饱和层状砂土三轴液化试验
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摘要
为了研究具有层状结构的饱和砂土液化时孔隙水压力的发展规律,利用GCTS-STX-050气动三轴测试系统对层状饱和砂土进行等幅应变控制下的液化试验研究,分析了试样中不同粉粒夹层厚度、位置及分布层数对液化影响.试验结果表明,试样液化所需的循环加载次数与粉粒夹层的厚度呈非线性关系,存在一临界厚度使得循环加载次数最大;粉粒层能够有效地阻碍细粒层产生的超孔隙水压力的传递,而细粒层对粉粒层产生的超孔隙水压力阻碍效果不明显;相同厚度下,粉粒夹层两层分布较一层分布对超孔隙水压力的阻碍作用更加明显.试验结论可为地震作用下具有层状结构的饱和砂土液化规律的探索提供一定的参考依据.
In order to study the developments of pore water pressure in the liquefaction processes of saturated sands with stratified structure,the liquefaction tests under equal amplitude strain control for saturated sands were carried out by using GCTS-STX-050 dynamic triaxial testing system. The effect of different thickness,position and number of layers on liquefaction was analyzed. It is showed that the cyclic loading times required for liquefaction is non-linearly related to the thickness of the silt interlayer. There is a critical thickness that causes the cyclic loading times to be maximum. And the silt can effectively prevent the transfer of excess pore water pressure generated by fine sand. But the inhibition of fine sand for excess pore water pressure generated by silt is not obvious. Under the same thickness of silt interlayer,the distribution of two-layered interlayer is more obvious than one layer on obstruction of excess pore water pressure.The conclusion can provide a reference for the liquefaction of saturated sand with stratified structure under earthquake.
In order to study the developments of pore water pressure in the liquefaction processes of saturated sands with stratified structure,the liquefaction tests under equal amplitude strain control for saturated sands were carried out by using GCTS-STX-050 dynamic triaxial testing system. The effect of different thickness,position and number of layers on liquefaction was analyzed. It is showed that the cyclic loading times required for liquefaction is non-linearly related to the thickness of the silt interlayer. There is a critical thickness that causes the cyclic loading times to be maximum. And the silt can effectively prevent the transfer of excess pore water pressure generated by fine sand. But the inhibition of fine sand for excess pore water pressure generated by silt is not obvious. Under the same thickness of silt interlayer,the distribution of two-layered interlayer is more obvious than one layer on obstruction of excess pore water pressure.The conclusion can provide a reference for the liquefaction of saturated sand with stratified structure under earthquake.
引文
[1] Peyman A,Ali P. Liquefaction-induced settlement of shallow foundations on two-layered subsoil strata[J]. Soil Dynamics and Earthquake Engineering,2017,94:35-46.
[2]周健，陈小亮，杨永香，等．饱和层状砂土液化特性的动三轴试验研究[J]．岩土力学，2011,32(4):967-972,978.(Zhou Jian,Chen Xiao-liang,Yang Yong-xiang,et al. Study of liquefaction characteristics of saturated stratified sands by dynamic triaxial test[J]. Rock and Soil Mechanics,2011,32(4):967-972,978.)
[3] Amini F,Qi G Z. Liquefaction testing of stratified silty sands[J]. Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2000,126(3):208-217.
[4] Kim J,Kawai T,Kazama M. Laboratory testing procedure to assess post-liquefaction deformation potential[J]. Soils and Foundations,2017,57:905-919.
[5] Takch A E,Sadrekarimi A,Naggar H E. Cyclic resistance and liquefaction behavior of silt and sandy silt soils[J]. Soil Dynamics and Earthquake Engineering,2016,83:98-109.
[6] Wang Y,Wang Y L. Liquefaction characteristics of gravelly soil under cyclic loading with constant strain amplitude by experimental and numerical investigations[J]. Soil Dynamics and Earthquake Engineering,2017,92:388-396.
[7] Karamitros D K,Bouckovalas G D,Chaloulos Y K,et al.Numerical analysis of liquefaction-induced bearing capacity degradation of shallow foundations on a two-layered soil profile[J]. Soil Dynamics and Earthquake Engineering,2013,44:90-101.
[8] Evans M D,Zhou S. Liquefaction behavior of sand-gravel composites[J]. Journal of G eotechnical Engineering,1995,121(3):287-298.
[9] Chang W J, Chang C W, Zeng J K. Liquefaction characteristics of gap-graded gravelly soils in K0,condition[J]. Soil Dynamics and Earthquake Engineering,2014,56:74-85.
