饱和层状砂土液化特性的动三轴试验研究
|
摘要
利用GDS动三轴试验系统采用等幅循环应变加载方式对含有不同厚度粉土的饱和层状砂土进行了液化强度试验。分析了均匀砂和含有不同粉粒层厚度的层状砂土在循环荷载作用下的变形和力学特性。试验分析表明:由于含粉粒夹层的层状土特殊的土体结构,其孔隙水压力发展规律与一般的无黏性砂土不同;饱和层状砂土的抗液化强度并不是随着粉粒层厚度的增加而单调增加的,而是存在一个临界点;液化临界剪应变的大小与液化判别标准和循环次数有很大关系。试验结果表明,粉粒夹层对层状砂土的液化特性有很大的影响,且更能模拟自然环境条件下的层状砂土地基液化特性。
Liquefaction strength tests for saturated stratified sands with different silty layer thicknesses were carried out by dynamic triaxial testing machine under constant stress amplitude cyclic loads.The deformation and mechanical properties for clean sand and stratified sand with different silty layer thickness were analyzed.The experimental results show that the development law of pore water pressure for stratified silty sands are different from clean sands due to the special soil structure;the liquefaction resistance strength of saturated stratified silty sands does not increase monotonously with the thickness of silty soil layer,but there is a critical thickness.However,the liquefaction resistance strength increases monotonously with the thickness increasing above the critical point;the critical shear strains are different under different liquefaction criteria and different cycle numbers,such as the critical shear strain under the criterion of =1.0 is larger than that under the criterion of =0.9.Besides,the critical shear strain should not be a constant under different earthquake magnitude and intensity.The silty interlayers influence the liquefaction characteristics of stratified silty sands greatly and can simulate the liquefaction characteristics of stratified sands in natural environment better.
Liquefaction strength tests for saturated stratified sands with different silty layer thicknesses were carried out by dynamic triaxial testing machine under constant stress amplitude cyclic loads.The deformation and mechanical properties for clean sand and stratified sand with different silty layer thickness were analyzed.The experimental results show that the development law of pore water pressure for stratified silty sands are different from clean sands due to the special soil structure;the liquefaction resistance strength of saturated stratified silty sands does not increase monotonously with the thickness of silty soil layer,but there is a critical thickness.However,the liquefaction resistance strength increases monotonously with the thickness increasing above the critical point;the critical shear strains are different under different liquefaction criteria and different cycle numbers,such as the critical shear strain under the criterion of =1.0 is larger than that under the criterion of =0.9.Besides,the critical shear strain should not be a constant under different earthquake magnitude and intensity.The silty interlayers influence the liquefaction characteristics of stratified silty sands greatly and can simulate the liquefaction characteristics of stratified sands in natural environment better.
引文
[1]AMINI F,QI G Z.Liquefaction testing of stratified silty sands[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2000,126(3):208-217.
[2]YOSHIMI Y,TOKIMATSU K,KANEKO O,et al.Undrained cyclic shear strength of a dense Niigata sand[J].Soils and Foundations,1984,24(4):131-145.
[3]YOSHIMI Y,TOKIMATSU K,HOSAKA Y.Evaluation of liquefaction resistance of clean sands based on high-quality undisturbed samples[J].Soils and Foundations,1989,29(1):93-104.
[4]BAZIAR M H,DOBRY R.Residual strength and large-deformation potential of loose silty sands[J].Journal of Geotechnical Engineering,ASCE,1995,121(12):896-906.
[5]PRADHAN T B S.Liquefaction behavior of sandy soil sandwiched by clay layers[C]//Proceedings of the 7th(1997)International Offshore and Polar Engineering.Honolulu,HI,USA:International Society of Offshore and Polar Engineers(ISOPE),1997:676-682.
[6]AMINI F,QI G Z.Liquefaction testing of stratified silty sands[J].Journal of Geotechnical and Geoenviron-mental Engineering,ASCE,2000,126(3):208-217.
[7]YOSHIMINE M,KOIKE R.Liquefaction of clean sand with stratified structure due to segregation of particle size[J].Soils and Foundations,2005,45(4):89-98.
[8]OZENER P T,OZAYDIN K,BERILGEN M.Numerical and physical modeling of liquefaction mechanisms in layered sands[C]//Proceedings of the Geotechnical Earthquake Engineering and Soil Dynamics IV Congress 2008.Sacramento,CA,United States:American Society of Civil Engineers,2008:318-328.
