摘要
雁行分布是岩体中重要的裂纹分布形式之一,且对裂隙岩体力学性质有重要影响。本文通过模拟试验手段,较为系统地研究了含两条雁行典型裂纹岩体试样的预制裂纹倾角、侧压、裂纹面摩擦系数等因素对试样单轴抗压强度、第一主应力、剪切应力以及贯通破坏模式的影响规律;运用应力极值线定义得到了裂纹尖端的拉应力、剪应力极值线,分析了这两类极值线的分布特征,揭示了雁行分布裂纹条件下次生张拉裂纹、次生剪切裂纹的起裂、发展、贯通路径与机理,总结了两条雁行分布裂隙岩体试样贯通模式的演化规律。研究表明:两条雁行裂纹岩体试样,预制裂纹倾角从0°逐步增大到70°,试样峰值强度先减小而后增大,最小值出现在裂纹倾角在40°~45°区间时;侧压会显著削弱裂纹倾角对试样峰值强度的影响;裂纹倾角较小时,裂纹面摩擦系数对试样峰值强度影响显著,反之影响甚微;当裂纹倾角小于30°时,试样裂纹端部先张拉破坏,且易于形成剪切贯通次生裂纹;当裂纹倾角大于50°时,试样先张拉破坏,且易于形成张拉贯通次生裂纹;当裂纹倾角在30°~50°间时,试样易于形成拉剪复合性贯通次生裂纹。
Non-coplane distribution of cracks is an important model in fractured rocks and dominates their failure mode. In this paper,the influences of non-coplane pre-cracks dip to stress field, failure mode and failure mechanism are studied by means of systemic numerical experiments and typical model tests via considering crack dip, confining pressure and friction coefficient of pre-crack. The results show that: for these samples with two non-coplane pre-cracks, with the pre-crack dip increasing from 0° to 70°, the peak strength of rock sample goes down firstly and goes up after the turning point located between pre-crack dip 40° to 45°;confining pressure can reduce dramatically the influence of pre-crack dip on the peak strength of rock sample;when the pre-crack dip is smaller than 45°, the friction coefficient of pre-crack has great influence on the peak strength of rock sample, vice versa;when the pre-crack dip is smaller than 30°, the crack coalesce is trigged by the shear secondary crack in rock bridge;when the pre-crack dip is larger than 50°, the crack coalesce is induced by the tensile secondary crack in rock bridge;between 30° and 50°, the crack coalesce is caused by the compound of shear and tensile secondary crack.
作者
张志强
陈方方
李宁
许强
郝志远
Zhang Zhiqiang;Chen Fangfang;Li Ning;Xu Qiang;Hao Zhiyuan(Institute of geotechnical engineering,Xi’an University of Technology,710048,Xi’an,China;School of Architecture&Civil Engineering,Xi’an University of Science and Technology,710054,Xi’an,China)
出处
《应用力学学报》
CAS
CSCD
北大核心
2020年第5期2280-2287,I0031,共9页
Chinese Journal of Applied Mechanics
基金
国家自然科学基金(11872301)
陕西省教育厅科研计划项目(17JS091)
西安市城建专项资金支持项目(SJW2017-14)。
关键词
裂隙岩体
雁行分布裂纹
破坏模式
应力场
机理分析
fractured rock mass
non-coplane crack
failure model
stress field
mechanism analysis
作者简介
第一作者:张志强,男,1976年生,博士,西安理工大学,副教授,研究方向——裂隙岩体力学。E-mail:zhangzq87@xaut.edu.cn。
