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A Study on the Design Method of Flexible Curtain Structures Moored under Storm Wave and Current

风暴潮和海流作用下系泊柔性幕墙结构设计方法研究

基本信息

批准号：
09555159
负责人：
MAENO Yoshihiko
金额：
$ 7.36万
依托单位：
NIHON UNIVERSITY JUNIOR COLLEGE
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09555159/
关键词：
Silt Curtain Field Observation Current Wave Measurement Tension Holding Power Floating Structure

项目摘要

The field verification on the holding power of mooring anchors was conducted on the seabed composed of silt and sand in Maizuru Bay and Tokyo Bay. We employed the concrete block anchor and the suction anchor.When the tensile forces acting on the mooring wires were measured, the pressure distributions were also measured at the bottom of the concrete block anchors and inside the suction anchor by varying the drawing angles of the anchor line or the drawing speed. Also, the field measurements on the behavior of silt curtain were conducted under stormy waves and currents. The field measurements were successfully completed and supplied the data required to estimate the drag coefficient of flared curtain structures. From the observation and analysis of I.he measured data during this period the followings are obtained.1. The holding power shows the maximum value at the drawing angle of 90 degree, and decreases with the drawing angle. But this tendency is not remarkable at the drawing angle le … More ss than 45 degree.2. The concrete block anchor shows a sharp peak of the holding power when the drawing speed is large. When the drawing speed is small the pressure distributes unevenly along the bottom plane. The suction anchor always shows a peak of the holding power independently of the drawing speed. It was also confirmed that the negative pressure inside the suction anchor changes in proportion to the holding power.2. The other data of tension shows the linear correlation between the static tension on mooring wire and the current velocity, up to a certain current velocity.3. The drag coefficient for current is also large as same as that for wave while the current velocity is low, and gradually approaches to 1. 0 as the velocity increases. The drag coefficient for wave is considerable large while Reynolds number/the velocity of water particle is low, and gradually approaches to 1. 0 as the velocity of water particle increases.5. Each of the drag coefficients for both stormy wave and current was predicted to be 1. 0. Since the large velocities of wave and current are induced at the same time by storm, the estimated drag coefficient of 1. 0 is reasonable to use for designing the flexible curtain structures under the wave and current. Less

在舞鹤湾和东京湾的淤泥和沙子组成的海床上对系泊锚的抓力进行了现场验证。采用混凝土块锚和吸力锚，在测量锚绳拉力的同时，通过改变锚绳的拉绳角度和拉绳速度，测量了混凝土块锚底部和吸力锚内部的压力分布。同时，对风浪和海流作用下的挡沙帷幕进行了现场实测。成功地完成了现场测量，并提供了估算喇叭形幕墙结构阻力系数所需的数据。通过对这一时期的实测资料的观察和分析，得出以下结论：1.拉深角为90 °时，保持力最大，随着拉深角的增大，保持力逐渐减小。但在拉深角度le时，这种趋势并不显著 ...更多信息 ss大于45度。当拉拔速度较大时，混凝土块锚的抓持力出现一个尖峰。当拉拔速度较小时，压力沿底面沿着分布不均匀。吸力锚总是显示出与拉伸速度无关的保持力的峰值。还证实了吸力锚内的负压与保持力成比例地变化。张力数据显示，在一定的流速范围内，系泊缆上的静张力与流速呈线性关系.流速较低时，水流的阻力系数与波浪的阻力系数一样大，并逐渐接近1。0随着速度的增加。当雷诺数/水质点速度较小时，波浪阻力系数较大，并逐渐接近1。0随着水质点速度的增加.风浪和海流的阻力系数均为1。0.由于风暴同时产生了较大的波、流速度，因此计算的阻力系数1。在波流共同作用下，柔性帷幕结构的设计采用0是合理的。少