Department of experimental system for soil-water-structure coupled models by using a drum centrifuge

本研究的主要目的是开发一个转鼓离心机波动现象模拟系统，使我们能够对土-水-结构系统的耦合现象进行物理模拟。设计了一个安装在现有直径为0.8m的转鼓离心机中的系统。通过适当的相似考虑，设计的波浪发生器的行程为15 mm，采用可变电机，频率为5.7Hz。系统上还安装了一台CCD摄像机，可以直观地跟踪离心力场下波浪的运动。实验证明，该系统在100 G离心加速度下工作正常。结果发现，桨的形状起着重要的作用，以确定所产生的波的特性和四个桨和测试，以找到最佳的形状。通过一系列生产性试验，研究了波浪作用下砂层的孔隙水压力响应，结果表明，波浪作用下砂层产生了高达1.2kPa的超静孔隙水压力，导致了砂层的液化现象。本研究所建立之试验系统可应用于波浪作用下，于桑迪层中或砂层上建造之结构物之稳定性研究。本研究的成果将发表在里约热内卢举行的”土力学和路面力学最新发展论文集“中的“微型离心机的发展和一些初步试验”和中国地区土力学和基础工程国内会议上。

The main target in this research is to develop a system for simulating a wave phenomenon in a drum centrifuge, which enables us to perform physical modeling of coupled phenomena of soil-water-structure systems. A system was designed to be housed in the existing drum centrifuge of 0.8m in diameter. By consideration of proper similitude, the designed wave generator has a capacity of 15mm stroke and 5.7Hz by a variable motor. A CCD camera was also mounted on the system to trace visually wave actions under centrifugal field. It was proved that the system successfully functions under as much as 100G centrifugal acceleration. It was found that the shape of paddle plays an important role to determine the characteristics of wave generated and four paddles were made and tested to find the best shape. A series of productive tests was carried out to see the responses of pore water pressure in a sand layr due to wave action, revealing that excess pore water pressure of as much as 1.2 kPa was generated, leading a liquefaction phenomenon. The test system established in this study could be applied to examine the stability of structure constructed in or on a sandy layr during wave actions. The outcomes of this research are to appear in two papers, one is "Development of minidrum centrifuges and a few initial tests" in the Proceeding of Recent Development of Soil Mechanics and Pavement Mechanics" to be held in Rio de Janeiro, the other is a domestic meeting of Chugoku Region on Soil Mechanics and Foundation Engineering.