饱和兰州黄土液化过程中孔压和应变发展的试验研究
|
摘要
采用WF12440型空心圆柱扭剪仪,用反压饱和法对初始饱和度较低的原状黄土进行饱和,进行室内原状黄土饱和液化试验研究,探讨了饱和兰州黄土液化过程中孔隙水压力、轴向应变、应力-应变滞回圈的发展规律。结果表明,对初始饱和度较低的原状黄土,反压饱和法使孔压系数B值达到0.95以上,即土样完全饱和;兰州黄土在均压固结条件下液化的孔压发展,开始时上升速率较缓慢,循环数一定后会出现孔压迅速增高的现象直至达到有效围压;应力-应变滞回特性随着振动次数的增加发生变化,塑性逐步增大;当轴向应变小于2%时,孔压增长缓慢;此后,孔压上升速率加大,3%应变可以出现在初始液化前;接近液化时偏应力为负值时的有效应力大于正值时的有效应力。
Using a dynamic hollow cylinder apparatus WF12440 as the test platform,this paper firstly studied the loess saturation by the back pressure method.The developments of pore water pressure,axial strain,deviatoric stress-axial strain curve during liquefaction are then investigated.Testing results indicate that the back pressure method can be successfully used for loess saturation;and the pore water pressure coefficient could achieve 0.95 and more.Under the condition of isotropic consolidation,pore water pressure increased slowly at the beginning;after several cycles the pore water pressure increased rapidly until it reached the effective consolidation pressure.The deviatoric stress-axial strain curve developed with the increase of cycles;and plastic strain increased step by step.When the axial strain was less than 2%,the pore water pressure increased slowly;afterwards,its increase ratio was much larger,and a strain of 3% could appear at the initial liquefaction process.Before liquefaction of the loess,the mean effective stress under negative deviatoric stress is larger than that under the positive deviatoric stress.
Using a dynamic hollow cylinder apparatus WF12440 as the test platform,this paper firstly studied the loess saturation by the back pressure method.The developments of pore water pressure,axial strain,deviatoric stress-axial strain curve during liquefaction are then investigated.Testing results indicate that the back pressure method can be successfully used for loess saturation;and the pore water pressure coefficient could achieve 0.95 and more.Under the condition of isotropic consolidation,pore water pressure increased slowly at the beginning;after several cycles the pore water pressure increased rapidly until it reached the effective consolidation pressure.The deviatoric stress-axial strain curve developed with the increase of cycles;and plastic strain increased step by step.When the axial strain was less than 2%,the pore water pressure increased slowly;afterwards,its increase ratio was much larger,and a strain of 3% could appear at the initial liquefaction process.Before liquefaction of the loess,the mean effective stress under negative deviatoric stress is larger than that under the positive deviatoric stress.
引文
[1]王兰民.随机地震荷载作用下黄土液化的试验预测[C]//第四届全国土动力学学术会议论文集.杭州:浙江大学出版社,1994:134-137.
[2]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.
[3]刘汉龙,佘跃心,王兰民.强夯黄土地基液化试验研究[C]//土动力学与岩土地震工程.北京:中国建筑工业出版社,2002.
[4]GUO T Q,PRAKASH S.Liquefaction of silts and silt-clay mixtures[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,1999,125(8):706-710.
[5]ISHIHARA K,OKUSA S,OYAGI N,et al.Liquefaction-induced flow slide in the collapsible loess deposit in Soviet Tajik[J].Soils and Foundations,1990,30(4):73-89.
[6]石兆吉,王兰民.土壤动力特性[M]//液化势及危害性评价.北京:地震出版社,1999.
[7]王兰民,刘红玫,李兰,等.饱和黄土液化机制与特性的试验研究[J].岩土工程学报,2000,22(1):89-94.WANG Lan-min,LIU Hong-mei,LI Lan,et al.Laboratory study on the mechanism and behaviors of saturated loess liquefaction[J].Chinese Journal of Geotechnical Engineering,2000,22(1):89-94.
[8]王兰民,石玉成,刘旭,等.黄土动力学[M].北京:地震出版社,2003.
[9]PRAKASH S,PURI V K.Liquefaction of loessial soils[C]//Proceedings of Third International Conference.[S.l.]:[s.n.],1982:l101-l107.
[10]PURI V K.Liquefaction behavior and dynamic properties of loessial(silty)soils[D].Missouri:University of Missouri ro11a,l984.
