北部湾东侧莺东沙脊及其在管线工程中的负面作用  

YINGDONG SAND RIDGES IN EAST BEIBU GULF AND THEIR IMPACT ON PIPELINE ENGINEERING

作　　者：陈昌翔 曹立华[1] 庄振业[1] 徐继尚[1] 杨顺良 赵东波 CHEN Changxiang;CAO Lihua;ZHUANG Zhenye;XU Jishang;YANG Shunliang;ZHAO Dongbo(College of Marine Geosciences, Ocean University of China, Qingdao 266100, China;Ocean Research Institution,Fujian Province,Xiamen 361013,China;Fujian Provincial Key Laboratory of Coast and Island Management Technology Study,Xiamen 361013,China)

机构地区：[1]中国海洋大学海洋地球科学学院,青岛266100 [2]福建省海洋研究所,厦门361013 [3]福建省海岛与海岸带管理技术研究重点实验室,厦门361013

出　　处：《海洋地质前沿》2018年第4期49-55,共7页Marine Geology Frontiers

基　　金：国家海洋局公益性项目"海岛旅游海滩管理技术研究与应用示范"(201405037);福建省海岛与海岸带管理技术研究重点实验室项目(CIMTS-2016-01)

摘　　要：北部湾东侧莺东潮流沙脊是整个琼西南沙脊群之一,沙脊从感恩角岸外发育最好,至东方岸外已趋缓和。根据海底特征,由海向岸分为深水平坦段、沙波沙脊段和近岸段共3个区段。沙波沙脊区段主要分布4条沙脊,这些沙脊大都呈NS或NW—SE走向,与主水流平行,呈不甚规则的长条状,长约45km,宽度较大。脊槽高差约20~30m,脊顶水深5~8m,沙脊槽向不对称,向海侧缓,向陆侧陡。成因上属于全新世低海面形成的连滨沙脊,受现代浪流修蚀改造而成。这些沙脊的基础部分基本稳定,只在暴风浪或强潮流情况下表面活动性泥沙做少量迁移。2003年铺设的东方1-1气田输气管线路由经过北部湾莺东沙脊。通过对中国海洋大学东方1-1海底管线多年调查资料分析认为,本区沙波沙脊海底管线被严重掏空,已发现的130余掏空悬跨点平均长达33m,深度最大可达1m。管线掏空可归因于底形特征动态变化和管线改变海底水动力环境的综合作用。The Yingdong tidal sand ridge, which occurs in the east of Beibu gulf, is a part of the Qion- gxinan sand ridge system. It is well developed outside the Ganen Cornor and smmothly extends to Dongfang. The sand ridge area can be divided into three sections,the deep water flat section,the cur- rent ridge and sand wave section and the nearshore section, from the offshore to the coast. In the cur- rent ridge and sand wave section, there are four sand ridges in NS or NW-SE direction roughly parallel to the main flow. The ridges are about 45km long with a large width. The valleys between ridges are usually 20-30m in depth, while the ridge top is 5-8m below sea level. Sand valleys are asymmetrical, steep on the land side and gentle on the sea side. The sand ridges were formed in the period of low sea level in Holocene and then eroded by modern wave. The foundation of sand ridge is strong and firm. Only in case of storm wave or strong current, can the surface sediment move in a small distance. In 2008, the Dongfang 1-1 seafloor pipeline was constructed, which passed through the Yingdong tidal sand ridge. Through the analysis of the Dongfang 1-1 offshore pipeline survey data acquired by OUC after construction, it is found that there are 130 points where the pipeline are suspended. The suspen- ded part is 33m long on average and the distance between the pipe and the sea bottom is lm in maxi- mum. The suspension of pipeline is caused by the changes in bedforms and/or water dynamics.

关 键 词：北部湾 潮流沙脊 东方1-1海底管线 管线掏空 

分 类 号：P75[天文地球—海洋科学]