A research adaptability and practical application of Compacted Bulb Foundation Method

压实球地基法的研究适应性及实际应用

基本信息

批准号：
09555154
负责人：
TAKADA Naotoshi
金额：
$ 2.88万
依托单位：
Osaka City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09555154/
关键词：
Bearing capacity Spread foundation Coefficient of subgrade reaction Centrifuge mode test Impact load Compaction Sandy soil Innovative technique 地盤変形

项目摘要

Heavy tamping is one of ground improvement technique for loose sandy and gravelly ground and rock waste fill. This method generally aims at uniformly compacting the whole ground, however, we found that a high density compacted area bulbously grew up beneath the tamping point by ram blow. The purpose of this study is to investigate the adaptability and practical application of 'Compacted Bulb Foundation Method', which applies heavy tamping to the spread foundation. Firstly a series of centrifuge model tests was carried out to investigate effects of kind of soils on bearing capacity of compacted bulb foundation. Secondly a series of centrifuge model tests was carried out to investigate effects of tamp condition ( ram mass, ram base area, drop height and number of blows) and foundation bed area on the bearing capacity characteristics in miniaturizing this method in order to use practically.Main conclusions are as follows : 1) within the material which changed maximum grain size and fine content which used this study, there is seldom the effect of kind of soils on this method, 2) it is possible to obtain sufficiently large bearing capacity, even if the tamp condition is miniaturized, 3) the bearing capacity of the compacted bulb is more dependent on total momentum than total tamping energy, 4) coefficient of subgrade reaction is larger, as ram base area is larger. From these results, the following are proposed : design method in using compacted bulb foundation method practically, necessary condition of the construction machine and construction management technique.

强夯是松散砂砾石地基及石渣填埋的地基改良技术之一。这种方法通常旨在均匀压实整个地面，然而，我们发现，通过夯击，在夯实点下方会出现球根状的高密度压实区域。本研究的目的是调查“压实球基础法”的适应性和实际应用，该法对铺展的地基进行强夯实。首先进行了一系列离心模型试验，研究不同土质对压实球根地基承载力的影响。其次，进行了一系列离心机模型试验，研究了捣固条件（滑枕质量、滑枕底面积、下落高度和打击次数）和基床面积对承载力特性的影响，以将该方法小型化以供实际使用。主要结论如下：1）在本研究中改变最大粒径和细粒含量的材料中，土体种类对这种方法的影响很少，2）可以获得足够大的承载力，即使如果夯实条件小型化，3）压实球的承载能力更依赖于总动量而不是总捣固能，4）随着夯底面积的增大，路基反力系数也更大。根据这些结果，提出了以下几点：实际应用压密球基础法的设计方法、施工机械的必要条件和施工管理技术。