Influence of degree of interlock on confined strength of jointed hard rock masses  

作　　者：Navid Bahrani Peter K.Kaiser 

机构地区：[1]a Department of Civil and Resource Engineering,Dalhousie University,Halifax,Nova Scotia,Canada [2]b Bharti School of Engineering,Laurentian University,Sudbury,Ontario,Canada

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2020年第6期1152-1170,共19页岩石力学与岩土工程学报（英文版）

基　　金：This research was supported by the Natural Sciences and Engineering Research Council of Canada,MIRARCO Mining Innovation,the Center for Excellence in Mining Innovation(CEMI),and Itasca Consulting Group.The authors wish to thank Dr.Evert Hoek for sharing his notes on the historical development of the HB failure criterion including laboratory test data on Panguna andesite and acknowledge his many constructive comments and suggestions during the conduct of the research reported here.

摘　　要：The strength of jointed rock mass is strongly controlled by the degree of interlock between its constituent rock blocks.The degree of interlock constrains the kinematic freedom of individual rock blocks to rotate and slide along the block forming joints.The HoekeBrown(HB)failure criterion and the geological strength index(GSI)were developed based on experiences from mine slopes and tunneling projects in moderately to poorly interlocked jointed rock masses.It has since then been demonstrated that the approach to estimate the HB strength parameters based on the GSI strength scaling equations(called the‘GSI strength equations’)tends to underestimate the confined peak strength of highly interlocked jointed rock masses(i.e.GSI>65),where the rock mass is often non-persistently jointed,and the intact rock blocks are strong and brittle.The estimation of the confined strength of such rock masses is relevant when designing mine pillars and abutments at great depths,where the confining pressure is high enough to prevent block rotation and free sliding on block boundaries.In this article,a grain-based distinct element modeling approach is used to simulate jointed rock masses of various degrees of interlock and to investigate the influences of block shape,joint persistence and joint surface condition on the confined peak strengths.The focus is on non-persistently jointed and blocky(persistently jointed)rock masses,consisting of hard and homogeneous rock blocks devoid of any strength degrading defects such as veins.The results from this investigation confirm that the GSI strength equations underestimate the confined strength of highly interlocked and non-persistently jointed rock masses.Moreover,the GSI strength equations are found to be valid to estimate the confined strength of persistently jointed rock masses with smooth and non-dilatant joint surfaces.

关 键 词：Rock mass strength Degree of interlock Non-persistently jointed rock mass Blocky rock mass Geological strength index(GSI) GSI strength equations 

分 类 号：TU45[建筑科学—岩土工程]