Characterization of low placement ratio SCP and deformation of SCP ground under backfilled

低安置率SCP特征及回填下SCP地面变形

基本信息

批准号：
11650501
负责人：
TAKEMURA Jiro
金额：
$ 2.24万
依托单位：
Tokyo Institute of Technology
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

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650501/
关键词：
soft clay sand compaction piles caisson type quay wall centrifuge model tests light weight material cavity expansion theory cone penetration

项目摘要

Short and long term behavior of soft clay improved by sand compaction piles with low replacement ratios, which is subjected to backfilled caisson loading, have been investigated through a series of centrifuge model tests. In the model tests the construction sequence from the installation of the caisson to the backfilling was simulated in-flight. Effects of replacement ratio, A_s, improvement width, SCP location and loading rate on the behavior of the caisson were studied. From the model tests the following were derived :(1)Both during and after back filling, settlement of the caisson can be effectively reduced by higher replacement ratio. The settlement of caisson after backfilling is highly influenced by the settlement of the ground behind the SCP portion.(2)Wider improvement area towards the fill is more effective in reducing the lateral displacement of the caisson both during and after backfilling and the degree of consolidation of clay part in SCP ground has a significant effect on … More the short-term lateral deformation.(3)Using light-weight material as the back fill, both short-term stability and long-term settlement behavior can be effectively improved.Furthermore, by using cavity expansion theory, theoretical equations on the cone tip resistance and shaft resistance were derived, in which the effect of replacement ratio of the SCP is taken into account as the stiffness of spring assumed surrounding a SCP. The effect of replacement ratio on the stiffness was investigated by pressure-meter tests and applicability of the derived equation was examined by cone penetration tests in the SCP with different replacement ratio in the centrifuge. From these studies, the followings were obtained :(4)Subgrade reaction, k_h, of SCP is much smaller than the uniform sand with same density and the k_h, decreases with decreasing replacement ratio. As a result, the cone tip resistance and shaft resistance decrease with decreasing A_s.(5)Comparing the calculated cone tip and shaft resistance with the observations, the possibility of the determination of fiction angle of SCP from the cone resistances was confirmed. Less

通过一系列离心机模型测试研究了较低的替代比的砂钢钢琴的短期和长期行为，其替换率较低的砂钢琴受到了回填充的caisson载荷。在模型测试中，从飞行中模拟了从安装到回填填充到回填的构造顺序。替换比，A_S，改进宽度，SCP位置和加载速率对Caisson行为的影响是研究的。从模型测试中得出以下内容：（1）在回填期间和回填后，可以通过较高的替换比有效地降低CAISSON的设置。回填后的凯森（Caisson）的设置受到SCP部分背后的地面设置的高度影响。（2）在填充过程中和填充期间和之后，更广泛的改进区域更有效地减少Caisson的横向位移，无论是在SCP地面上的粘土部分巩固程度，并且在短期填充上都具有更大的材料，因为它均具有更大的材料。通过使用空腔扩展理论，得出了锥尖抗性和轴电阻的理论方程，在这种情况下得出了SCP的替换比的影响，因为将SCP的替换比的影响考虑到SCP周围的SCP的刚度，因此可以考虑到SCP的僵硬，从而得出了长期的设定行为。通过压力表测试研究了替换比对刚度的影响，并通过在离心机中的SCP中的锥渗透测试中检查了衍生方程的适用性。从这些研究中，获得了以下内容：（4）SCP的子级反应K_H比均匀的砂小得多，密度相同，而K_H的均匀量会随降低的替代比而降低。结果，随着A_S的降低，锥形尖端电阻和轴电阻会降低。（5）将计算出的锥形尖端和轴电阻与观测值进行比较，确定了SCP从锥体抗性中测定SCP的虚构角度的可能性。较少的