Study on seabed response and liquefaction induced by waves in the southern tidal flat of Nanhui, Shanghai
-
摘要:
海床液化是海洋地质灾害中的一种常见现象，不仅会造成海床侵蚀，还会对区内海底管线、海洋设施等产生重大危害。目前，对海床液化机制研究大多基于室内物理模型实验，基于现场观测的研究较欠缺。本研究在南汇南滩进行了为期1个月的现场观测，利用固定平台的声学多普勒流速仪获得流速和水压等高频数据，并使用自制的孔隙水压力探杆获取海床土体不同深度的孔隙水压力数据。同时，分析了一次冬季大风事件期间孔隙水压力对波浪荷载的响应特征，计算了海床液化的深度。结果表明，孔隙水压力响应特征受潮位和波高的影响。总孔隙水压力响应的趋势受潮位影响，波致孔隙水压力响应的振幅受有效波高影响；研究区海床液化程度随深度的增加而降低，由于观测期间有效波高较低，液化深度仅为十几厘米。
Abstract:Seabed liquefaction is a common phenomenon in marine geological disasters, which not only leads to seabed erosion but also poses significant risks to subsea pipelines, marine facilities, and other structures in the area. At present, available studies on the mechanisms of seabed liquefaction is based mainly on indoor physical model experiments, and the field observations are very scarce. In this study, we conducted a one-month field observation at the southern tidal flat of Nanhui, Shanghai. An acoustic Doppler velocimeter was mounted at the fixed platform to obtain high-frequency data of flow velocity and water pressure. A self-made pore pressure probe was applied to collect pore pressure data at different depths of the seabed sediments. In addition, we analyzed the response characteristics of pore pressure to wave loading during a winter gale event and calculated the depth of seabed liquefaction. Results show that the characteristics of pore pressure response are affected by tidal level and wave height, of which the trend of total pore pressure response is affected by tidal levels, and the amplitude of wave-induced pore pressure response is affected by significant wave height. The degree of seabed liquefaction in the study area decreased with depth increase. Due to the relatively low significant wave height during the observation period, the liquefaction depth was only a dozen centimeters.
-
Key words:
- seabed liquefaction /
- pore pressure /
- effective stress /
- the southern tidal flat of Nanhui /
- lag effect
-
-
表 1 土力学参数
Table 1. Parameters of soil mechanics
参数 平均粒径/μm 密度/（g/cm3） 比重/（g/cm3） 含水率/% 孔隙率/% 范围 24.32～132.46 1.59～2.28 1.93～2.79 21～33 14～27 平均值 77.29 2.14 2.57 26 18 
下载: 导出CSV
表 2 2个潮周期海床浮容重、最大超孔压、最大超孔压发生时间、液化深度
Table 2. Seabed floating volume weight, maximum excess pore pressure, occurrence time of maximum excess pore pressure, and liquefaction depth in two tidal cycles
潮周期 浮容重/（kN/m3） Pmax/kPa Pmax发生时刻 液化深度/cm T1 10.72 1.19 03:56 16.7 T2 10.72 0.90 15:19 12.6
下载: 导出CSV
-
[1] MICHALLET H,MORY M,PIEDRA-CUEVA I. Wave-induced pore pressure measurements near a coastal structure[J]. Journal of Geophysical Research:Oceans,2009,114(C6).
[2] FREDSOE J,SUMER B M. The Mechanics of Scour in the Marine Environment[M]. Singapore:World Scientific Publishing Company,2002.
[3] JIA Y G,LIU X L,ZHANG S T,et al. Wave-forced Sediment Erosion and Resuspension in the Yellow River Delta[M]. Singapore:Springer,2020.
[4] SONG Y P,SUN Y F,WANG Z H,et al. In situ observation of silt seabed pore pressure response to waves in the subaqueous Yellow River Delta[J]. Journal of Ocean University of China,2022,21(5):1154-1160. doi: 10.1007/s11802-022-4843-3
[5] 王栋,栾茂田,郭莹. 波浪作用下海床动力反应有限元数值模拟与液化分析[J]. 大连理工大学学报,2001,41(2):216-222. doi: 10.3321/j.issn:1000-8608.2001.02.020
WANG D,LUAN M T,GUO Y. FEM-based numerical simulation of dynamic response and liquefaction analysis of seabed under wave-induced loading[J]. Journal of Dalian University of Technology,2001,41(2):216-222. doi: 10.3321/j.issn:1000-8608.2001.02.020
[6] ZEN K,YAMAZAKI H. Mechanism of wave-induced liquefaction and densification in seabed[J]. Soils and Foundations,1990,30(4):90-104. doi: 10.3208/sandf1972.30.4_90
[7] TZANG S Y,OU S H. Laboratory flume studies on monochromatic wave-fine sandy bed interactions:Part 1. soil fluidization[J]. Coastal Engineering,2006,53(11):965-982. doi: 10.1016/j.coastaleng.2006.06.003
[8] SASSA S,SEKIGUCHI H. Wave-induced liquefaction of beds of sand in a centrifuge[J]. Geotechnique,1999,49(5):621-638. doi: 10.1680/geot.1999.49.5.621
[9] MIYAMOTO J,SASSA S,SEKIGUCHI H. Progressive solidification of a liquefied sand layer during continued wave loading[J]. Geotechnique,2004,54(10):617-629. doi: 10.1680/geot.2004.54.10.617
[10] LUAN M T,ZHANG C,WANG D. Numerical analysis of residual pore water pressure development and evaluation of liquefaction potential of seabed under wave loading[J]. Journal of Hydraulic Engineering,2004,35(2):94-100.
