TRANSFORMATION OF GRANULAR COMPOSITION AND MICROSTRUCTURE OF SILT DUE TO CYCLIC LOADING IN YELLOW RIVER ESTUARY,CHINA
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摘要: 在黄河三角洲潮坪采集循环振动荷载施加前后长1 m的原状样各一个,在实验室对原状样以10 cm为间隔取样,进行粒度成分分析和微结构观测,研究循环振动荷载导致的海床土成分与结构的变化。发现总体上振动导致土体颗粒长轴呈现竖向排列趋势,深0~40 cm的表层土细粒含量增高,级配变好;深40~70 cm土体细粒含量降低,级配变差;70 cm以下土体受振动影响不明显。现场海床土孔隙水压力监测结果表明,这种海床土的成分结构变异与循环荷载导致土体重复液化及渗流场作用有关。Abstract: From the tidal flat of the Yellow River Estuary,each undisturbed sample of 1 m long was collected before and after cyclic vibrating. The microstructure has been observed with SEM and the transformation characteristics of the granularity have been contrasted at an interval of 10 cm.The results revealed that granularity direction strengthened and the long axes are in a perpendicular trend in general;fine grains gathered in certain areas above 40 cm depth,so the asymmetry coefficient rised and the gradation became better.The granularity change of soil from 40 to 70 cm depth was quite on the contrary;changes below 70 cm depth were not so obvious.The reason may be due to repeat liquefaction of seabed and the variations of seepage field that were induced by cyclic vibration.
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Keywords:
- silt /
- cyclic loading /
- granularity composition /
- microstructure /
- Yellow River Estuary
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[1] Madsen O S.Wave-induced pore pressure and effective stresses in a porous bed[J].Geotechnique,1978,28(4):377-393.
[2] Hsu J R C.Wave induced soil response in an unsaturated anisotropic seabed of finite thickness[C]//International Journal of Numerical and Analytical Methods in Geomechanics.1995,19:825-849.
[3] Goddard J D.Nonlinear elasticity and pressure dependent wave speeds in granular media[C]//Proc.R.Soc.Lond.,1990(A),430:105-131.
[4] Bennett R H.In situ porosity and permeability of selected carbonate sediment:Great Bahamal:Measurements[J].Marine Geotechnology,1990(9):1-28.
[5] YANG Shao-li,SHEN Wei-quan,YANG Zuo-sheng.The mechanism analysis of seafloor silt liquefaction under waveloading[J].China Ocean Engineering,1999,9(4):375-386.
[6] 单红仙,刘媛媛,贾永刚.动力作用下黄河水下三角洲粉质土微结构改造研究[J].岩土工程学报,2003,26(5):654-658. [SHAN Hong-xian,LIU Yuan-yuan,JIA Yong-gang.Case study of microstructure transform of silt due to wave action on subaqueous slope of Yellow River,China[J].Chinese Journal of Geotechnical Engineering,2003,26(5):654-658.]
[7] David H Shull,Michie Yasuda.Size-selective downward particle transport by cirratulid polychaetes[J].Journal of Marine Research,2001(59):453-473.
[8] 贾永刚,周其健.生物活动对海床沉积物工程地质特征改造研究[J].工程地质学报2005,13(1):49-56. [JIA Yong-gang,ZHOU Qi-jian Biological effects on engineering geological properties of seabed sediments[J].Journal of Engineering Geology,2005,13(1):49-56.]
[9] 贾永刚,霍素霞,许国辉,等.黄河水下三角洲沉积物强度变化原位测试研究[J].岩土力学,2004,25(6):876-881. [JIA Yong-gang,HUO Su-xia,XU Guo-hui,et al.Intensity variation of sediments due to wave loading on subaqueous delta of Yellow River[J].Rock and Soil Mechanics,2004,25(6):876-881.]
[10] 施斌.粘性土击实过程中微观结构的定量评价[J].岩土工程学报,1996,18(4):57-62. [SHI Bin.Quantitative assessment of changes of microstructure for clayey soil in the process of compaction[J].Chinese Journal of Geotechnical Engineering,1996,18(4):57-62.]
[11] 雷华阳.饱和软黏土固结变形的微结构效应[J].水利学报,2004(4):91-95.[LEI Hua-yang.Microstructural effect of consolidation deformation in saturated soft clay[J].Shui Li Xue Bao,2004 (4):91-95.]
[12] 胡瑞林,李卓芬.动荷载作用下黄土的强度特征及结构变化机理研究[J].岩土工程学报,2000,22(2):174-181. [HU Rui-lin,LI Zhuo-fen.Approach to the strength behaviors and microstructural changes of loess under dynamic load[J].Chinese Journal of Geotechnical Engineering,2000,22(2):174-181.]
[13] 刘忠玉.无粘性土中管涌的临界水头梯度研究[J].郑州大学学报,2003,24(4):67-71. [LIU Zhong-yu. Critical hydraulic gradient for piping in noncohesive soils[J].Journal of Zheng-zhou University(Engineering Science),2003,24(4):67-71.]
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