双轴循环荷载条件下含预制裂纹类玄武岩岩桥贯通模式

发布时间：2018-12-29 19:06

【摘要】：揭示双轴循环荷载条件下类玄武岩内裂纹起裂、扩展及岩桥贯通模式。配制类玄武岩相似材料,预制裂纹倾角α=30°、裂纹长度2a=20mm、裂纹厚度l=0.3mm的双裂纹,设计不同岩桥长度L、岩桥倾角β试样,采用双轴压缩、双轴循环加卸载方式,研究裂纹扩展及岩桥贯通模式。试验结果表明:(1)双轴循环加卸载条件下,裂纹扩展-岩桥贯通过程可分为翼裂纹起裂、翼裂纹扩展和次生裂纹起裂及扩展、岩桥贯通3个阶段;(2)岩桥贯通类型可分为剪性贯通、张剪复合贯通和张性贯通3类。双轴压缩条件下,岩桥贯通模式可进一步划分为9种模式,双轴循环加卸载条件下,岩桥贯通模式可分为8种模式;(3)双轴循环加卸载试验比双轴压缩试验更易发生剪性贯通,且在部分试样岩桥处出现局部压碎隆起现象;(4)岩桥倾角β和岩桥长度L对岩桥贯通模式影响显著,随着岩桥倾角的增大,岩桥贯通模式逐渐转变为剪性或张剪性贯通。双轴压缩条件下,岩桥长度增加,贯通模式由张剪复合贯通过渡为剪性贯通,而双轴循环加卸载试验则恰恰相反。
[Abstract]:The model of crack initiation, propagation and bridge connection of basaltic rocks under biaxial cyclic loading is revealed. A similar basalt-like material is prepared with prefabricated crack inclination 伪 = 30 掳, crack length 2aer 20mm and double crack with crack thickness l=0.3mm. Different rock bridge lengths L and rock bridge inclination 尾 samples are designed. Biaxial compression and biaxial cyclic loading and unloading methods are adopted. Crack propagation and rock bridge connection model are studied. The experimental results show that: (1) under biaxial cyclic loading and unloading conditions, the crack propagation-rock bridge can be divided into three stages: wing crack initiation, wing crack propagation and secondary crack initiation and propagation, and rock bridge transfixion; (2) the rock bridges can be divided into three types: shear transfixion, tension-shear composite transfixion and tensional transfixion. Under the condition of biaxial compression, rock bridge transfixion mode can be further divided into 9 modes, and under biaxial cyclic loading and unloading condition, rock bridge through-through mode can be divided into 8 modes. (3) the biaxial cyclic loading and unloading test is more prone to shearing through than the biaxial compression test, and the local crushing uplift occurs at the rock bridge of some samples. (4) the rock bridge obliquity 尾 and the rock bridge length L have significant influence on the rock bridge through-through mode. With the increase of the rock bridge inclination angle, the rock bridge penetrating mode gradually changes into shear or tension-shear transfixion. Under the condition of biaxial compression, the length of rock bridge increases, and the transfixion mode changes from tension-shear composite to shear-through, but the biaxial cyclic loading and unloading test is just the opposite.
【作者单位】：地质灾害防治与地质环境保护国家重点实验室(成都理工大学);四川省地质工程勘察院;西华大学应用技术学院;山东省第三地质矿产勘查院;重庆地质矿产研究院;
【基金】：国家自然科学基金项目(41272333) 国家重点基础研究发展计划(973)项目(2011CB013501)资助
【分类号】：TU45

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