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

在舞津湾和东京湾的泥沙组成的海底进行了系泊锚杆持力的现场验证。我们采用了混凝土块锚和吸力锚。在测量作用在锚索上的拉力的同时，通过改变锚索的拉拔角度或拉拔速度，测量混凝土块锚底部和吸力锚内部的压力分布。同时，对淤泥幕在风浪和水流作用下的性能进行了实测。现场测量成功完成，并提供了估算喇叭形帷幕结构阻力系数所需的数据。通过对这段时间内实测数据的观察和分析，得出以下结论：握持力在拉伸角度为90度时达到最大值，随着拉伸角度的增大而减小。但在拉伸角大于45度时，这种倾向并不显著。当拉拔速度较大时，混凝土块锚的持力出现一个尖峰。当拉拔速度较小时，压力沿底平面分布不均匀。吸力锚的持力峰值与拉拔速度无关。还证实了吸力锚内负压随持力成比例变化。张力的其他数据表明，在一定的电流速度下，系泊索的静态张力与电流速度呈线性相关。当流速较低时，流的阻力系数也与波的阻力系数一样大，并逐渐趋近于1。当速度增加时为0。波浪阻力系数较大，而雷诺数/水粒子速度较低，并逐渐趋近于1。随着水粒子速度的增加，为0。预测风暴波和海流的阻力系数均为1。0. 由于风暴同时引起波浪和水流的大速度，因此估计阻力系数为1。在设计波浪和水流作用下的柔性幕结构时，使用0是合理的。少

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