综合考虑宏细观缺陷的岩体损伤本构模型及破坏机理研究

发布时间：2018-03-21 06:07

本文选题：节理岩体　切入点：宏细观缺陷　出处：《长安大学》2014年博士论文　论文类型：学位论文

【摘要】：岩体是一种既不但含有节理、裂隙等宏观缺陷而且同时又含有微裂纹、微孔洞等细观缺陷的天然损伤地质材料，针对目前岩体损伤本构模型研究中大都仅考虑其中一类缺陷的不足，提出了在岩体力学特性分析中应同时综合考虑宏细观缺陷及其影响效应的观点，并在试验研究与理论分析的基础上建立了相应的岩体损伤本构模型。为此，论文主要进行了以下几方面的研究工作：（1）通过MTS（material teting system）单轴压缩试验及SHPB（split HopkinsonPressure Bar）试验对岩体进行了静、动态压缩试验，分别研究了宏观缺陷（节理）和细观缺陷（微裂纹）对岩体力学特性及破坏模式的影响规律，结果表明两类缺陷对岩体力学特性均有显著影响，不容忽视。（2）基于损伤力学观点，把微裂纹对岩体的损伤作为标量来考虑，采用基于weibull分布的细观统计损伤模型作为不含宏观节理的岩石损伤本构模型，而后在此基础上通过引入二阶损伤张量来描述节理对岩体的宏观损伤，由此建立了相应的岩体损伤本构模型，该模型很好地考虑了宏细观两类缺陷的共同影响。最后利用该模型对节理岩体的力学特性进行了计算，初步验证了该模型的合理性。（3）基于岩体结构力学观点，建立了基于变形元件的岩体损伤本构模型，把岩块视为服从weibull分布的损伤统计本构模型的弹性元件，而把节理面作为闭合变形元件，并考虑试件沿节理滑移对强度和变形影响。算例表明该模型能较好地反映试件强度随节理倾角及节理条数的变化规律，初步说明了该模型的合理性。（4）利用所建立的损伤本构模型对直立层状及顺倾层状岩质边坡的失稳破坏与单节理岩体的强度问题进行了计算分析，认为当考虑了岩体内部同时存在的宏、细观缺陷后，，所得出的结果也将更符合工程实际。
[Abstract]:Rock mass is a kind of natural damaged geological material which not only contains macroscopic defects such as joints and fissures, but also contains microcracks, microvoids and other meso-defects at the same time. In view of the deficiency that only one kind of defects is considered in the present study of damage constitutive model of rock mass, the viewpoint that macro and mesoscopic defects and their influence effects should be considered in the analysis of rock mass mechanical properties is put forward. Based on the experimental study and theoretical analysis, the corresponding damage constitutive model of rock mass is established. 1) static and dynamic compression tests of rock mass were carried out by MTS(material teting system uniaxial compression test and SHPB(split HopkinsonPressure Bar-test. The effects of macroscopic defects (joints) and meso-defects (micro-cracks) on the mechanical properties and failure modes of rock mass were studied respectively. The results show that the two kinds of defects have significant influence on the mechanical properties of rock mass and can not be ignored. (2) based on the viewpoint of damage mechanics, the damage of rock mass caused by microcracks is considered as a scalar, and the meso-statistical damage model based on weibull distribution is used as the constitutive model of rock damage without macroscopic joints. Then, by introducing second-order damage Zhang Liang to describe the macroscopic damage to rock mass, the corresponding damage constitutive model of rock mass is established. The model takes into account the mutual influence of macro and meso defects. Finally, the model is used to calculate the mechanical properties of jointed rock mass, and the rationality of the model is preliminarily verified. Based on the viewpoint of structural mechanics of rock mass, the damage constitutive model of rock mass based on deformation element is established. The rock block is regarded as the elastic element of the statistical constitutive model of damage from weibull distribution, and the joint surface is regarded as the closed deformation element. The effect of slip along joints on strength and deformation is considered. The model can reflect the variation of strength with the joint inclination and the number of joints, and the rationality of the model is preliminarily explained. 4) the damage constitutive model is used to calculate and analyze the instability and strength of vertical and downdip bedded rock slopes. It is considered that the macro- and meso-defects in rock mass are taken into account when the failure of vertical bedded rock slopes and the strength of single-joint rock masses are taken into account. The results will also be more in line with the actual engineering.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU45

【参考文献】