华南风化花岗岩劈拉断裂行为的试验与细观模拟研究

发布时间：2018-01-10 01:23

  本文关键词：华南风化花岗岩劈拉断裂行为的试验与细观模拟研究　出处：《工程力学》2017年06期 　论文类型：期刊论文

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【摘要】：为研究不同风化程度花岗岩在劈拉受载下的破损行为,该文对广东从化地区新鲜、微风化、中风化三种风化程度的花岗岩进行微观特征测量及巴西圆盘试验研究。分别基于考虑空间相关特征的随机模型和数字图像技术两种方法实现对岩样细观结构的表征,结合细观参数反演技术,建立反映岩石细观非均质组构特性的颗粒离散元模型,对花岗岩劈拉试验进行数值仿真试验研究。结果表明,随着风化级别的提高,花岗岩中粘结力较强的长石等矿物向粘土矿物转化,结晶强度降低,微孔隙等软弱结构增多,岩石宏观力学性能不断劣化,劈拉破坏由单一裂纹主导转为多条分叉状裂纹,岩样脆性也逐渐减弱。基于两种方法建立的细观随机力学模型仿真结果均表明岩样的劈拉强度随风化级别的提高逐渐降低,与试验结果变化趋势相符,分析得到不同风化花岗岩的劈拉破裂响应特征与试验结果一致,且从细观层面对花岗岩样受劈拉作用的渐进破裂响应提供了深入认识。
[Abstract]:In order to study the breakage behavior of granite with different weathering degree under splitting load, this paper is fresh and breezy in Conghua area, Guangdong Province. Three kinds of weathered granites with medium weathering degree were measured by microcosmic characteristics and studied by Brazilian disk test. Based on the stochastic model with spatial correlation and digital image technology, the mesoscopic structure of rock samples was realized. Sign. Combined with the technique of mesoscopic parameter inversion, a discrete element model of particles reflecting the characteristics of meso-heterogeneous fabric of rock is established, and the numerical simulation experiment of granite splitting tensile test is carried out. The results show that with the increase of weathering level. The feldspar and other minerals with strong adhesion in granite are transformed into clay minerals, the crystallization strength decreases, the weak structures such as micropores increase, and the macroscopic mechanical properties of the rocks continue to deteriorate. Cleavage failure is changed from single crack to multiple branched crack. The simulation results of mesoscopic stochastic mechanics model based on the two methods show that the splitting tensile strength of rock samples decreases with the increase of weathering level, which is consistent with the change trend of test results. The characteristics of cleavage fracture response of different weathered granites are consistent with the experimental results, and a deep understanding of the progressive fracture response of granitic samples subjected to split tension is provided from the meso level.
【作者单位】： 华南理工大学土木与交通学院;清华大学水利水电工程系;华南理工大学亚热带建筑科学国家重点实验室;
【基金】：国家自然科学基金项目(51109083) 中央高校基本科研业务费项目(2014ZZ0009) 国家自然科学基金委员会-中国铁路总公司高速铁路基础研究联合基金项目(U1434211) 中电建华东勘测设计院有限公司2013年科技项目(SD2013-10)
【分类号】：TU452
【正文快照】： 华南地区花岗岩长时间受外界自然条件影响,尤其是强烈地风化作用,导致其矿物成分、结构状态、物理力学性质等均产生一定改变。特别是广东地区,气候更加温暖湿润,工程地质性质特殊,花岗岩受化学风化作用更强烈,风化程度差异较大,使得该地区环境灾害、工程地质灾害经常发生。作，

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