刘珊,刘浩晨

• 1:浙江同济科技职业学院
• 2:中铁二院华东勘察设计有限责任公司

摘要(Abstract)：

我国东南海域广泛分布黏土海床,针对单向流作用下黏土海床中单桩基础的局部冲刷问题,开展了5组不同水深和流速的室内水槽试验,并通过在模型桩内布设摄像头,实时监测捕捉桩周冲刷深度随时间的变化特征,分析黏土中单桩局部冲刷发展规律。结果表明:黏土冲刷的稳定时间与砂土冲刷相类似,冲刷坑的形状发展也较为相似,但是黏土海床冲刷坑的底部边界相对粗糙,这主要是由于黏土黏聚力所致;随着桩前入射流速的逐渐增加,桩周最大冲刷点的位置呈现出从桩侧向桩后发展的趋势;当水深和入射流速较大时,水流除了在桩周形成大范围的冲刷浅坑之外,还会在桩后1倍桩径(1D)处形成直径大约为1D的冲刷深坑;冲刷深坑的边界会延伸到单桩桩周,致使部分埋置桩身暴露,这很可能导致桩基承载力的降低。

关键词(KeyWords)： 黏土;单桩;单向流;图像分析;冲刷深度

Abstract:

Keywords:

基金项目(Foundation): 浙江省水利厅科技计划项目(RC2063);; 国家自然科学基金资助项目(51779220)

作者(Author): 刘珊,刘浩晨

DOI: 10.13928/j.cnki.wrahe.2022.01.010

参考文献(References)：

• [1] MELVILLE B W,SUTHERLAND A J.Design method for local scour at bridge piers[J].Journal of Hydraulic Engineering,1988,114(10):1210-1226.
• [2] BREUSERS H N C,NICOLLET G,SHEN H W.Local scour around cylindrical piers[J].Journal of Hydraulic Engineering,1977,15(3):211-252.
• [3] SHEN H W,SCHNEIDER V R,KARAKI S.Local scour around bridge piers[J].Journal of the Hydraulics Division,1969,95(6):1919-1940.
• [4] 马丽丽，国振，王立忠，等.单向流条件下单桩桩周冲刷过程特征试验研究[J].海洋工程，2017,35(1):136-146.MA L L,GUO Z,WANG L Z,et al.Scour charateristics at the periphery of a vertical pile under steady flow[J].The Ocean Engineering,2017,35(1):136-146.
• [5] MA L L,WANG L Z,GUO Z,et al.Time development of scour around pile groups in tidal currents[J].Ocean Engineering,2018,163:400-418.
• [6] GUO Z,JENG D S,ZHAO H Y,et al.Effect of seepage flow on sediment incipient motion around a free spanning pipeline[J].Coastal Engineering,2019,143:50-62.
• [7] GUO Z,ZHOU W J,ZHU C B,et al.Numerical simulations of wave-induced soil erosion in silty sand seabeds[J].Journal of Marine Science and Engineering,2019,7(2):52-71.
• [8] LI K,GUO Z,WANG L Z,et al.Effect of seepage flow on shields number around a fixed and sagging pipeline[J].Ocean Engineering,2019,172:487-500.
• [9] 沙玉清.泥沙运动学引论[M].北京：中国工业出版社，1965.SHA Yuqing.Introduction to kinematics of sediment[M].Beijing:China Industry Press,1965.
• [10] 窦国仁.论泥沙起动流速[J].水利学报，1960(4):44-60.DOU Guoren.On threshold velocity of sediment[J].Journal of Hydraulic Engineering,1960(4):44-60.
• [11] 唐存本.泥沙起动的规律[J].水利学报，1963(2):l-12.TANG Cunben.Law of sediment initiation[J].Journal of Hydraulic Engineering,1963(2):1-12.
• [12] DUNN J S.Thactive resistance of cohesive channels [J].Journal of soil Mechanics and Foundation Division,ASCE,1959,85:l-24.
• [13] 万兆惠，宋天成，何青.水压力对细颗粒泥沙起动流速影响的试验研究[J].泥沙研究，1990(4):62-69.WAN Zhaohui,SONG Tiancheng,HE Qing.Experimental study on the effect of water pressure on the threshold velocity of fine sediment[J].Journal of Sediment Research,1990(4):62-69.
• [14] 黄岁梁，陈稚聪，府仁寿.粘性类土的起动模式研究[J].水动力学研究与进展，1997,12(1):1-7.HUANG Suiliang,CHEN Zhicong,FU Renshou.Study on starting model of clay of all types[J].Journal of Hydrodynamics,1997,12(1):1-7.
• [15] 洪大林，缪国斌，邓东升，等.黏性土起动研究现状综述[J].水利水电科技进展，2005,25(6):102-106.HONG Dalin,MIAO Guodong,DENG Dongsheng,et al.Summarization of cohesive soil initiation[J].Advances in Science and Technology of Water Resources,2005,25(6):102-106.
• [16] 毛宁.论黏土起动机理[J].长江科学院院报，2010,27(9):53-58.MAO Ning.Erosion mechanism of clay[J].Journal of Yangtze River Scientific Research Institute,2010,27(9):53-58.
• [17] 孙宁松，孙永福，宋玉鹏.海洋平台桩基冲刷及影响因素分析[J].海岸工程，2004,23(4):38-44.SUN Ningsong,SUN Yongfu,SONG Yupeng.Scour around pile foundation of offshore platform and analysis of affecting factors[J].The Ocean Engineering,23(4):38-44.