冻融荷载耦合作用下节理岩体损伤本构模型

发布时间：2018-01-17 23:14

本文关键词：冻融荷载耦合作用下节理岩体损伤本构模型　出处：《岩石力学与工程学报》2015年08期 　论文类型：期刊论文

【摘要】：针对寒区节理岩体,提出冻融细观损伤,受荷细观损伤与节理宏观损伤的概念。基于Lemaitre应变等效假设,推导冻融受荷条件下考虑节理岩体宏细观缺陷耦合的复合损伤变量。以完整岩石的初始损伤状态作为基准损伤状态,建立节理岩体冻融受荷损伤本构模型,引用试验资料对模型的合理性进行验证。研究结果表明:(1)岩石在冻融循环过程中引起的细观损伤是一个周期性疲劳破坏的过程,冻融细观损伤随冻融次数近似线性增加,单次冻融循环对岩石造成的损伤较小,为局部损伤;岩石在受荷过程中引起的细观损伤随应变的演化率呈不均匀分布,峰值应变处受荷损伤演化率最大。(2)预制节理对岩石造成的宏观损伤具有明显各向异性,随冻融循环次数的增加,节理岩样的宏观各向异性有所弱化,弱化程度同节理性质和冻融循环次数有关。(3)寒区受荷节理岩体的力学性能由冻融细观损伤,受荷细观损伤与节理宏观损伤及其耦合效应所决定,节理岩体冻融受荷复合损伤变量可以较好地反映节理岩体的抗冻性能。
[Abstract]:For jointed rock mass in cold region, the concepts of frozen and thawed meso damage, loaded meso damage and joint macro damage are put forward, based on the Lemaitre strain equivalence hypothesis. The composite damage variable considering the coupling of macro and meso-defects of jointed rock mass under freeze-thaw loading condition is deduced. The damage constitutive model of jointed rock mass under freeze-thaw loading is established by taking the initial damage state of intact rock as the reference damage state. The rationality of the model is verified by the experimental data. The results show that the meso-damage caused by the rock during freeze-thaw cycle is a periodic fatigue failure process. With the increase of freezing and thawing times, the damage caused by single freeze-thaw cycle is relatively small, which is local damage. In the process of rock loading, the evolution rate of meso-damage caused by the strain is uneven, and the maximum evolution rate of damage caused by loading at the peak strain is the largest. The prefabricated joints have obvious anisotropy to the macroscopic damage caused by the rock. With the increase of freeze-thaw cycles, the macroscopic anisotropy of jointed rock samples is weakened, and the degree of weakening is related to the properties of joints and the number of freeze-thaw cycles. The composite damage variables of frozen and thawed jointed rock mass can well reflect the frost resistance of jointed rock mass.
【作者单位】：中国地质大学工程技术学院;西藏大学工学院;
【基金】：国家自然科学基金资助项目(41002113,41162009) 中央高校基本科研业务专项资金项目(2 9 2014 019)
【分类号】：TU45
【正文快照】： 1引言随着寒区基础设施建设的跟进,实际工程中的岩石往往受到冻融循环、荷载等因素的共同作用,研究冻融循环条件下受荷岩石的损伤力学特性具有重大意义[1]。目前许多学者对此进行了专门研究,如:杨更社等[2-3]利用CT扫描设备对岩石材料在冻融循环条件下的冻融细观损伤扩展特性

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