface. (3) When the fracture inclination is 90 °, the fracture rock The peak intensity is the highest; when the crack angle of the open fractured rock sample is 45 °, the peak intensity is the lowest; (4) The mechanical properties of the rock mass under the non-through fracture rock mass engineering structure are affected by the meso- Compared with the macroscopic damage and its coupling effect, the composite damage variables based on the coupling of macro and micro damage can well reflect the mechanical properties of non-through fractured rock samples.