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An investigation on effects of countermeasures against liquefaction of sand deposits with structures

建筑物砂沉积物液化对策效果研究

基本信息

批准号：
07555445
负责人：
TAKEMURA Jiro
金额：
$ 1.28万
依托单位：
Tokyo Institue of Technoloty
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555445/
关键词：
liquefaction sand oil tank embankment model test sheet pile wall gravel drain settlement 矢板壁バーチカルドレーン矢板

项目摘要

Centrifuge model tests are carried out to study the effect of various countermeasures against liquefaction of sand deposits with an undergrond structure and a structure on surface. Model tests are conduced on five types of models ; one without any countermeasures and four with countermeasures ; sheet pile walls with or without drainage capability, sheet pile walls of which tops are tied with rods and gravel drains.Following conludsions are drawn from this study.1.For foundation soil with an underground structure, upward movements of it take place when excess pore pressure beneath the structure reaches a threshold value. In countermeasures to prevent the upward movement, an attempt should be made to keep the excess pore pressure lower than this threshold.2.Responses of acceleration of structures depend very much on the excess pore pressures generated in foundation soil. The acceleration responses at the very early stages of input motons are similar for all the cases, but the subsequcnt responsese differ for different types of countermeasure. For the cases without drainage, the acceliration of structure decreases with the generation of excess pore pressure. On the other hand, for the cases with drainage, the acceleration of structure increase.3.Settlements of structures on a ground surface like oil tank and embankment arise from two reasons ; the compression of sand beneath due to consolidation and the other the lateral movement of hte sand. Increase of lateral movement gives rise to an increase in total settlements of the structure, suppression of lateral spreading is necessary.

本文通过室内模型试验，研究了不同处理措施对具有地表结构和地下结构的砂土地基液化的影响。本文通过对五种不同类型的模型（一种无加固措施，四种有加固措施，有无排水能力，桩顶拉杆和碎石排水板）进行了试验研究，得出以下结论：1.对于地下结构地基土，当结构下超静孔压达到一定值时，地基土发生向上运动;在防止地基土向上运动的措施中，应尽量使超静孔隙水压力低于该限值。2.结构的加速度响应很大程度上取决于地基土中产生的超静孔隙水压力。在所有情况下，输入电动子的非常早期阶段的加速度响应是相似的，但是对于不同类型的对抗措施，随后的响应是不同的。在不排水的情况下，结构的加速度随着超静孔压的产生而减小。3.油罐、路堤等地面上结构物的沉降主要由两个原因引起：一是地基固结对砂土的压缩，二是砂土的侧向移动。横向位移的增加会引起结构总沉降的增加，因此必须抑制结构的横向扩展。