[11] KIRCA V S O,SUMER B M,FREDSØE J. Residual liquefaction of seabed under standing waves[J]. Journal of Waterway,Port,Coastal,and Ocean Engineering,2013,139(6):489-501.
[12] MORY M,MICHALLET H,BONJEAN D,et al. A field study of momentary liquefaction caused by waves around a coastal structure[J]. Journal of Waterway,Port,Coastal,and Ocean Engineering,2007,133(1):28-38.
[13] ZEN K,YAMAZAKI H. Field observation and analysis of wave-induced liquefaction in seabed[J]. Soils and Foundations,1991,31(4):161-179. doi: 10.3208/sandf1972.31.4_161
[14] YEH H,MASON H B. Sediment response to tsunami loading:mechanisms and estimates[J]. Géotechnique,2014,64(2):131-143.
[15] HOLTZ R D,KOVACS W D,SHEAHAN T C. An Introduction to Geotechnical Engineering[M]. Englewood Cliffs,NJ:Prentice-hall,1981.
[16] SAKAI T,HATANAKA K,MASE H. Wave-induced effective stress in seabed and its momentary liquefaction[J]. Journal of Waterway,Port,Coastal,and Ocean Engineering,1992,118(2):202-206.
[17] 王刚,许国辉,刘志钦,等. 波致粉质土液化过程中物理力学性态变化试验研究[J]. 海洋地质与第四纪地质,2017,37(1):176-183.
WANG G,XU G H,LIU Z Q,et al. Experimental study on the physical and mechanical characteristics changes of wave induced liquefied silt[J]. Marine Geology & Quaternary Geology,2017,37(1):176-183.
[18] SASSA S,TAKAYAMA T,MIZUTANI M,et al. Field observations of the build-up and dissipation of residual pore water pressures in seabed sands under the passage of storm waves[J]. Journal of Coastal Research,2006:410-414.
[19] KIRCA V S O,SUMER B M,FREDSØE J. Influence of clay content on wave-induced liquefaction[J]. Journal of Waterway,Port,Coastal,and Ocean Engineering,2014,140(6):04014024.
[20] 许国辉,刘会欣,刘锦昆,等. 黏粒含量对粉质土液化发生的作用机制[J]. 海洋地质与第四纪地质,2012,32(3):31-35.
XU G H,LIU H X,LIU J K,et al. Role of clay content in silty soil liquefaction[J]. Marine Geology & Quaternary Geology,2012,32(3):31-35.
[21] DUAN L,JENG D S,WANG S,et al. Numerical investigation of the wave/current–induced responses of transient soil around a square mono-pile foundation[J]. Journal of Coastal Research,2019,35(3):625-636. doi: 10.2112/JCOASTRES-D-18-00072.1
[22] 许国辉,孙永福,于月倩,等. 黄河水下三角洲浅表土体的风暴液化问题[J]. 海洋地质与第四纪地质,2011,31(2):37-42.
XU G H,SUN Y F,YU Y Q,et al. Storm induced liquefaction of the surficial sediments in the Yellow River subaqueous delta[J]. Marine Geology & Quaternary Geology,2011,31(2):37-42.
[23] 刘晓磊,张淑玉,郑杰文,等. 黄河三角洲极端风暴诱发地质灾害研究进展及对策[J]. 海洋地质前沿,2022,38(11):28-39.
LIU X L,ZHANG S Y,ZHENG J W,et al. Research progress and countermeasures on geological hazards induced by extreme storms in the Yellow River[J]. Marine Geology Frontiers,2022,38(11):28-39.
[24] 常方强,贾永刚. 黄河水下三角洲液化引起的灾害研究现状[J]. 海洋地质与第四纪地质,2010,30(5):145-151.
CHANG F Q,JIA Y G. Review of the studies on geo-hazards induced by liquefaction at the Yellow River subaqueous delta[J]. Marine Geology & Quaternary Geology,2010,30(5):145-151.
