饱和黄土液化标准的试验研究
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摘要
根据饱和黄土在动荷载振动作用下的试验结果提出了以黄土的3%应变为主要考虑因素的液化破坏标准。试验表明:在固结不排水的动三轴试验中,黄土结构连接强度随循环次数的增加而逐渐丧失,体积收缩,在不排水条件下转化为孔隙水压力的上升和有效应力的下降,最终可能出现"初始液化"和"循环活动性"现象。3%轴应变一定出现在"初始液化"前;3%轴应变后应变大幅增加,孔压有可能达到初始有效固结围压,也有可能在"初始液化"前破坏。3%轴变形是黄土稳定变形和大幅变形的临界点。
Based on the result of saturated loess in dynamic triaxial test the 3%axial strain is put forward as the key parameter of the liquefaction criterion.The tests show:for the consolidated-undrained tests(CU)of the undisturbed loess, with increasing of the cycles,the structural bonding strength fades away and the volume shrinkage,which transforms into increasing of the pore pressure and decreasing of the effective stress.At last,the"initial liquefaction"and"cyclic activity" phenomena may occur.Normally,3%axial strain occurs before the"initial liquefaction"phenomenon and after that,strain increases obviously and pore pressure may reach the initial effective consolidation pressure.Sometimes the sample may be destroyed before the"initial liquefaction".3%axial strain is the critical point between being steady-state deformation and being large deformation.
Based on the result of saturated loess in dynamic triaxial test the 3%axial strain is put forward as the key parameter of the liquefaction criterion.The tests show:for the consolidated-undrained tests(CU)of the undisturbed loess, with increasing of the cycles,the structural bonding strength fades away and the volume shrinkage,which transforms into increasing of the pore pressure and decreasing of the effective stress.At last,the"initial liquefaction"and"cyclic activity" phenomena may occur.Normally,3%axial strain occurs before the"initial liquefaction"phenomenon and after that,strain increases obviously and pore pressure may reach the initial effective consolidation pressure.Sometimes the sample may be destroyed before the"initial liquefaction".3%axial strain is the critical point between being steady-state deformation and being large deformation.
引文
[1]王兰民,石玉成,刘旭等.黄土动力学[M].北京:地震出版社,2003.
[2]PRAKASH S,PURI,V.K.LIQUEFACTION OF LOESSIAL SOILS[C]//PROCEEDINGS OF THE THIRD INTERNATIONAL EARTHQUAKE MICROZONATION CONFERENCE,SEATTLE,WASHINGTON:VOL.II,PP.1101-7.1982.
[3]ISHIHARA K,OKUSA S,OYAGI N,ISCHUK.LIQUFACTION-INDUCED FLOW SLIDE IN THE COLLAPSIVE LOESS DEPOSIT IN SOVIET TAJIK[J].SOILS AND FOUNDATIONS,1990,30(4):73-89.
[4]白铭学,张苏民.高烈度地震时黄土地层的液化移动[J].工程勘察,1990,(6):1-5.
[5]杨振茂,赵成刚,王兰民,等.饱和黄土液化及其理论研究现状[J].土木工程学报,2003,36(11):89-94.
[6]袁中夏,王兰民,SUSUMU YASUDA,等.2004.黄土液化机理和判别标准的再研究[J].地震工程与工程振动.24(4):164-169.
[7]石兆吉,王兰民.土壤动力特性.液化势及危害性评价[M].北京:地震出版社,1999.
[8]佘跃心,刘汉龙,高玉峰.饱和黄土孔压增长模式与液化机理的试验研究[J].岩土力学,2002,23(4):395-399.
[9]刘公社,巫志辉.动荷载下饱和黄土的孔压演化规律及其在地基动力分析中的应用[J].工业建筑,1994,(3):40-44.
[10]ANNUAL BOOK OF ASTM STANDARDS,SOIL AND ROCK(1),AMERICAN SOCIETY FOR TESTING AND MATERIALS[M].WEST CONSHOHOCKEN,PA.1998.