[10] Praghan T B S. Liquefaction behavior of sandy soil sandwiched by clay layers[C]//Proceedings of the 7th International Offshore and Polar Engineering. Honolulu:International Society of Offshore and Polar Engineers(ISOPE),1997:676-682.
[11] 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.
[12] Ozener P T,Ozaydin K,Berrilgen 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:American Society of Civil Engineers,2008:318-328.
[13]陈国兴，刘雪珠．南京粉质黏土与粉砂互层土及粉细砂的振动孔压发展规律研究[J]．岩土工程学报，2004,26(1):79-82.(Chen Guo-xing,Liu Xue-zhu. Study on dynamic pore water pressure in silty clay interbedded with fine sand of Nanjing[J]. Chinese Journal of Geotechnical Engineering,2004,26(1):79-82.)
[14]修占国．大型基础下层状地基土的变形计算及液化分析[D]．沈阳:东北大学，2017.(Xiu Zhan-guo. Study on the deformation calculation and liquefaction of layered soil under large building foundation[D]. Shenyang:Northeastern University,2017.)
[15]潘华，陈国兴，刘汉龙．饱和南京细砂液化后大变形特性试验研究[J]．岩石力学与工程学报，2011,30(7):1475-1481.(Pan Hua,Chen Guo-xing,Liu Han-long. Study of behaviour of large post-liquefaction deformation in saturated Nanjing fine sand[J]. Chinese Journal of Rock Mechanics and Engineering,2011,30(7):1475-1481.)
[2]周健，陈小亮，杨永香，等．饱和层状砂土液化特性的动三轴试验研究[J]．岩土力学，2011,32(4):967-972,978.(Zhou Jian,Chen Xiao-liang,Yang Yong-xiang,et al. Study of liquefaction characteristics of saturated stratified sands by dynamic triaxial test[J]. Rock and Soil Mechanics,2011,32(4):967-972,978.)
[3] Amini F,Qi G Z. Liquefaction testing of stratified silty sands[J]. Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2000,126(3):208-217.
[4] Kim J,Kawai T,Kazama M. Laboratory testing procedure to assess post-liquefaction deformation potential[J]. Soils and Foundations,2017,57:905-919.
[5] Takch A E,Sadrekarimi A,Naggar H E. Cyclic resistance and liquefaction behavior of silt and sandy silt soils[J]. Soil Dynamics and Earthquake Engineering,2016,83:98-109.
[6] Wang Y,Wang Y L. Liquefaction characteristics of gravelly soil under cyclic loading with constant strain amplitude by experimental and numerical investigations[J]. Soil Dynamics and Earthquake Engineering,2017,92:388-396.
[7] Karamitros D K,Bouckovalas G D,Chaloulos Y K,et al.Numerical analysis of liquefaction-induced bearing capacity degradation of shallow foundations on a two-layered soil profile[J]. Soil Dynamics and Earthquake Engineering,2013,44:90-101.
[8] Evans M D,Zhou S. Liquefaction behavior of sand-gravel composites[J]. Journal of G eotechnical Engineering,1995,121(3):287-298.
[9] Chang W J, Chang C W, Zeng J K. Liquefaction characteristics of gap-graded gravelly soils in K0,condition[J]. Soil Dynamics and Earthquake Engineering,2014,56:74-85.
[10] Praghan T B S. Liquefaction behavior of sandy soil sandwiched by clay layers[C]//Proceedings of the 7th International Offshore and Polar Engineering. Honolulu:International Society of Offshore and Polar Engineers(ISOPE),1997:676-682.
[11] 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.
[12] Ozener P T,Ozaydin K,Berrilgen 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:American Society of Civil Engineers,2008:318-328.
[13]陈国兴，刘雪珠．南京粉质黏土与粉砂互层土及粉细砂的振动孔压发展规律研究[J]．岩土工程学报，2004,26(1):79-82.(Chen Guo-xing,Liu Xue-zhu. Study on dynamic pore water pressure in silty clay interbedded with fine sand of Nanjing[J]. Chinese Journal of Geotechnical Engineering,2004,26(1):79-82.)
[14]修占国．大型基础下层状地基土的变形计算及液化分析[D]．沈阳:东北大学，2017.(Xiu Zhan-guo. Study on the deformation calculation and liquefaction of layered soil under large building foundation[D]. Shenyang:Northeastern University,2017.)
[15]潘华，陈国兴，刘汉龙．饱和南京细砂液化后大变形特性试验研究[J]．岩石力学与工程学报，2011,30(7):1475-1481.(Pan Hua,Chen Guo-xing,Liu Han-long. Study of behaviour of large post-liquefaction deformation in saturated Nanjing fine sand[J]. Chinese Journal of Rock Mechanics and Engineering,2011,30(7):1475-1481.)