开挖应力状态下隧道围岩损伤演化及渐进破坏规律研究

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1、重庆交通大学硕士学位论文开挖应力状态下隧道围岩损伤演化及渐进破坏规律研究姓名：徐筠申请学位级别：硕士专业：港口、海岸及近海工程指导教师：赵明阶20080501ABSTRACTCurrently,thetheoryconcernedwiththetunnelsurroundingrockmassdoesnotcatchupwiththedemandoftunnelconstructioninChina．Inthegeotechnicalengineeringworld，increasinglyextensiveattentionshavebeenpaidtotheissue—howtocor

2、rectlyunderstandthefailuremechanismofsurroundingrockmassforsafeexcavationandsupportoptimization．Undertheexternalloadingcondition，cracksgraduallyexpandandtransfix，finallyleadtofailurebecausetherearemanymicroscopicandmacroscopicdeficiencies(damages)includedinthesurroudingrockmass．Intheory,therockmas

3、sstabilityduringexcavationandthesupportsystemdesignmustbaseontheresearchondamageevolvementandfailureruleforthetunnelsurroundingrockmass．Withthisissue，themainjobsofthispaperarebrieflysummarizedasfollows：1．Basedoncontinuousdamagemechanics(CDM)，usingelasticwavevelocitytocharacterizecrackexpanding，the

4、authorestablishedtherelationshipformulasbetweenthequalityindexQ、RMR、BQandtheinitialdamageofsurroudingrockmass．Andtherangeofinitialdamageforeverylevelwasalsocalculated．2．Basedontheprogressivefailurepropertyofrockmass，accordingtoHock’Sphysicalexperimentandamassofstudiesontunnelstability,thefailurepr

5、ocesswhichusuallyelvovesthroughfoursituations，aswellasthetunneldestructionpatternswereconcluded．Undertheunloadingcondition，thefailureofthesurroundingrockmassistheaccumulationofthedamageMongwiththetime．3．Withthedamageparameterdefinedbyelasticwavevelocity,thedamageconstitutiverelationforbrittlerockm

6、assWasestablished．Takingthestressvariationinaccount，thedamageevolvementequationsundertensileandpress‘shearsituation，wererespectivelylisted．4．TakingLonggangtunnelunderconstructioninJilinprovinceasanexample，thispaperdescribedthedamageevolvementofthesurroudingrockmassofdifferentexcavationmethods，thro

7、ughtheanalysisonultrasonicwavetestdata．5．Consideringtheoperatingmodeoffullexcavmionwithoutanysupport，theauthorselectedthetypicalsurroundingrockmassII、III、1VandthedifferentrockmassABSTRACTsituationswithdifferentin