灰土的浸水强度及残余强度的试验研究

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1、第31卷第9期岩土力学Vol.31No.92010年9月RockandSoilMechanicsSep.2010文章编号：1000－7598(2010)09－2781－05灰土的浸水强度及残余强度的试验研究11,211米海珍，王昊，高春，朱浩稳（1.兰州理工大学土木工程学院，兰州730050；2.长江大学工程技术学院湖北荆州434020）摘要：灰土的浸水强度和残余强度在续建工程、改建工程及工程事故分析中经常遇到，故对其进行研究有着重要的工程应用价值。笔者对40余件2：8灰土（兰州黄土与石灰配制）试样进行静三轴试验，探讨其残余强度和浸水条件下强度的变化

2、规律。试验结果发现，灰土的残余强度σR与其围压σ3呈线性关系：σR=Aσ3+B。其规律类似于岩石，原因是由于残余强度阶段灰土碎裂成块，破裂面上的摩擦作用类似于岩石碎裂时的作用；灰土首次浸水后强度有所下降，但随着浸水次数的增加其强度有所回升，最后稳定于一个不高于其原始强度的值；另外还观察到，灰土不可简单地判断为一种脆断性的材料，其脆断性受围压和含水率等因素的制约，围压越大，脆性越不明显，当含水率降低到某一值时灰土表现为脆断性。关键词：灰土；静三轴试验；干湿循环；残余强度；黄土；应力-应变曲线中图分类号：TU443文献标识码：AStudyofimmers

3、ionstrengthandresidualstrengthoflime-loess11,211MIHai-zhen，WANGHao，GAOChun，ZHUHao-wen（1.SchoolofCivilEngineering,LanzhouUniversityofTechnology,Lanzhou730050,China;2.YangtzeUniversityCollegeofTechnology&Engineering,Jingzhou,Hubei434020,China）Abstract:Theimmersionstrengthandresid

4、ualstrengthoflime-loessisanoperationfrequentlyencounteredinsubsequentprojects,reconstructionprojectsandanalyzingtheengineeringaccident.Sotherewillbeanimportantengineeringsignificanceifweworkforit.Theconventionaltriaxialtestwasconductedwithfortysamplesofloess-limeofLanzhouinChin

5、a,theimmersionstrengthandresidualstrengthoflime-loesswerediscussedspecially.FromthesetestsresultsitwasfoundthattheresidualstrengthσRwiththeconfiningpressureσ3appearsalinearrelationship.Thislawissimilartorock,becausethelime-loesswasbrokenintomassesintheperiodoftheresidualstrengt

6、h,andthefrictioneffectonthecrackfacewassosimilartotherock.;thestrengthwilldecreaseafterthelime-loesswasimmersed;butthestrengthwillappearupafterafewtimesimmersion;andthestrengthwillremainonaconstantvolumewhichisnotmorethanitsoriginalstrength.Inaddition,wecan'tdefineitbrittlemate

7、rialssimply.Itisfoundthatthelime'-loessfragilityisdependedonconfiningpressureandwatercontent;theloess-lime'fragilitywillbemoreevidentwhentheconfiningpressurebecomemorehigh.Itwillbefragilitywhenthewatercontentdecreasetoacertainvalue.Keywords:lime-loess;statictriaxialtest;wet-dry

8、cyclingtest;residualstrength;loess;stress-straincurve[