复杂应力路径下饱和粉土孔压与变形试验研究
|
摘要
为了研究均等固结条件下复杂应力路径(循环应力比CSR和循环加载幅值比δ)对饱和粉土孔压和变形的影响,利用GDS空心圆柱扭剪仪,开展了轴向-扭转耦合循环加载的重塑饱和粉土不排水试验。采用累积广义剪应变γg来描述粉土在复杂应力路径下的变形,并以γg=5%为液化破坏标准。研究表明:(1)未液化粉土γg的发展趋势可以通过修正Monismith模型较好地表示,模型得到的预测值与测量值的误差大致在10%以内。(2)当CSR≤0. 05时,CSR和δ对于粉土γg随孔压比ru增大而增大的影响不明显,此时粉土γg几乎不发展且ru远小于1. 0。(3)粉土在不同应力路径下的临界循环应力比CSRth有所不同,当δ=1时,0. 05 In order to study the influences of complex stress paths( cyclic stress ratio CSR and cyclic loading amplitude ratio δ) on the excess pore pressure and deformation of saturated silt under isotropic consolidation conditions.Using the GDS hollow cylinder apparatus,a series of undrained tests are performed on the remolded saturated silt under combined axial-torsional cyclic loading. The accumulative generalized shear strain γgis used to describe the deformation of the silt under complex stress paths,and take γg= 5% as the liquefaction triggering criteria. The test results show that:( 1) The development trend of γgcan be well expressed through the correct Monismith model in the non-liquefaction silt,and the deviation between the predicted values and the measured values is within 10%.( 2) When CSR≤0. 05,the influence of CSR and δ on the increase of excess pore pressure ratio ruand γgis not obvious. At this time,γgis almost not developed and ruwas far less than 1. 0 of silt.( 3) The threshold cyclic stress ratios CSRthare different under different stress paths,when δ = 1,0. 05 < CSRth≤0. 065 and δ = 2,0. 065
引文
[1] Yasuhara K,Murakami S,Song B W,et al. Post cyclic degradation of strength and stiffness for low plasticity silt[J]. Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2003,129(8):756-769.
[2]黄博,丁浩,陈云敏,等.交通荷载作用后粉质黏土不排水强度特性试验研究[J].岩石力学与工程学报,2010,29(增刊2):3986-3993.HUANG Bo,DING Hao,CHEN Yunmin,et al. Experimental study of undrained strength property of saturated silty clay after traffic load[J]. Chinese Journal of Rock Mechanics and Engineering,2010,29(S2):3986-3993.(in Chinese)
[3]边学成,卢文博,蒋红光,等.粉土循环累积应变和残余动模量的试验研究[J].岩土力学,2013,34(4):961-966.BIAN Xuecheng,LU Wenbo,JIANG Hongguang,et al. Experimental study of cumulative axial strain and residual dynamic modulus of silt soil[J]. Rock and Soil Mechanics,2013,34(4):961-966.(in Chinese)
[4] Monismith C L,Ogawa N,Freeme C R. Permanent deformation characteristics of subgrade soils due to repeated loading[J]. Transportation ResearchRecord,1975,537:1-17.
[5] Gidel G,Hornych P,Chauvin J,et al. A new approach for investigating the permanent deformation behavior of unbound granular material using the repeated load triaxial apparatus[J]. Bulletin des Laboratoires des Ponts et Chaussees,2001,6(8):5-21.
[6]王军,蔡袁强.循环荷载作用下饱和软黏土应变累积模型研究[J].岩石力学与工程学报,2008,27(2):331-338.WANG Jun,CAI Yuanqiang. Study on accumulative plastic strain model of soft clay under cyclic loading[J]. Chinese Journal of Rock Mechanics and Engineering,2008,27(2):331-338.(in Chinese)
[7] Guo L,Chen J,Wang J,et al. Influences of stress magnitude and loading frequency on cyclic behavior of K0-consolidated marine clay involving principal stress rotation[J]. Soil Dynamics and Earthquake Engineering,2016,84:94-107.
[8]周正龙,陈国兴,吴琪.四向振动空心圆柱扭剪仪模拟主应力轴旋转应力路径能力分析[J].岩土力学,2016,(增刊1):126-132.ZHOU Zhenglong,CHEN Guoxing,WU Qi. Analysis on capabilities of stress paths of HCA to simulate the principal stress rotation under four dynamic loads[J]. Rock and Soil Mechanics,2016,37(S1):126-132.(in Chinese)
[9]王立忠,潘冬子,凌道盛.海床波浪响应的积分变换解及其分析应用[J].岩土工程学报,2006,28(7):847-852.WANG Lizhong,PAN Dongzi,LING Daosheng. Analysis of integral transform of the wave-induced response in seabed and its application[J]. Chinese Journal of Geotechnical Engineering,2006,28(7):847-852.(in Chinese)
[10] Wang Y K,Gao Y,Guo L,et al. Cyclic response of natural soft marine clay under principal stress rotation as induced by wave loads[J]. Ocean Engineering,2017,129:191-202.
