综合考虑宏、细观缺陷耦合的节理岩体动态损伤本构模型研究

发布时间：2018-02-20 16:39

本文关键词： 宏细观缺陷破坏模式破坏机理损伤变量动态损伤本构模型　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：在实际工程中,岩体存在着节理、层理、微裂纹和微孔洞等缺陷,按照几何尺寸,可被划分为宏观和细观缺陷。但目前对岩体动态力学特性的研究却忽视了这一特性,由此,提出应建立综合考虑宏、细观缺陷的岩体动态损伤本构模型。本文主要研究内容如下:(1)利用SHPB装置进行了岩体动态压缩试验,对岩体的破坏模式和机理进行了研究,并分析了节理倾角、贯通度和试件长径比对岩体动态力学特性的影响,得出了相关的结论。(2)从宏观和细观两个角度分别对岩体的破坏模式进行了研究分析,主要对裂纹的产生、扩展和贯通过程进行了规律总结。在此认识基础上,利用断裂力学理论对岩体的破坏机理进行了力学分析,提出了裂纹扩展的起裂准则,并计算分析了翼裂纹扩展时的方向和长度。(3)以经典的岩体动态损伤TCK模型为基础,进一步对岩体力学机理进行研究。在考虑岩体力学特性和裂纹尖端应力场作用的基础上,对岩体宏观损伤变量进行定义和计算,并基于Lemaitre应变等效假设对岩体宏观和细观的损伤变量进行耦合计算得到岩体耦合损伤张量,从而建立起本构模型。(4)把岩体看成是由岩体材料和结构元件组合成的等效连续模型,建立起基于变形元件的岩体动态损伤本构模型,进而利用事例对模型进行验证,并探讨分析载荷应变率和节理倾角对岩体动态力学特性的影响规律。最后得出结论。
[Abstract]:In practical engineering, there are defects in rock mass, such as joint, bedding, microcrack and micropore, which can be divided into macroscopic and meso-defects according to geometric size. However, the present study on dynamic mechanical properties of rock mass ignores this characteristic. The dynamic damage constitutive model of rock mass considering macro and meso defects should be established. The main contents of this paper are as follows: 1) the dynamic compression test of rock mass is carried out by using SHPB device, and the failure mode and mechanism of rock mass are studied. The influence of joint inclination angle, penetration degree and the ratio of specimen length to diameter on the dynamic mechanical properties of rock mass is analyzed, and the relevant conclusion is drawn. The failure modes of rock mass are studied and analyzed from macroscopic and meso perspectives respectively, mainly on the generation of cracks. On the basis of this understanding, the failure mechanism of rock mass is analyzed by using the theory of fracture mechanics, and the crack initiation criterion is put forward. The direction and length of wing crack propagation are calculated and analyzed. Based on the classical TCK model of dynamic damage of rock mass, the mechanics mechanism of rock mass is further studied. The mechanical properties of rock mass and the effect of stress field at crack tip are considered. The macroscopic damage variables of rock mass are defined and calculated. Based on the Lemaitre strain equivalent hypothesis, the coupling calculation of the macroscopic and mesoscopic damage variables of rock mass is carried out to obtain the coupled damage Zhang Liang. Thus, the constitutive model of rock mass is established. (4) the rock mass is regarded as an equivalent continuous model composed of rock mass materials and structural elements, and the constitutive model of dynamic damage of rock mass based on deformable elements is established, and the model is verified by examples. The influence of load strain rate and joint dip angle on dynamic mechanical properties of rock mass is discussed.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

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