部分排水时饱和粉质黏土变围压循环三轴试验研究
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摘要
围压循环变化将引起土体孔压累积,加剧土体累积塑性应变,导致地基灾变事故。为研究围压循环变化对饱和粉质黏土变形特性的影响,利用GDS双向振动三轴仪,进行部分排水时饱和粉质黏土的变围压循环三轴试验,研究不同应力路径斜率和循环动应力比时饱和粉质黏土的孔压、轴向累积塑性应变和体应变发展规律,建立部分排水条件时考虑循环围压和循环动应力耦合作用的地基粉质黏土累积应变数学模型。试验结果表明:部分排水时饱和粉质黏土孔压、轴向累积塑性应变和体应变均随循环动应力比和应力路径斜率的增大而增大;动孔压比随着振动次数的增加明显分为急剧增加、快速下降和持续平稳3个阶段;轴向累积塑性应变和体应变均随振动次数的增加而增大。当加载次数超过2 500次时,粉质黏土孔压趋于平稳,变形速率略有降低,但变形持续增加。补充试验结果表明,所建立模型与试验结果具有较高的一致性。研究结果将为交通循环荷载导致的地基灾变控制技术提供理论依据。
The varying cyclic confined pressures will aggravate the pore water pressure and the accumulated plastic strain of soil and even lead to the catastrophic accident. The triaxial tests with cyclic confining pressure were carried out to study the pore pressure, the axial cumulative plastic strain and the volumetric strain of saturated silty clay under different stress paths and cyclic dynamic stress ratios by using GDS triaxial apparatus under partial drained conditions. A mathematical model of accumulated strain for silty clay under cyclic confining pressure and cyclic dynamic stress was established under partial drainage conditions. The experimental results show that the pore water pressure, axial cumulative plastic strain and volumetric strain of the saturated silty clay increase as the cyclic dynamic stress ratio and the stress path slope increases. The dynamic pore pressure ratio versus vibration number curves divided into three stages: rapid increase stage, rapid decline stage and sustained stability stage, respectively. The axial cumulative plastic strain and volumetric strain increase as the vibration number increases. The pore pressure of silty clay tends to be stable, while the deformation rate decreases slightly, but the deformation increases continuously when the number of loading is more than 2 500 times. The supplementary experimental results show that the established model is in good agreement with the experimental results. The results will provide a theoretical basis for the foundation disaster control technology caused by traffic cycle load.
The varying cyclic confined pressures will aggravate the pore water pressure and the accumulated plastic strain of soil and even lead to the catastrophic accident. The triaxial tests with cyclic confining pressure were carried out to study the pore pressure, the axial cumulative plastic strain and the volumetric strain of saturated silty clay under different stress paths and cyclic dynamic stress ratios by using GDS triaxial apparatus under partial drained conditions. A mathematical model of accumulated strain for silty clay under cyclic confining pressure and cyclic dynamic stress was established under partial drainage conditions. The experimental results show that the pore water pressure, axial cumulative plastic strain and volumetric strain of the saturated silty clay increase as the cyclic dynamic stress ratio and the stress path slope increases. The dynamic pore pressure ratio versus vibration number curves divided into three stages: rapid increase stage, rapid decline stage and sustained stability stage, respectively. The axial cumulative plastic strain and volumetric strain increase as the vibration number increases. The pore pressure of silty clay tends to be stable, while the deformation rate decreases slightly, but the deformation increases continuously when the number of loading is more than 2 500 times. The supplementary experimental results show that the established model is in good agreement with the experimental results. The results will provide a theoretical basis for the foundation disaster control technology caused by traffic cycle load.
引文
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[2]刘家顺,张向东,孙家宝,等.主应力轴旋转下K0固结饱和粉质黏土孔压及变形特性试验研究[J].岩土力学,2018,39(8):2787-2804.LIU Jia-shun,ZHANG Xiang-dong,SUN Jia-bao,et al.Experimental research on the pore pressure and deformation characteristics of K0 consolidated saturated silty clay under the principal stress axis rotation[J].Rock and Soil Mechanics,2018,39(8):2787-2804.
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[4]NOORZAD R,SHAKERI M.Effect of silt on post-cyclic shear strength of sand[J].Soil Dynamics and Earthquake Engineering,2017(97):133-142.
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[11]ASAOKA A,NAKANO M,MATSUO M.Prediction of the partially drained behavior of soft clays under embankment loading[J].Soils and Foundations,1992,32(1):41-58.
[12]SEKIGUCHI H,NISHIDA Y,KANAI F.Analysis of partially-drained triaxial testing of clay[J].Soils and Foundations,1981,21(3):53-66.
[13]SAKAI A,SAMANG L,MIURA N.Partially-drained cyclic behavior and its application to the settlement of a low embankment road on silty-clay[J].Soils and Foundations,2003,43(1):33-46.
[14]YAGHTIN M S,LASHKARI A.Modeling sand behavior under partially drained stress paths[C]//Bifurcation and Degradation of Geo-materials with Engineering Applications.Springer Series in Geomechanics and Geoengineering.[S.l.]:Springer,2017:97-103.
[15]周星辰.部分排水条件下饱和黏土的强度试验研究[J].科学技术与工程,2017,17(20):223-229.ZHOU Xing-chen.Experimental study on saturated clay strength under partial drainage conditions[J].Science Technology and Engineering,2017,17(20):223-229.
[16]吴建奇,杨骁,徐旭,等.部分排水条件下饱和红黏土循环试验研究[J].浙江大学学报(工学版),2017,51(7):1309-1317.WU Jian-qi,YANG Xiao,XU Xu,et al.Cyclic triaxial tests on saturated red clay under partially drained condition[J].Journal of Zhejiang University(Engineering Science),2017,51(7):1309-1317.
