一类含裂隙岩质边坡滑动弱化逐步破坏机理

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1、第23卷第21期岩石力学与工程学报23(21)：3679～36832004年11月ChineseJournalofRockMechanicsandEngineeringNov.，2004*一类含裂隙岩质边坡的滑动弱化逐步破坏机理张均锋丁桦徐永君孟祥跃(中国科学院力学研究所北京100080)摘要含裂隙的岩土材料在剪切作用下，随着剪应变的增加，裂纹端部一定区域内的强度会表现出滑动弱化的现象。岩土材料这种性质的变化不同于粘性土结构性破坏，也不同于剪胀。在一定的载荷作用下，坡体内裂隙端部的滑动弱化使坡体内的应力重新分配，从而使得应力集中加剧，裂隙尖端进一步扩展，造成岩体结构性的破坏

2、，乃至整个滑面的贯通直至发生滑坡。因此，滑动弱化是一类含裂隙岩质边坡滑坡的机理。关键词岩石力学，岩质边坡，滑动弱化，逐步破坏分类号TU457文献标识码A文章编号1000-6915(2004)21-3679-05MECHANISMOFPROGRESSIVEFAILUREOFAKINDOFFAULTEDROCKSLOPEDUETOSLIP-WEAKENINGZhangJunfeng，DingHua，XuYongjun，MengXiangyue(InstituteofMechanics，TheChineseAcademyofSciences，Beijing100080China)

3、AbstractSlip-weakeningisoneofthecharacteristicsoffaultedrockmaterialunderacertainloadingcondition.Non-uniformrockstructuremayexistinthevicinityoftheslipsurfaceinarockslope.Someportionsoftheslipsurfacemaybemutuallypenetratedbuttheothersmaynot.Forthelattercase，thecracksorthefaultsurfaceswill

4、undergosheardeformationbeforeasuccessivesurfaceformsundercertainloadings.Astheslippedportionadvances，slip-weakeningoccursoveradistancebehindthecracktip.Intheweakeningzone，theshearstrengthwilldecreasefromitspeakvaluetoresidualfrictionlevel.Thestresswillredistributealongthecracksurface.There

5、forethechangedlocalstressconcentrationwillcausethecracktoextendandtheratioofpenetrationoftheslipsurfacewillincrease.Fromthelarge-scaleviewofthewholeslipsurface，theshearstrengthwilldecreaseduetothedamageoftheinteriorrockstructure，andthefaultedrockbehavesasasofteningmaterial.Suchakindofmecha

6、nismhappensinmanypracticallandslidessubjectedtostrongearthquakes.Itshouldbenotedthatthismechanismisdifferentfromthatofthebreakageofstructuralclay，inwhichthegeologicalmaterialisregardedasamediumcontainingstructurallumpsandstructuralbands.Thestrain-softeningpropertyexhibitedinthestructuralcl

7、ayistheresultofstructuredamage(i.e.thedisintegrationofthesoilstructure).Thesofteningbehavioroffaultedrockshouldberegardedasacomprehensiveresultofthewholecomplicatedprocessincludingslip-weakening，stressredistribution，cracktipextensionandthepenetrationofslipsurf