[9]刘颖,谢君斐.砂土振动液化[M].北京:地震出版社,1984.
[10]石兆吉.循环等幅应变作用下砂土中孔隙水压力的变化规律[C]//全国土工建筑物及地基抗震会议论文汇编.西安:[s.n.],1986:69-73.
[11]SITHARAM T G,GOVINDA RAJU L,SRINIVASA MURTHY B R.Cyclic and monotonic undrained shear response of silty sand from Bhuj region in India[J].Journal of Earthquake Technology,2004,41(6-12):249-260.
[12]周健,杨永香,刘洋.循环荷载下砂土液化特性颗粒流数值模拟[J].岩土力学,2009,30(4):1083-1088.ZHOU Jian,YANG Yong-xiang,LIU Yang.Numerical modeling of sand liquefaction behavior under cyclic loading[J].Rock and Soil Mechanics,2009,30(4):1083-1088.
[13]陈国兴,刘雪珠,庄海洋.南京粉质粘土与粉砂互层土及粉细砂的抗液化性能试验研究[J].防灾减灾工程学报,2003,23(2):28-34.CHEN Guo-xing,LIU Xue-zhu,ZHUANG Hai-yang.Experimental study of liquefaction resistant characteristics of silty clay with fine sand interbed and fine sand in Nanjing[J].Journal of Disaster Prevention and Mitigation Engineering,2003,23(2):28-34.
[2]YOSHIMI Y,TOKIMATSU K,KANEKO O,et al.Undrained cyclic shear strength of a dense Niigata sand[J].Soils and Foundations,1984,24(4):131-145.
[3]YOSHIMI Y,TOKIMATSU K,HOSAKA Y.Evaluation of liquefaction resistance of clean sands based on high-quality undisturbed samples[J].Soils and Foundations,1989,29(1):93-104.
[4]BAZIAR M H,DOBRY R.Residual strength and large-deformation potential of loose silty sands[J].Journal of Geotechnical Engineering,ASCE,1995,121(12):896-906.
[5]PRADHAN T B S.Liquefaction behavior of sandy soil sandwiched by clay layers[C]//Proceedings of the 7th(1997)International Offshore and Polar Engineering.Honolulu,HI,USA:International Society of Offshore and Polar Engineers(ISOPE),1997:676-682.
[6]AMINI F,QI G Z.Liquefaction testing of stratified silty sands[J].Journal of Geotechnical and Geoenviron-mental Engineering,ASCE,2000,126(3):208-217.
[7]YOSHIMINE M,KOIKE R.Liquefaction of clean sand with stratified structure due to segregation of particle size[J].Soils and Foundations,2005,45(4):89-98.
[8]OZENER P T,OZAYDIN K,BERILGEN M.Numerical and physical modeling of liquefaction mechanisms in layered sands[C]//Proceedings of the Geotechnical Earthquake Engineering and Soil Dynamics IV Congress 2008.Sacramento,CA,United States:American Society of Civil Engineers,2008:318-328.
[9]刘颖,谢君斐.砂土振动液化[M].北京:地震出版社,1984.
[10]石兆吉.循环等幅应变作用下砂土中孔隙水压力的变化规律[C]//全国土工建筑物及地基抗震会议论文汇编.西安:[s.n.],1986:69-73.
[11]SITHARAM T G,GOVINDA RAJU L,SRINIVASA MURTHY B R.Cyclic and monotonic undrained shear response of silty sand from Bhuj region in India[J].Journal of Earthquake Technology,2004,41(6-12):249-260.
[12]周健,杨永香,刘洋.循环荷载下砂土液化特性颗粒流数值模拟[J].岩土力学,2009,30(4):1083-1088.ZHOU Jian,YANG Yong-xiang,LIU Yang.Numerical modeling of sand liquefaction behavior under cyclic loading[J].Rock and Soil Mechanics,2009,30(4):1083-1088.
[13]陈国兴,刘雪珠,庄海洋.南京粉质粘土与粉砂互层土及粉细砂的抗液化性能试验研究[J].防灾减灾工程学报,2003,23(2):28-34.CHEN Guo-xing,LIU Xue-zhu,ZHUANG Hai-yang.Experimental study of liquefaction resistant characteristics of silty clay with fine sand interbed and fine sand in Nanjing[J].Journal of Disaster Prevention and Mitigation Engineering,2003,23(2):28-34.
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