单轴压缩下层状含水页岩损伤破坏过程及特征

发布时间：2018-03-18 18:30

本文选题：层状页岩　切入点：含水率　出处：《岩土力学》2017年06期 　论文类型：期刊论文

【摘要】：页岩在重庆地区分布较广,在隧址围岩赋存环境中占较大比重,考虑到层理和水对页岩性质影响显著,因此,对页岩在层理和含水率影响下损伤破坏过程和劣化机制进行研究。试验借助于MTS815岩石力学测试系统和PAC声发射仪,进行单轴压缩条件下层状页岩损伤破坏过程的声发射试验研究,并采用大型离散元软件3DEC对页岩破坏模式进行对比分析。研究结果表明:(1)页岩的矿物成分、矿物排列和加载方向决定其损伤破坏过程,原生微裂隙的分布、矿物晶粒大小和加载方向决定了宏观裂隙的分布,宏观裂隙则控制着页岩的破坏模式。(2)页岩内部沿层理方向原生微裂隙群是页岩破坏起裂部位,次生微裂隙常沿矿物边界发展,与加载方向基本一致,最终形成宏观裂隙,起到连通层理破裂面的作用。(3)层状页岩AE事件的生成和分布与试件内部的微裂隙分布关系密切,初始压密阶段积聚于试件中部层理附近,后沿层理法向方向向端部或两侧发展,最终沿宏观裂隙转折及交点处聚结成核。(4)层理和水对页岩的损伤劣化机制不同,层理对页岩的损伤作用本质上是沿层理分布的原生微裂隙群的损伤作用,而水对页岩的损伤作用主要是水的吸附和毛细管压力作用。
[Abstract]:Shale is widely distributed in Chongqing area and occupies a large proportion in the surrounding rock environment of tunnel site. Considering that bedding and water have significant influence on shale properties, therefore, The damage and failure process and degradation mechanism of shale under the influence of bedding and moisture content were studied. The experiment was carried out by means of MTS815 rock mechanics test system and PAC acoustic emission instrument. The damage and failure process of layered shale under uniaxial compression was studied by acoustic emission test, and a large discrete element software 3DEC was used to compare and analyze the failure mode of shale. The distribution of primary microcracks, the size of mineral grains and the direction of loading determine the distribution of macroscopic fractures. The macroscopic fissures control the failure mode of shale. (2) the primary microfracture group along the bedding direction is the initiation site of shale failure, and the secondary microfracture often develops along the mineral boundary, which is basically consistent with the loading direction, and finally forms the macroscopic fracture. The formation and distribution of AE events in layered shale is closely related to the distribution of microfractures in the specimen, and the initial compaction stage accumulates near the middle of the specimen, and then develops to the end or both sides along the normal direction of the layer. The mechanism of damage degradation of shale is different from that of water. The damage effect of bedding on shale is essentially the damage of primary microfracture group distributed along the bedding. The damage of water to shale is mainly caused by water adsorption and capillary pressure.
【作者单位】：重庆大学煤矿灾害动力学与控制国家重点试验室;重庆大学资源及环境科学学院;
【基金】：煤矿灾害动力学与控制国家重点试验室自主课题重点项目(No.2011DA105287-ZD201504)~~
【分类号】：TU452

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