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Disaster prevention work of coastal structure caused by vulnerated sand bed around coastal structure under attack of stormy wave

暴风浪袭击下海岸结构物周围沙床受损引起的海岸结构物防灾工作

基本信息

批准号：
11650529
负责人：
MAENO Shiro
金额：
$ 2.3万
依托单位：
OKAYAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

It is well known that a cyclic transient liquefaction of sea bed occurs under wave motion. In this study, the mechanism of a disaster caused by the dynamic behavior of wave-structure interaction such as a floatation of a buried submarine pipeline, a flow out of back-filling sand behind a revetment and so on is investigated experimentally and theoretically.1.A dynamic response of submarine pipeline buried in a sandy seabed under cyclic loading of water pressure is examined experimentally and theoretically. Characteristics of cyclic hydrodynamic forces acting on the buried pipeline is clarified by small scale laboratory tests, and a floatation process of the buried pipeline is also clarified by the method of discreet element analysis. A parametric study was carried out in order to investigate the influence of burial depth, specific weight of pipeline, permeability of sand bed, and frequency of pressure loading on the floatation of pipe. An analysis of the pipeline stability potential against floatation is presented, in which all the experimental test cases are verified.2.A dynamic behavior of sand bed around revetment under cyclic loading of water pressure is investigated experimentally and theoretically. Flow out of back-filling sand is confirmed experimentally. Validity of the high permeable sand and the length of the revetment to reduce the amount of flow out of back-filling sand is clarified.3.Flow out process of back-filling sand behind revetment is simulated by coupled analysis of distinct element method and finite element method. DEM-FEM analysis showed the flow out process of back-filling sand behind revetment under wave motion.

众所周知，在波浪作用下，海床会发生周期性的瞬态液化。本文对波浪与结构物相互作用引起的海底管道上浮、护岸后回填砂溢出等灾害的机理进行了实验和理论研究。1.对桑迪海床中的海底管道在水压循环荷载作用下的动力响应进行了实验和理论研究。通过室内小尺度试验，阐明了作用在埋地管道上的循环水动力特性，并采用离散元分析方法，阐明了埋地管道的上浮过程。为研究埋深、管道比重、砂层渗透率和压力加载频率对管道上浮的影响，进行了参数研究。对管道抗浮稳定性进行了分析，并对所有试验工况进行了验证。2.对水压力循环荷载作用下护岸周围砂床的动力特性进行了试验研究和理论分析。通过实验证实了回填砂的出砂。阐明了高透水性砂和护岸长度对减少回填砂流出量的有效性。3.采用离散元法和有限元法耦合分析，模拟了护岸后回填砂的流出过程。DEM-FEM分析揭示了波浪作用下护岸后回填砂的流出过程。