[11]SHANNON S.Liquefaction and settlement characteristics of silt soils[M].Mo.U.S:University of Missouri-Rolla,1989.
[12]凌华,殷宗泽,蔡正银.非饱和土的应力-含水率-应变关系试验研究[J].岩土力学,2008,29(3):651-655.LING Hua,YIN Zong-ze,CAI Zheng-yin.Experimental study on stress-water content-strain relationship of unsaturated soil[J].Rock and Soil Mechanics,2008,29(3):651-655.
[13]ASTM.Soil and rock(1)[S]//American Society for Testing and Materials.U.S.A:West Conshohocken,PA,1998
[14]British Standards Institution.Soils for civil engineering purposes(Part8):Shear strength tests(effective stress)[S].London:British Standards Institution,1990.
[15]STEPHEN King.Software reference manual[R].Boronia:Industrial Process Controls Global Ltd(IPC),2006.
[16]南京水利科学研究院.SL237-1999土工试验规程[S].北京:中国水利水电出版社,1999.
[17]刘红军,王小花,贾永刚,等.黄河三角洲饱和粉土液化特性及孔压模型试验研究[J].岩土力学,2005,26(10):83-87.LIU Hong-jun,WANG Xiao-hua,JIA Yong-gang,et al.Experimental study on liquefaction properties and pore-water pressure model of saturated silt in Yellow River Delta[J].Rock and Soil Mechanics,2005,26(10):83-87.
[2]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.
[3]刘汉龙,佘跃心,王兰民.强夯黄土地基液化试验研究[C]//土动力学与岩土地震工程.北京:中国建筑工业出版社,2002.
[4]GUO T Q,PRAKASH S.Liquefaction of silts and silt-clay mixtures[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,1999,125(8):706-710.
[5]ISHIHARA K,OKUSA S,OYAGI N,et al.Liquefaction-induced flow slide in the collapsible loess deposit in Soviet Tajik[J].Soils and Foundations,1990,30(4):73-89.
[6]石兆吉,王兰民.土壤动力特性[M]//液化势及危害性评价.北京:地震出版社,1999.
[7]王兰民,刘红玫,李兰,等.饱和黄土液化机制与特性的试验研究[J].岩土工程学报,2000,22(1):89-94.WANG Lan-min,LIU Hong-mei,LI Lan,et al.Laboratory study on the mechanism and behaviors of saturated loess liquefaction[J].Chinese Journal of Geotechnical Engineering,2000,22(1):89-94.
[8]王兰民,石玉成,刘旭,等.黄土动力学[M].北京:地震出版社,2003.
[9]PRAKASH S,PURI V K.Liquefaction of loessial soils[C]//Proceedings of Third International Conference.[S.l.]:[s.n.],1982:l101-l107.
[10]PURI V K.Liquefaction behavior and dynamic properties of loessial(silty)soils[D].Missouri:University of Missouri ro11a,l984.
[11]SHANNON S.Liquefaction and settlement characteristics of silt soils[M].Mo.U.S:University of Missouri-Rolla,1989.
[12]凌华,殷宗泽,蔡正银.非饱和土的应力-含水率-应变关系试验研究[J].岩土力学,2008,29(3):651-655.LING Hua,YIN Zong-ze,CAI Zheng-yin.Experimental study on stress-water content-strain relationship of unsaturated soil[J].Rock and Soil Mechanics,2008,29(3):651-655.
[13]ASTM.Soil and rock(1)[S]//American Society for Testing and Materials.U.S.A:West Conshohocken,PA,1998
[14]British Standards Institution.Soils for civil engineering purposes(Part8):Shear strength tests(effective stress)[S].London:British Standards Institution,1990.
[15]STEPHEN King.Software reference manual[R].Boronia:Industrial Process Controls Global Ltd(IPC),2006.
[16]南京水利科学研究院.SL237-1999土工试验规程[S].北京:中国水利水电出版社,1999.
[17]刘红军,王小花,贾永刚,等.黄河三角洲饱和粉土液化特性及孔压模型试验研究[J].岩土力学,2005,26(10):83-87.LIU Hong-jun,WANG Xiao-hua,JIA Yong-gang,et al.Experimental study on liquefaction properties and pore-water pressure model of saturated silt in Yellow River Delta[J].Rock and Soil Mechanics,2005,26(10):83-87.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心