[11]BRITISH STANDARD,SOILS FOR CIVIL ENGINEERING PURPOSES-PART 8:SHEAR STRENGTH TESTS(EFFECTIVE STRESS)[M].BRITISH STANDARDS INSTITUTION.
[12]STEPHEN KING.SOFTWARE REFERENCE MANUAL[R].INDUSTRIAL PROCESS CONTROLS GLOBAL LTD(IPC).BORONIA.2006.
[13]南京水利科学研究院.土工试验规程.SL237-1999[S].北京:中国水利水电出版社,1999.
[14]孙海妹.兰州黄土液化特性的试验研究[D].兰州:中国地震局兰州研究所.2009.
[15]孙海妹,王兰民,刘红玫,等.原状黄土的反压饱和法试验研究[J].防灾减灾工程学报,2010,30(1):98-102.
[16]孙海妹,王兰民,王平,等.饱和兰州黄土液化过程中孔压和应变发展的试验研究[J].岩土力学,2010,31(11):3464-3468.
[17]王兰民,刘红玫,李兰,等.饱和黄土液化机理与特性的试验研究[J].岩土工程学报.2000.22(1):89-94.
[2]PRAKASH S,PURI,V.K.LIQUEFACTION OF LOESSIAL SOILS[C]//PROCEEDINGS OF THE THIRD INTERNATIONAL EARTHQUAKE MICROZONATION CONFERENCE,SEATTLE,WASHINGTON:VOL.II,PP.1101-7.1982.
[3]ISHIHARA K,OKUSA S,OYAGI N,ISCHUK.LIQUFACTION-INDUCED FLOW SLIDE IN THE COLLAPSIVE LOESS DEPOSIT IN SOVIET TAJIK[J].SOILS AND FOUNDATIONS,1990,30(4):73-89.
[4]白铭学,张苏民.高烈度地震时黄土地层的液化移动[J].工程勘察,1990,(6):1-5.
[5]杨振茂,赵成刚,王兰民,等.饱和黄土液化及其理论研究现状[J].土木工程学报,2003,36(11):89-94.
[6]袁中夏,王兰民,SUSUMU YASUDA,等.2004.黄土液化机理和判别标准的再研究[J].地震工程与工程振动.24(4):164-169.
[7]石兆吉,王兰民.土壤动力特性.液化势及危害性评价[M].北京:地震出版社,1999.
[8]佘跃心,刘汉龙,高玉峰.饱和黄土孔压增长模式与液化机理的试验研究[J].岩土力学,2002,23(4):395-399.
[9]刘公社,巫志辉.动荷载下饱和黄土的孔压演化规律及其在地基动力分析中的应用[J].工业建筑,1994,(3):40-44.
[10]ANNUAL BOOK OF ASTM STANDARDS,SOIL AND ROCK(1),AMERICAN SOCIETY FOR TESTING AND MATERIALS[M].WEST CONSHOHOCKEN,PA.1998.
[11]BRITISH STANDARD,SOILS FOR CIVIL ENGINEERING PURPOSES-PART 8:SHEAR STRENGTH TESTS(EFFECTIVE STRESS)[M].BRITISH STANDARDS INSTITUTION.
[12]STEPHEN KING.SOFTWARE REFERENCE MANUAL[R].INDUSTRIAL PROCESS CONTROLS GLOBAL LTD(IPC).BORONIA.2006.
[13]南京水利科学研究院.土工试验规程.SL237-1999[S].北京:中国水利水电出版社,1999.
[14]孙海妹.兰州黄土液化特性的试验研究[D].兰州:中国地震局兰州研究所.2009.
[15]孙海妹,王兰民,刘红玫,等.原状黄土的反压饱和法试验研究[J].防灾减灾工程学报,2010,30(1):98-102.
[16]孙海妹,王兰民,王平,等.饱和兰州黄土液化过程中孔压和应变发展的试验研究[J].岩土力学,2010,31(11):3464-3468.
[17]王兰民,刘红玫,李兰,等.饱和黄土液化机理与特性的试验研究[J].岩土工程学报.2000.22(1):89-94.
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