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1、第31卷第12期岩土力学Vol.31No.122010年12月RockandSoilMechanicsDec.2010文章编号:1000-7598(2010)12-3704-06干湿交替对砂岩力学特性影响的试验研究1,22113姚华彦,张振华,朱朝辉,施一春,李元(1.合肥工业大学土木与水利工程学院,合肥230009;2.三峡大学三峡库区地质灾害教育部重点试验室,湖北宜昌443002;3.二滩水电开发有限责任公司,成都610051)摘要:由于地下水位的升降等原因,岩体经常处于干湿交替状态,这对岩体工程的长期稳定性不利。以红砂岩为研究对象,进行了干燥-饱水干湿交替作用后的
2、常规单轴和三轴压缩试验研究,获得了砂岩应力-应变曲线,分析了其变形破坏特征。相对于没有经过干湿交替作用的干燥试件,经过不同次数的干燥-饱水交替作用后,砂岩的弹性模量、单轴和三轴抗压强度、黏聚力、内摩擦角等都有不同程度的降低。各力学指标的总体变化趋势是在第1次饱水之后均有较大幅度的下降,此后,随着干湿交替作用次数增加其降低的幅度逐渐减小,干湿交替作用使岩石的延性增强。在围压作用下,砂岩的峰值强度均随着围压的增大而增大,干燥试件强度的围压效应要比多次干湿交替作用后的试件显著。关键词:岩石力学;试验研究;力学特性;干湿交替;变形;强度中图分类号:TU411文献标识码:AExp
3、erimentalstudyofmechanicalpropertiesofsandstoneundercyclicdryingandwetting1,22113YAOHua-yan,ZHANGZhen-hua,ZHUChao-hui,SHIYi-chun,LIYuan(1.SchoolofCivilandHydraulicEngineering,HefeiUniversityofTechnology,Hefei230009,China;2.KeyLaboratoryofGeologicalHazardsonThreeGorgesReservoirArea,Minist
4、ryofEducation,ChinaThreeGorgesUniversity,Yichang,Hubei443002,China;3.ErtanHydropowerDevelopmentCo.,Ltd.,Chengdu610021,China)Abstract:Cyclicwettinganddryingusuallyoccursinrockmassforsomereasonssuchaswaterlevelvariation,whichisfairlyharmfulforitslongtermsafety.Aseriesofuniaxialandtriaxialc
5、ompressionexperimentaltestsonsandstoneundercyclicdryingandwettinghavebeencarriedout.Thecorrespondingcompletestress-straincurvesareobtained;andcharacteristicsofdeformationandfailureareanalyzed.Comparedwiththedryspecimens,elasticmodulus,cohesion,internalfrictionangle,uniaxialandtriaxialcom
6、pressivestrengthsofthespecimensunder“dry-saturation”cyclingarealldecreasedtosomedegree.Thegeneraltrendisthatallmechanicalindiceshavearelativelysharpdeclineafterthefirsttimesaturatedwithwater;andthereafter,decreasegraduallyfollowedbyanincreaseincyclingtimes.Therocksamplesbecomemoreductile
7、undercyclicdryingandwetting.Sandstonepeakstrengthincreasesalongwiththeincreasingofconfiningpressure.Theeffectofconfiningpressureonpeakstrengthisgreaterfordryspecimensthanfor“dry-saturation”cyclingspecimens.Keywords:rockmechanics;experimentalstudy;mechanicalproperties;cycl