[11] Anderson K H. Bearing capacity under cyclic loading-offshore,along the coast,and on land[J]. Canadian Geotechnical Journal,2009,46(5):513-535.
[12] Xia K,Wang J. Shear principal,and equivalent strains in equal-channel angular deformation[J]. Metallurgical and Materials Transactions A,2002,33(2):467-467.
[13] Casagrande A. Liquefaction and cyclic deformation of sands:a critical review[C]//Proceedings of the 5th Pan-American Conference on Soil Mechanics and Foundation Engineering. Buenos Aires,Argentian,1975.
[2]黄博,丁浩,陈云敏,等.交通荷载作用后粉质黏土不排水强度特性试验研究[J].岩石力学与工程学报,2010,29(增刊2):3986-3993.HUANG Bo,DING Hao,CHEN Yunmin,et al. Experimental study of undrained strength property of saturated silty clay after traffic load[J]. Chinese Journal of Rock Mechanics and Engineering,2010,29(S2):3986-3993.(in Chinese)
[3]边学成,卢文博,蒋红光,等.粉土循环累积应变和残余动模量的试验研究[J].岩土力学,2013,34(4):961-966.BIAN Xuecheng,LU Wenbo,JIANG Hongguang,et al. Experimental study of cumulative axial strain and residual dynamic modulus of silt soil[J]. Rock and Soil Mechanics,2013,34(4):961-966.(in Chinese)
[4] Monismith C L,Ogawa N,Freeme C R. Permanent deformation characteristics of subgrade soils due to repeated loading[J]. Transportation ResearchRecord,1975,537:1-17.
[5] Gidel G,Hornych P,Chauvin J,et al. A new approach for investigating the permanent deformation behavior of unbound granular material using the repeated load triaxial apparatus[J]. Bulletin des Laboratoires des Ponts et Chaussees,2001,6(8):5-21.
[6]王军,蔡袁强.循环荷载作用下饱和软黏土应变累积模型研究[J].岩石力学与工程学报,2008,27(2):331-338.WANG Jun,CAI Yuanqiang. Study on accumulative plastic strain model of soft clay under cyclic loading[J]. Chinese Journal of Rock Mechanics and Engineering,2008,27(2):331-338.(in Chinese)
[7] Guo L,Chen J,Wang J,et al. Influences of stress magnitude and loading frequency on cyclic behavior of K0-consolidated marine clay involving principal stress rotation[J]. Soil Dynamics and Earthquake Engineering,2016,84:94-107.
[8]周正龙,陈国兴,吴琪.四向振动空心圆柱扭剪仪模拟主应力轴旋转应力路径能力分析[J].岩土力学,2016,(增刊1):126-132.ZHOU Zhenglong,CHEN Guoxing,WU Qi. Analysis on capabilities of stress paths of HCA to simulate the principal stress rotation under four dynamic loads[J]. Rock and Soil Mechanics,2016,37(S1):126-132.(in Chinese)
[9]王立忠,潘冬子,凌道盛.海床波浪响应的积分变换解及其分析应用[J].岩土工程学报,2006,28(7):847-852.WANG Lizhong,PAN Dongzi,LING Daosheng. Analysis of integral transform of the wave-induced response in seabed and its application[J]. Chinese Journal of Geotechnical Engineering,2006,28(7):847-852.(in Chinese)
[10] Wang Y K,Gao Y,Guo L,et al. Cyclic response of natural soft marine clay under principal stress rotation as induced by wave loads[J]. Ocean Engineering,2017,129:191-202.
[11] Anderson K H. Bearing capacity under cyclic loading-offshore,along the coast,and on land[J]. Canadian Geotechnical Journal,2009,46(5):513-535.
[12] Xia K,Wang J. Shear principal,and equivalent strains in equal-channel angular deformation[J]. Metallurgical and Materials Transactions A,2002,33(2):467-467.
[13] Casagrande A. Liquefaction and cyclic deformation of sands:a critical review[C]//Proceedings of the 5th Pan-American Conference on Soil Mechanics and Foundation Engineering. Buenos Aires,Argentian,1975.