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1、第31卷第1期岩土力学Vol.31No.12010年1月RockandSoilMechanicsJan.2010文章编号:1000-7598(2010)01-0246-07拉西瓦水电站地下厂房三维高地应力反演分析11,2111姚显春,李宁,曲星,孙宏超,景茂贵(1.西安理工大学岩土工程研究所,西安710048;2.中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,兰州730000)摘要:拉西瓦水电站厂房地处峡谷山高坡陡,河谷狭窄,区域地应力场较高,局部存在构造破碎带,同时开挖尺寸规模巨大,围岩主要为脆硬的花岗岩,对洞室稳定极为不利。为了评判开挖后围岩的稳定及支护设计的长期安全,
2、需要对围岩的岩体力学参数和初始应力场进行反演确定。首先,利用现场初始地应力的实测值反演大范围内的岩体构造地应力场分布,然后,利用洞室分层开挖扰动下,厂房上部关键点实测位移检验并修正反分析地应力结果,得到了较为准确的三维地应力分布,为后续地下厂房开挖围岩的稳定性及支护设计和长期安全的评价与预测,提供了基础数据,有效地指导了厂房开挖施工。厂房开挖完成后的围岩位移的实际监测结果与采用反演地应力场与岩体参数得到的厂房围岩位移值的一致性表明,地应力场反演结果与实际地应力值一致。关键词:地下洞室群;高地应力;反演分析;拉西瓦水电站中图分类号:TU443文献标识码:ABackanalysisofth
3、ree-dimensionalinitialgeostressLaxiwaundergroundpowerhouse11,2111YAOXian-chun,LINing,QUXing,SUNHong-chao,JINGMao-gui(1.InstituteofGeotechnicalEngineering,Xi’anUniversityofTechnology,Xi’an710048,China;2.StateKeyLaboratoryofFrozenSoilEngineering,CAREERI,ChinessAcademyofSciences,Lanzhou730000,China
4、)Abstract:LaxiwaHydropowerstationislocatedinahighmountainvalleyandnarrowvalleys,wheretheregionalgeostressfieldishigher.Besides,localexistenceoftectonicfracturezoneandsizeoflarge-scaleexcavationarecommonphenomenainthisproject.Thesurroundingrockofhydropowerplantismainlygranite,whicharehardandbritt
5、lerock,thiskindofrockisverydetrimentaltothestabilityofthecavern.Inordertojudgethestabilityofsurroundingrockafterexcavationandlong-termsecurityofsupportdesign,itisneedforobtainingmechanicalparametersofsurroundingrockmassandtheinitialstressfield.Basedonthemeasuredvaluesoftheinitialstressin-situ,ro
6、cktectonicstressfielddistributionoflarge-scalerockmassisobtainedthroughbackanalysis;thenusingdisplacementofthekeypoint,measuredatthetopofstratifiedcaveexcavationdisturbance,obtainthemoreaccuratethree-dimensionalstressdistributionresults.Forfollow-upexcavationofundergroundpowerhouse,evaluationand
7、predictionofstabilityofsurroundingrockandlong-termsafetyofsupportdesign,thebasicdataareprovidedforeffectivelyguidingthefollowingexcavationofplant.Displacementsofsurroundingrockafterthecompletionexcavationobtainedbyusingrockm