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1、第30卷增刊2岩土力学Vol.30Supp.22009年12月RockandSoilMechanicsDec.2009文章编号：1000－7598(2009)增刊2－0163－06循环荷载下石灰改良膨胀土临界动应力的探讨1,211周葆春，白颢，孔令伟(1.中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室，武汉430071；2.信阳师范学院土木工程学院，信阳464000)摘要：为探讨各影响因素对石灰改良膨胀土临界动应力的影响规律与程度，进行了振动三轴试验，获得了不同含水率与振动频率下石灰改良膨胀土的临界动应力。基于本文的试验结果
2、，通过石灰改良膨胀土脆性破坏机理分析和临界动应力的影响因素探讨表明，由于石灰的改性作用，导致改良后膨胀土的塑性降低，表现出脆性性质；质量控制指标（掺灰比和压实系数）是影响石灰改良膨胀土临界动应力的决定性因素；由于改性后动力水稳定性较好，石灰改良膨胀土临界动应力受含水率变化的影响有限；而外部动静荷载形式与程度(振动频率和围压)的影响程度较弱。即在保证掺灰比和压实系数的前提下，石灰改良膨胀土的临界动应力能够维持在一个比较稳定的范围内。关键词：高速铁路；路基；膨胀土；石灰改性；临界动应力；动三轴试验；循环荷载；脆性破坏中图分类号：TU443
3、文献标识码：ADiscussiononcriticaldynamicstressoflime-treatedexpansivesoilundercyclicloading1,211ZHOUBao-chun,BAIHao,KONGLing-wei(1.StateKeyLaboratoryofGeomechanicsandGeotechnicalEngineering,InstituteofRockandSoilMechanics,ChineseAcademyofSciences,Wuhan430071,China;2.Collegeof
4、CivilEngineering,XinyangNormalUniversity,Xinyang464000,China)Abstract:Inordertostudythecriticaldynamicstressoflime-treatedexpansivesoilundercyclicloading,thedynamictriaxialtestsunderdifferentwatercontentsanddifferentvibrationfrequenciesarecarriedout.Basedonthetestresult
5、s,theanalysisofbrittlefailuremechanismoflime-treatedexpansivesoilundercyclicloadingandthediscussionontheaffectingfactorsofthecriticaldynamicstressarecarriedout;itisshownthattheplasticityofexpansivesoildecreasesafterlimetreatment,anditsbrittlepropertyappears;thequalityco
6、ntrolindex(dosageoflimeandcompactness)isthedecisivefactorforthecriticaldynamicstress.Andtheinfluenceofwatercontentoncriticaldynamicstressoflime-treatedexpansivesoilappearslimitedbecauseofitspreferabledynamicwaterstability.However,theinfluenceofthetypeandtheextentofexter
7、naldynamicandstaticloads(vibrationfrequencyandconfiningpressure)issolittle.Namely,onconditionofstabledosageoflimeandcompactness,thecriticaldynamicstressoflime-treatedexpansivesoilisusuallystableoverasmallrange.Keywords:high-speedrailways;subgrade;expansivesoil;limetreat
8、ment;criticaldynamicstress;dynamictriaxialtest;cyclicloading;brittlefailure土路基常在水和列车荷载的共同作用下发生下沉外1引言挤、翻浆冒泥等病害，
