Study on the dynamic failure mechanism of a gravity caisson quay wall due to earthquake forces

地震力作用下重力沉箱码头墙动力破坏机理研究

基本信息

批准号：
11555128
负责人：
MIMURA Mamoru
金额：
$ 7.36万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
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

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555128/
关键词：
centrifuge model test gravity caisson fault type earthquake liquefaction finite element analysis lateral displacement excess porewater pressure seismic behavior 過剩間隙水圧液状化抵抗原位置試験砂非排水繰返し三軸試験

项目摘要

A series of centrifuge tests was carried out to assess the seismic behavior of a gravity caisson quay wall with reclaimed backfill. The caisson model has been constructed with 3 water pressure cells and 3 earth pressure cells on the back of it to measure the water pressure as well as the earth pressure acting at the boundary between the caisson and the reclaimed backfill, that is thought to cause the seismic behavior of the gravity caisson due to earthquake force. Other pressure cells were installed in the reclaimed backfill and the replaced sand beneath the caisson to monitor the occurrence of liquefaction that may also become a main cause for the deformation of the gravity caisson quay wall. Effect of the physical properties of the frontal seabed, the shape of the gravity caisson and the frequency of the sinusoidal wave applied as a seismic force on the gravity caisson was mainly examined. The seismic force was applied to the backfilled caisson quay wall under 30G centrifugal conditi … More on.Liquefaction occurred in the reclaimed backfill whereas the partial liquefaction took place in the replaced sand beneath the caisson because of the increase in stress due to the existence of the gravity caisson. Due to the inertia force, decrease in the bearing capacity of the replaced sand and the dynamic pressure of the reclaimed backfill, the gravity caisson moved seaward with a frontal subsidence into the rubble mound. The measured lateral displacement of the caisson was about 40 cm in this particular case. Considering the scale effect, the derived displacement is found to be rational by comparing the achievement reported from the Hyogoken-Nambu Earthquake.Numerical analysis was also carried out using the code "LIQCA" to describe the performance of the centrifuge model tests. The parameters for the code have been rationally determined on the basis of the laboratory experiments on the same material used in the centrifuge model tests and the measured data by the centrifuge model tests. The derived accelerations both from the numerical analysis and the centrifuge model tests were filtered and compared. Both filtered accelerations showed a good match. Although the calculated displacement slightly overestimated the experimental one, the numerical results can precisely describe the experimental ones, particularly the process of generation/dissipation of the excess pore water pressure in the reclaimed backfill as well as the replaced sand beneath the caisson. From those results, the procedure with centrifuge model tests and the numerical assessment adopted in this research has been found to be useful to assess the in-situ performance of the gravity caisson quay wall with the reclaimed backfill quite well. Less

进行了一系列离心测试，以评估带有回收回填的重力Caisson码头壁的地震行为。 Caisson模型已经用3个水压细胞和其背面的3个地球压力细胞构建，以测量水压以及作用于Caisson和回收回填之间边界的地球压力，这被认为会导致地震行为，这是由于地震力引起的。其他压力电池安装在回收的回填中，并在凯森（Caisson）下面替换的沙子，以监测液化的发生，这也可能成为重力caisson quay壁变形的主要原因。主要检查了前海底的物理特性，重力念珠的形状和正弦波的频率被用作重力凯森的地震力的频率。将地震力施加到30克离心机下的回填的Caisson码头壁上……更多。在回收的回填中发生了更多的诉讼，而部分液化发生在较高的沙子下，因为由于重力Caisson而导致的压力增加，因此在Caisson下方发生了更高的液化。由于惯性力，替换砂的轴承能力降低和回收后填充的动态压力，重力凯森（Caisson）随着额叶沉降向瓦砾丘移动。在此特定情况下，测得的Caisson的横向位移约为40 cm。考虑到规模效应，发现衍生的位移是有理由的，它通过比较了来自Nambu地震的成就。还使用“ LIQCA”代码来描述了离心机模型测试的性能。该代码的参数已根据实验室实验在离心机模型测试中使用的相同材料以及通过离心机模型测试的测量数据进行合理确定。从数值分析和离心机模型测试中进行了过滤并比较。两个过滤加速度都显示出很好的匹配。尽管计算出的位移略微高估了实验结果，但数值结果可以准确地描述实验结果，尤其是在回收后回填中过量孔隙水压的产生/耗散过程以及凯森（Caisson）下面的替换沙子。从这些结果来看，已发现使用离心机模型测试和本研究中采用的数值评估的程序对于评估重力凯森码头壁的原位性能很有用，并具有回收的回填。较少的