[17]南京水利科学研究院.SL 237-1999.土工试验规程[S].北京:中国水力水电出版社,1999.Nanjing Hydraulic Research Institute.SL 237-1999.Specification of soil test[S].Beijing:China Water&Power Press,1999.
[18]刘家顺.高速铁路粉质黏土地基静、动力特性及沉降规律研究[D].阜新:辽宁工程技术大学,2015:90-100.LIU Jia-shun.Research on the static and dynamic characteristics of silty clay and the settlement law of subgrade of high-speed railway[D].Fuxin:Liaoning Technical University,2015:90-100.
[2]刘家顺,张向东,孙家宝,等.主应力轴旋转下K0固结饱和粉质黏土孔压及变形特性试验研究[J].岩土力学,2018,39(8):2787-2804.LIU Jia-shun,ZHANG Xiang-dong,SUN Jia-bao,et al.Experimental research on the pore pressure and deformation characteristics of K0 consolidated saturated silty clay under the principal stress axis rotation[J].Rock and Soil Mechanics,2018,39(8):2787-2804.
[3]谷川.基于变围压应力路径对的饱和软黏土动力特性试验研究[D].杭州:浙江大学,2013:52-69.GU Chuan.Study on the dynamic behavior of saturated clays based on the stress paths with variable confining pressure[D].Hangzhou:Zhejiang University,2013:52-69.
[4]NOORZAD R,SHAKERI M.Effect of silt on post-cyclic shear strength of sand[J].Soil Dynamics and Earthquake Engineering,2017(97):133-142.
[5]SUN BI,ZHU ZHENDE,SHI CHONG,et al.Dynamic mechanical behavior and fatigue damage evolution of sandstone under cyclic loading[J].International Journal of Rock Mechanics&Mining Sciences,2017,94:82-89.
[6]施明雄.多向振动下砂土动力特性试验研究[D].杭州:浙江大学,2008:15-21.SHI Ming-xiong.Sand response to multi-way dynamic loading[D].Hangzhou:Zhejiang University,2008:15-21.
[7]GRABE P J.Effects of principal stress rotation on permanent deformation in rail track foundations[J].Journal of Geotechnical and Geoenvironmental Engineering,2009,135(4):555-565.
[8]孙磊,王军,谷川,等.循环偏应力和循环围压耦合效应对饱和软黏土变形特性的影响[J].岩土工程学报,2015,37(12):2198-2204.SUN Lei,WANG Jun,GU Chuan,et al.Coupling effects of cyclic deviator stress and cyclic confining pressure on deformation behavior of saturated clay[J].Chinese Journal of Geotechnical Engineering,2015,37(12):2198-2204.
[9]孙磊,蔡袁强,王军,等.循环围压对饱和软黏土永久变形的影响[J].岩土力学,2015,36(2):437-442.SUN Lei,CAI Yuan-qiang,WANG Jun,et al.Effects of cyclic confining pressure on permanent deformation of saturated soft clay[J].Rock and Soil Mechanics,2015,36(2):437-442.
[10]郭林,蔡袁强,谷川,等.循环荷载下软黏土回弹和累积变形特性[J].浙江大学学报(工学版),2013,47(12):2111-2117.GUO Lin,CAI Yuan-qiang,GU Chuan,et al.Resilient and permanent strain behavior of soft clay under cyclic loading[J].Journal of Zhejiang University(Engineering Science),2013,47(12):2111-2117.
[11]ASAOKA A,NAKANO M,MATSUO M.Prediction of the partially drained behavior of soft clays under embankment loading[J].Soils and Foundations,1992,32(1):41-58.
[12]SEKIGUCHI H,NISHIDA Y,KANAI F.Analysis of partially-drained triaxial testing of clay[J].Soils and Foundations,1981,21(3):53-66.
[13]SAKAI A,SAMANG L,MIURA N.Partially-drained cyclic behavior and its application to the settlement of a low embankment road on silty-clay[J].Soils and Foundations,2003,43(1):33-46.
[14]YAGHTIN M S,LASHKARI A.Modeling sand behavior under partially drained stress paths[C]//Bifurcation and Degradation of Geo-materials with Engineering Applications.Springer Series in Geomechanics and Geoengineering.[S.l.]:Springer,2017:97-103.
[15]周星辰.部分排水条件下饱和黏土的强度试验研究[J].科学技术与工程,2017,17(20):223-229.ZHOU Xing-chen.Experimental study on saturated clay strength under partial drainage conditions[J].Science Technology and Engineering,2017,17(20):223-229.
[16]吴建奇,杨骁,徐旭,等.部分排水条件下饱和红黏土循环试验研究[J].浙江大学学报(工学版),2017,51(7):1309-1317.WU Jian-qi,YANG Xiao,XU Xu,et al.Cyclic triaxial tests on saturated red clay under partially drained condition[J].Journal of Zhejiang University(Engineering Science),2017,51(7):1309-1317.
[17]南京水利科学研究院.SL 237-1999.土工试验规程[S].北京:中国水力水电出版社,1999.Nanjing Hydraulic Research Institute.SL 237-1999.Specification of soil test[S].Beijing:China Water&Power Press,1999.
[18]刘家顺.高速铁路粉质黏土地基静、动力特性及沉降规律研究[D].阜新:辽宁工程技术大学,2015:90-100.LIU Jia-shun.Research on the static and dynamic characteristics of silty clay and the settlement law of subgrade of high-speed railway[D].Fuxin:Liaoning Technical University,2015:90-100.
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