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

通过一系列中心测试，已经研究了由较低的替换比的砂桩组成的短期和长期行为从模型测试中进行了研究：（1）在填充期间和之后，可以通过较高的替换比有效地降低了SCP部分的地面。在SCP地面部门中CLT合并的期间和反填充物都可以通过腔扩张理论来衍生出短期的横向变形。，随着SCP周围的弹簧的刚度，替换率对替换比的刚度对替换量的刚度进行了考虑。在特朗普中央的SCP中，SCP的锥体渗透测试得到了以下内容：（4）SCP的子级反应K_H较小，均匀的沙子具有相同的密度和相同的K_H，有些放心的替代比结果，锥形电阻和轴电阻随着A_S的降低而降低，将计算出的锥体与观测值进行了比较，确定了SCP FRE C的SLESLE的可能性