贯通型锯齿状岩体结构面剪切变形及强度特征  

Shear deformation and strength of through-going saw-tooth rock discontinuity

作　　者：黄达[1,2,3] 黄润秋[3] 雷鹏[1] 

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆大学教育部山地城市建设与新技术重点实验室,重庆400045 [3]成都理工大学环境与土木工程学院,四川成都610059

出　　处：《煤炭学报》2014年第7期1229-1237,共9页Journal of China Coal Society

基　　金：国家自然科学基金面上资助项目(41172243);国家自然科学基金重点资助项目(41130745);地质灾害防治与地质环境保护国家重点实验室开放基金资助项目(SKLGP2011K003)

摘　　要：利用二维颗粒流(PFC2D)程序,模拟研究了起伏角及法向应力对贯通型锯齿状岩体结构面的剪切变形及强度影响规律。剪切变形模式可分为爬坡、爬坡啃断和啃断3种基本类型,随着锯齿起伏角和法向应力的增大,逐渐由爬坡、爬坡啃断向啃断模式演变,且这种递变随起伏角和法向应力具有近对称矩阵分布特征。爬坡变形时,结构面两侧存在少量的擦痕及伴生的羽状微裂纹,但锯齿整体损伤破裂轻微,剪应力-剪切位移曲线峰后呈现波动型塑性流动。爬坡啃断变形时,锯齿中上部被剪断,同时结构面两侧也伴生着少量的爬坡摩擦产生的羽状裂纹,剪应力-剪切位移曲线呈现较明显的非线性和波动特征。啃断变形时,锯齿基本沿其根部整体被剪断,结构面两侧间的摩擦滑动损伤不明显,剪应力峰后脆性跃落。随着起伏角及法向应力的增大,剪切破坏时所产生微裂纹、吸收及耗散能量逐渐增多。锯齿状岩体结构面的剪切强度随法向应力及起伏角的增大均近线性增加。建立了一个同时考虑锯齿状结构面爬坡和啃断效应的剪切强度经验公式,并通过边坡稳定性算例得以验证。The influence of inclination angle of saw-tooth and normal stress on shear deformation and strength for through-going discontinuity was investigated using 2D particle flow code （PFC2D）simulation. The shear deformation modes include three basic types climbing along saw-tooth, climbing-gnawing and shearing-gnawing. The modes gradual- ly evolve from climbing and climbing-gnawing to shearing-gnawing with the inclination angle and normal stress increas- ing, and the conversion of these modes approximately presents symmetric matrix distribution with their increase. For the climbing deformation mode, two surface walls of discontinuity have some scrape marks accompanied with pinnate mi- cro-cracks, but saw-tooth overall slightly damage, and the curves of shear stress-displacement present wave-type plastic flow after peak shear stress. For the climbing-gnawing deformation mode, the middle-upper part of saw-tooth was sheared off and accompanied with a small amount of pinnate micro-cracks on the two surface walls, and the curves ofshear stress-displacement present more obviously nonlinear and fluctuating. For shearing-gnawing deformation mode, the saw-tooth is almost entirely cut off along its root and about non-friction damage on the two surface walls, therefore the shear stress obviously present brittle drop-down after peak strength. At the shear failure moment, the micro-cracks, absorption and dissipation of energy gradually increase with inclination angle of saw-tooth and normal stress increas- ing. The shear strength almost linearly increases with inclination angle and normal stress. Taking climbing and gnawing effects into account at the same time,an empirical equation for shear strength of saw-tooth rock discontinuity was established and verified by an instance of slope stability calculation.

关 键 词：岩体力学 结构面 剪切变形 剪切强度 锯齿起伏 

分 类 号：TD313[矿业工程—矿井建设]