主应力轴循环旋转下高密实粉土稳定性影响研究
|
摘要
为研究主应力轴循环旋转对粉土性状影响,对长江入海口高密实饱和粉土进行了主应力轴180°转幅的循环旋转试验。试验发现,等向固结的高密实粉土在恒定动剪应力比的主应力轴循环旋转下能发生孔压达到初始围压水平的液化破坏,但液化前孔压开展会因动应力水平的不同而呈现以渐变相态点和激变相态点区分的3阶段变化形式,或仅以激变相态点区分的两阶段变化形式。试样应变开展则始终呈现由崩塌点区分的两阶段变化形式,且孔压激变相态点与应变崩塌点同步反映了土体结构崩塌状态,崩塌状态时主应变差双向幅值限制在0.2%～0.4%这一较小范围内。试样进行主应力轴旋转达到崩塌时的应力状态与频率无显著关系,可由p′-q空间中一条准不稳定状态线归一化。而以崩塌状态为终点进行归一化的主应力轴循环旋转下孔压振次曲线,可用修正的Seed公式进行较好拟合。
Hollow cylinder samples tests were performed with high-density saturated silt from the sea entrance of the Yangtze River.The stress paths consisted of undrained cyclic principal stress rotation at the range of 180° with different shear stress ratio and frequency.It is found that isotropic consolidated samples would liquefy after cyclic principal stress axis rotation,which is featured by the excess pore water pressure reached initial effective confining pressure.Before the liquefaction,due to the different shear stress levels the development of pore water pressure was divided into three stages by graded phase transformation point and cataclysmic phase transformation point or two stages by cataclysmic phase transformation point.As for the development of strain components,it was divided into two stages by collapse point.Meanwhile the cataclysmic phase transformation point of pore water pressure and the collapse point of strain occurred simultaneously,which reflected the state of structure collapse.Besides the deviator strains when the collapse state occured were limited within a narrow range of 0.2%-0.4%.The stress state of collapse can be normalized in-space with a line when samples underwent cyclic principal stress axis rotation after isotropic consolidation.Furthermore the development of pore water pressure can be fitted well by modified Seed model in which the collapse state was used as the normalized denominator.
Hollow cylinder samples tests were performed with high-density saturated silt from the sea entrance of the Yangtze River.The stress paths consisted of undrained cyclic principal stress rotation at the range of 180° with different shear stress ratio and frequency.It is found that isotropic consolidated samples would liquefy after cyclic principal stress axis rotation,which is featured by the excess pore water pressure reached initial effective confining pressure.Before the liquefaction,due to the different shear stress levels the development of pore water pressure was divided into three stages by graded phase transformation point and cataclysmic phase transformation point or two stages by cataclysmic phase transformation point.As for the development of strain components,it was divided into two stages by collapse point.Meanwhile the cataclysmic phase transformation point of pore water pressure and the collapse point of strain occurred simultaneously,which reflected the state of structure collapse.Besides the deviator strains when the collapse state occured were limited within a narrow range of 0.2%-0.4%.The stress state of collapse can be normalized in-space with a line when samples underwent cyclic principal stress axis rotation after isotropic consolidation.Furthermore the development of pore water pressure can be fitted well by modified Seed model in which the collapse state was used as the normalized denominator.
引文
[1]CASAGRANDE A.Characteristics of cohesionless soilsaffecting the stability of slopes and earth fills[J].Journalof the Boston Society of Civil Engineers,1936,23(1):257-275.
[2]SEED H B,LEE K L.Liquefaction of saturated sandsduring cyclic loading[J].Journal of the Soil Mechanicsand Foundations Division,ASCE,1966,92(6):105-134.
[3]丰土根.饱和砂土不排水动力特性及多机构边界面塑性模型研究[D].南京:河海大学,2002.
[4]CASTRO G,POULOS S J.Factors affecting liquefactionand cyclic mobility[J].Journal of the GeotechnicalEngineering Division,ASCE,1977,103(6):501-516.
[5]CASTRO G.Liquefaction and cyclic mobility of satuatedsand[J].Journal of Geotechnical Engineering Division,ASCE,1974,101(6):555-569.
[6]ALARCON-GUZMAN A,LEONARDS G A,CHAMEAUJ L.Undrained monotonic and cyclic strength of sands[J].Journal of Geotechnieering Engineering,ASCE,1988,114(10):1089-1108.
[7]HYODO M,TANIMIZU H,YASUFUKU N,et al.Undrained cyclic and monotonic triaxial behaviour ofsaturated loose sand[J].Soils and Foundations,1994,34(1):19-32.
[8]GEORGIANNOU V N,TSOMOKOS A,STAVROU K.Monotonic and cyclic behaviour of sand under torsionalloading[J].Geotechnique,2008,58(2):113-124.
[9]石兆吉,郁寿松,王余庆,等.饱和轻亚黏土地基液化可能性判别[J].地震工程与工程振动,1984,4(3):71-82.SHI Zhao-ji,YU Shou-song,WANG Yu-qing,et al.Prediction of liquefaction potental of saturated clayeysilt[J].Earthquake Engineering and EngineeringVibration,1984,4(3):71-82.
[10]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,2006,26(增刊):83-87.LIU Hong-jun,WANG Xiao-hua,JIA Yong-gang,et al.Experimental study on liquefaction properties andpore-water pressure model of saturated silt in yellow riverdalta[J].Rock and Soil Mechanics,2006,26(Supp.):83-87.
[11]严栋,蒋关鲁,刘先峰,等.京沪高速铁路饱和粉土液化特性试验研究[J].岩土力学,2008,29(12):3337-3341.YAN Dong,JIANG Guan-lu,LIU Xian-feng,et al.Experimental research on liquefaction behavior ofsaturated silt for Beijing-Shanghai High-speed Railway[J].Rock and Soil Mechanics,2008,29(12):3337-3341.
