双轴循环荷载条件下含预制裂纹类玄武岩岩桥贯通模式  

ROCK BRIDGE COALESCENCE MODE OF BASALT-LIKE MATERIALS WITH TWO PRE-EXISTING FLAWS UNDER BIAXIAL CYCLIC COMPRESSION

作　　者：韩刚[1] 杨帆[2] 刘宇[3] 王延宁 赵幸 赵其华[1] 

机构地区：[1]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),成都610059 [2]四川省地质工程勘察院,成都610072 [3]西华大学应用技术学院,成都611930 [4]山东省第三地质矿产勘查院,烟台264004 [5]重庆地质矿产研究院,重庆400042

出　　处：《工程地质学报》2016年第2期235-245,共11页Journal of Engineering Geology

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

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。The initiation,propagation and coalescence mode of flaws in basalt-like materials with two pro-existingnbsp;flaws are tested under biaxial cyclic compression.The basalt-like materials contain two pre-existing flaws of 30°dip, 20mm length,and 0.3mm thickness,varied rock bridge lengths and dip angles.They are molded using similar materials.The results show that：（1 ）Under biaxial cyclic compression,the failure progress can be divided into wing crack initiation,wing crack propagation and secondary crack initiation,as well as rock bridge coalescence.（2）The coalescence types include shear coalescence,tensile coalescence and shear-tensile compound coalescence.Nine and eight modes can be distinguished particularly using the two experimental methods.（3）In this paper,shear coalescence under biaxial cyclic compression is more possible than that under biaxial compression.Particularly,the crush and uplift phenomenon in rock bridge only exists in biaxial cyclic compression test.（4）Rock bridge coalescence mode is prominently influenced by rock bridge length and dip.With increasing rock bridge dip,the shear coalescence mode and shear-tensile compound coalescence are more undemanding.Under biaxial compression,the shear coalescence mode is predominant accompanied with increasing rock bridge length.However, this pattern is reversed in biaxial cyclic compression test.

关 键 词：玄武岩 相似材料 裂纹扩展 岩桥贯通模式 双轴循环加卸载试验 

分 类 号：P642.3[天文地球—工程地质学]