[25] 王颖,朱大奎. 中国的潮滩[J]. 第四纪研究,1990(4):291-300. doi: 10.3321/j.issn:1001-7410.1990.04.001
WANG Y,ZHU D K. Tidal flats of China[J]. Quaternary Sciences,1990(4):291-300. doi: 10.3321/j.issn:1001-7410.1990.04.001
[26] 李九发,戴志军,刘新成,等. 长江河口南汇嘴潮滩圈围工程前后水沙运动和冲淤演变研究[J]. 泥沙研究,2010(3):31-37.
LI J F,DAI Z J,LIU X C,et al. Research on the movement of water and suspend sediment and sedimentation in Nanhui spit of the Yangtze Estuary before and after the construction of reclamation projects on the tidal flat[J]. Journal of Sediment Research,2010(3):31-37.
[27] 夏海峰,张玮. 南汇东滩及浦东国际机场外沿围海造地工程潮流数学模型研究[J]. 水道港口,2008,29(1):25-30. doi: 10.3969/j.issn.1005-8443.2008.01.005
XIA H F,ZHANG W. Tidal current simulation model for shoal reclamation at eastern tidal flat of Nanhui and east side of Pudong International Airport[J]. Journal of Waterway and Harbor,2008,29(1):25-30. doi: 10.3969/j.issn.1005-8443.2008.01.005
[28] 左书华,李蓓,杨华. 南汇嘴边滩地形演变及其分析[J]. 水道港口,2007(2):108-112. doi: 10.3969/j.issn.1005-8443.2007.02.007
ZUO S H,LI B,YANG H. Topography evolution and analysis of Nanhui nearshore[J]. Journal of Waterway and Harbor,2007(2):108-112. doi: 10.3969/j.issn.1005-8443.2007.02.007
[29] 赵建春,李九发,李占海,等. 长江口南汇嘴潮滩短期冲淤演变及其动力机制研究[J]. 海洋学报(中文版),2009,31(4):103-111.
ZHAO J C,LI J F,LI Z H,et al. Researches on characteristics and dynamic mechanism of short-term scouring and silting changes of the tidal flat on Nanhui Spit in the Changjiang Estuary in China[J]. Acta Oceanologica Sinica,2009,31(4):103-111.
[30] 左书华,时连强. 南汇嘴潮滩沉积物粒度特征研究[J]. 水道港口,2008(2):88-93. doi: 10.3969/j.issn.1005-8443.2008.02.003
ZUO S H,SHI L Q. Hydrodynamic explanation and characteristic of sediment granularity of Nanhuizui foreland in Changjiang Estuary[J]. Journal of Waterway and Harbor,2008(2):88-93. doi: 10.3969/j.issn.1005-8443.2008.02.003
[31] WANG T,LIU G P,GAO L,et al. Biological and nutrient responses to a typhoon in the Yangtze Estuary and the adjacent sea[J]. Journal of Coastal Research,2016,32(2):323-332.
[32] MENG L P,TU J B,WU X D,et al. Wave,flow,and suspended sediment dynamics under strong winds on a tidal beach[J]. Estuarine,Coastal and Shelf Science,2024,303:108799. doi: 10.1016/j.ecss.2024.108799
[33] 戴志军,陈建勇,路海亭. 长江河口南汇东滩与南滩沉积物空间相关特征分析[J]. 海洋湖沼通报,2008(2):46-52. doi: 10.3969/j.issn.1003-6482.2008.02.007
DAI Z J,CHEN J Y,LU H T. Analysis on the spatial distribution of deposition fields between the east bank and the south bank,in the Yangtze River Estuary[J]. Transactions of Oceanology and Limnology,2008(2):46-52. doi: 10.3969/j.issn.1003-6482.2008.02.007
[34] GORDON L,LOHRMANN A. Near-shore Doppler Current Meter Wave Spectra[M]. Virginia:Ocean Wave Measurement and Analysis,2002:33-43.
[35] XU X B,XU G H,YANG J J,et al. Field observation of the wave-induced pore pressure response in a silty soil seabed[J]. Geo-Marine Letters,2021,41:1-12. doi: 10.1007/s00367-020-00681-5
[36] QI W G,GAO F P. Wave induced instantaneously-liquefied soil depth in a non-cohesive seabed[J]. Ocean Engineering,2018,153:412-423. doi: 10.1016/j.oceaneng.2018.01.107
[37] 刘晓磊,贾永刚,郑杰文. 波浪导致黄河口海床沉积物超孔压响应现场试验研究[J]. 岩土力学,2015,36(11):3055-3062.
LIU X L,JIA Y G,ZHENG J W. In situ experiment of wave-induced excess pore pressure in the seabed sediment in Yellow River Estuary[J]. Rock and Soil Mechanics,2015,36(11):3055-3062.
-
图(8)
表(2)
计量
- 文章访问数: 41
- PDF下载数: 6
- 施引文献: 0