[12]ISHIHARA K,TOWHATA I.Sand response to cyclicrotation of principal stress directions as induced by waveloads[J].Soils and Foundations,1983,23(4):11-26.
[13]TOWHATA I,ISHIHARA K.Undrained strength of sandundergoing cyclic rotation of principal stress axes[J].Soilsand Foundations,1985,25(2):135-147.
[14]LEONARDS G A,CHANG M F,DEWEY R.Discussionof“yielding of weathered Bangkok clay”[J].Soils andFoundations,1981,21(2):129-131.
[15]LADE P V.Initiation of static instability in the sub marineNerlerk berm[J].Canadian Geotechnical Journal,1993,30(6):895-904.
[16]ISHIHARA K,TATSUOKA F,YASUDA S.Undraineddeforrmation and liquefaction of sand under cyclicstresses[J].Soils and Foundations,1975,15(1):29-44.
[17]SEED H B,LYSMER J,MARTIN P P.Pore waterpressure changes during soil liquefaction[J].Journal ofthe Geotechnical Engineering Division,ASCE,1976,112(4):327-346.
[18]曹宇春,王天龙.上海粉土液化特性及孔压模型的试验研究[J].上海地质,1998,67(3):60-64.CAO Yu-chun,WANG Tian-long.Experimental study onliquefaction behavior and pore pressure model of silt inshanghai[J].Shanghai Geology,1998,67(3):60-64.
[19]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 porewater pressure in silty clay inter bedded with fine sandofnanjing[J].Chinese Journal of GeotechnicalEngineering,2004,26(1):79-82.
[2]SEED H B,LEE K L.Liquefaction of saturated sandsduring cyclic loading[J].Journal of the Soil Mechanicsand Foundations Division,ASCE,1966,92(6):105-134.
[3]丰土根.饱和砂土不排水动力特性及多机构边界面塑性模型研究[D].南京:河海大学,2002.
[4]CASTRO G,POULOS S J.Factors affecting liquefactionand cyclic mobility[J].Journal of the GeotechnicalEngineering Division,ASCE,1977,103(6):501-516.
[5]CASTRO G.Liquefaction and cyclic mobility of satuatedsand[J].Journal of Geotechnical Engineering Division,ASCE,1974,101(6):555-569.
[6]ALARCON-GUZMAN A,LEONARDS G A,CHAMEAUJ L.Undrained monotonic and cyclic strength of sands[J].Journal of Geotechnieering Engineering,ASCE,1988,114(10):1089-1108.
[7]HYODO M,TANIMIZU H,YASUFUKU N,et al.Undrained cyclic and monotonic triaxial behaviour ofsaturated loose sand[J].Soils and Foundations,1994,34(1):19-32.
[8]GEORGIANNOU V N,TSOMOKOS A,STAVROU K.Monotonic and cyclic behaviour of sand under torsionalloading[J].Geotechnique,2008,58(2):113-124.
[9]石兆吉,郁寿松,王余庆,等.饱和轻亚黏土地基液化可能性判别[J].地震工程与工程振动,1984,4(3):71-82.SHI Zhao-ji,YU Shou-song,WANG Yu-qing,et al.Prediction of liquefaction potental of saturated clayeysilt[J].Earthquake Engineering and EngineeringVibration,1984,4(3):71-82.
[10]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,2006,26(增刊):83-87.LIU Hong-jun,WANG Xiao-hua,JIA Yong-gang,et al.Experimental study on liquefaction properties andpore-water pressure model of saturated silt in yellow riverdalta[J].Rock and Soil Mechanics,2006,26(Supp.):83-87.
[11]严栋,蒋关鲁,刘先峰,等.京沪高速铁路饱和粉土液化特性试验研究[J].岩土力学,2008,29(12):3337-3341.YAN Dong,JIANG Guan-lu,LIU Xian-feng,et al.Experimental research on liquefaction behavior ofsaturated silt for Beijing-Shanghai High-speed Railway[J].Rock and Soil Mechanics,2008,29(12):3337-3341.
[12]ISHIHARA K,TOWHATA I.Sand response to cyclicrotation of principal stress directions as induced by waveloads[J].Soils and Foundations,1983,23(4):11-26.
[13]TOWHATA I,ISHIHARA K.Undrained strength of sandundergoing cyclic rotation of principal stress axes[J].Soilsand Foundations,1985,25(2):135-147.
[14]LEONARDS G A,CHANG M F,DEWEY R.Discussionof“yielding of weathered Bangkok clay”[J].Soils andFoundations,1981,21(2):129-131.
[15]LADE P V.Initiation of static instability in the sub marineNerlerk berm[J].Canadian Geotechnical Journal,1993,30(6):895-904.
[16]ISHIHARA K,TATSUOKA F,YASUDA S.Undraineddeforrmation and liquefaction of sand under cyclicstresses[J].Soils and Foundations,1975,15(1):29-44.
[17]SEED H B,LYSMER J,MARTIN P P.Pore waterpressure changes during soil liquefaction[J].Journal ofthe Geotechnical Engineering Division,ASCE,1976,112(4):327-346.
[18]曹宇春,王天龙.上海粉土液化特性及孔压模型的试验研究[J].上海地质,1998,67(3):60-64.CAO Yu-chun,WANG Tian-long.Experimental study onliquefaction behavior and pore pressure model of silt inshanghai[J].Shanghai Geology,1998,67(3):60-64.
[19]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 porewater pressure in silty clay inter bedded with fine sandofnanjing[J].Chinese Journal of GeotechnicalEngineering,2004,26(1):79-82.
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