风化花岗岩破损行为的试验及细观解析

发布时间：2018-05-31 00:36

本文选题：风化花岗岩 + 颗粒离散元　；参考：《华南理工大学》2014年硕士论文

【摘要】：花岗岩广泛分布于华南地区，，受亚热带湿热多雨气候影响，岩石本身发生不同程度的风化。本文选取广州从化地区不同风化程度的花岗岩，基于细观力学的研究方法，揭示其变形机制以及破坏机理。论文研究不同风化程度花岗岩材料从细观到宏观层次的力学行为，并以试验与数值仿真相结合，研究其变形、损伤和非线性断裂的宏观规律，建立岩石材料破损行为的细观离散元模型；建立从多相细观到宏观联系的多尺度研究方法，为研究岩石类非均质准脆性材料破裂机制奠定基础。论文主要研究工作和创新成果有：（1）对风化花岗岩的破损行为进行了巴西劈裂及单轴压缩试验研究，研究了不同风化程度花岗岩的强度及变形破坏规律。（2）基于数字图像处理技术，结合电镜扫描试验鉴定矿物成分，建立反映岩石细观真实结构的离散元模型。基于该模型对平台巴西试验中细观结构、平台中心角及端部摩擦的影响进行了仿真分析，初步验证了模型的可靠性。（3）基于花岗岩不同风化程度试件的断面图片，生成细观结构与之对应的数值仿真试件，对风化花岗岩的强度及破损行为进行了数值仿真研究。（4）引入空间相关随机场表征岩石细观结构的非均质性，实现空间相关随机场的数值生成，并将成果导入颗粒离散元程序PFC中生成相应的细观离散元模型。（5）基于空间相关随机场的细观离散元模型，进行了风化花岗岩的巴西劈裂及单轴压缩数值仿真试验，并将仿真结果与物理试验结果进行了对比分析，结果证明该模型是可靠的。
[Abstract]:The granite is widely distributed in South China and weathered in different degrees under the influence of subtropical humid and rainy climate. In this paper, granites with different weathering degrees in Conghua area of Guangzhou are selected to reveal their deformation mechanism and failure mechanism based on the research method of meso-mechanics. In this paper, the mechanical behavior of granite materials with different weathering degrees from meso to macroscopic level is studied, and the macroscopic laws of deformation, damage and nonlinear fracture are studied by combining experiments with numerical simulation. A mesoscale discrete element model for the failure behavior of rock materials and a multi-scale method for studying the relationship between multiphase meso and macroscopical relations were established, which laid a foundation for studying the fracture mechanism of rock heterogeneous quasi brittle materials. The main research work and innovative achievements are as follows: 1) the fracture behavior of weathered granite was studied by Brazilian splitting and uniaxial compression tests, and the strength and deformation failure of granite with different weathering degrees were studied. 2) based on digital image processing technology and SEM scanning test, a discrete element model is established to reflect the real structure of rock. Based on this model, the effects of the mesoscopic structure, the center angle and the end friction of the platform are simulated and analyzed, and the reliability of the model is preliminarily verified. 3) based on the cross-section pictures of granite samples with different weathering degrees, the corresponding numerical simulation specimens with meso-structures are generated, and the strength and damage behavior of weathered granite are studied numerically. 4) the spatial correlation random field is introduced to characterize the heterogeneity of rock meso-structure, and the numerical generation of spatial correlation random field is realized, and the results are introduced into the particle discrete element program PFC to generate the corresponding meso-discrete element model. 5) based on the mesoscopic discrete element model of spatial correlation random field, the Brazilian splitting and uniaxial compression numerical simulation tests of weathered granite are carried out, and the results of simulation and physical test are compared and analyzed. The results show that the model is reliable.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU45

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