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Mechanism of germination of underground cavities and its influence on pavement

地下空洞萌发机理及其对路面的影响

基本信息

批准号：
11450182
负责人：
MOCHIZUKI Akitoshi
金额：
$ 5.25万
依托单位：
The University of Tokushima
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 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11450182/
关键词：
pavement under-road cavity CBR test cenrifuge model test compaction erosion due to water permeation 支持力 (遠心)模型実験

项目摘要

The following themes were objects in this project using experimental and analytical procedures: Theme-1 Simulation of a process to form a cavity in a sandy layer due to water permeation by experiments in laboratory. Theme-2 Development of Stability Test Method of back filling materials for a road excavation, and a guideline of the degree of compaction to avoid subsidence of a road due to a cavity underneath pavements. Theme-3 Development of a centrifugal apparatus for soil model tests with observing systems for deformation of models and distribution of stresses in the centrifuge. Theme-4 Performance of centrifugal model tests to simulate a process of failure of a clayey pavement with a cavity by self-weight. Theme-5 Bearing capacity tests of a clay ground with a cavity. Theme-6 Analyses of bearing capacity of clay ground with a cavity.Firstly, the process to form a cavity was demonstrated in a series of model tests. Then Stability Test of back-fill materials using a compaction mold wit … More h 13 holes measuring 10 mm in diameter at the bottom plate was developed. The results showed that the resistance of materials for de-compaction depended on basically grain size distribution, and that over 85 % of the degree of compaction of material is effective to prevent de-compaction.A new centrifuge apparatus with a 400 g-t capacity and an effective radius of 1.55 m was developed with a support from this grant aid. The relationship between the tensile strength and the width of collapsed underground cavities was investigated and an equation to predict the shape of collapsed ceiling was proposed. In theme-5 and 6, bearing capacity tests for model ground on an artificial clay with/without a cavity were performed in the gravitational field, and a chart was obtained, which shows a relationship of bearing capacity to depth and width of a cavity in the ground.Analyses for the footing tests on model clay were performed, and obtained result that if a cavity locates over three times of a footing width, bearing capacity of the ground is, the same as that on a clay ground without any cavity. The same conclusion was obtained in the bearing capacity tests on the artificial ground. According to the conclusions, a risk chart for under-road cavity was presented based on data sampled in Osaka city area. Less

以下主题是本项目使用实验和分析程序的对象：主题-1模拟由于实验室中的水渗透而在桑迪层中形成空腔的过程。主题-2道路开挖回填材料稳定性试验方法的开发，以及压实度指南，以避免因路面下方空洞而导致道路沉降。主题-3开发用于土模型试验的离心装置，并带有模型变形和离心机中应力分布的观测系统。主题-4离心模型试验的性能，以模拟粘土路面因自重而产生空洞的破坏过程。专题-5含空洞粘性土地基承载力试验。专题六含空洞粘性土地基承载力分析首先，通过一系列模型试验论证了空洞的形成过程。然后，利用具有不同压实度的压实模具进行回填材料的稳定性试验， ...更多信息在底板上形成13个直径为10 mm的孔。结果表明，物料的反压阻力基本上取决于物料的粒度分布，85%以上的物料压实度对反压有效。在该项目的资助下，研制了一台处理能力为400 g-t、有效半径为1.55 m的新型离心机。研究了顶板抗拉强度与塌陷孔洞宽度的关系，提出了顶板塌陷形状的预测公式。课题5和课题6在重力场条件下进行了有、无空洞的人工粘土模型地基承载力试验，得到了地基承载力与空洞深度和宽度的关系图，并对模型地基基础试验进行了分析，得出了当空洞位于基础宽度的3倍以上时，地基承载力与无空洞粘土地基相同。人工地基承载力试验也得到了同样的结论。在此基础上，以大坂市为例，给出了道路空洞的风险图。少