Development of the methods of safety evaluation in land improvement facilities

土地改良设施安全评价方法的开发

基本信息

批准号：
11556042
负责人：
SHIMIZU Hideyoshi
金额：
$ 2.37万
依托单位：
Gifu University
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-11556042/
关键词：
see page failure two dimensional concentrated flow fracture toughness hydraculic fracturing wedge insertion experiment tensile 80ftening curve probability of liguefaction ground improvement 縦亀裂破壊力学軸対称流破壊パラメータ水理破砕 Prismatic fa

项目摘要

1. Safety evaluation in seepage flow The safety factor to the seepage failure of the foundation ground is defined by using the prismatic failure concept. The limit water head is analyzed in case- of two dimensional concentrated flow by varying the setting depth of sheet piles and the width of digging of ground. As a result, it is clarified that the smaller the width of digging and the deeper the setting depth is, the more decreasing the stability to the seepage becomes. In addition, it is also shown that the stability of the ground decreases when the ratio ofanisotopic:2. Hydraulic fracturing in fill material Considering the tensile failure generally occurs in the material when its character changes, soil is thought to cause a similar mannec Tri-axial compression tests are conducted on samples taken from a foundation in a small earth dam to examine the generation of the vertical crack with varying water content As a result, it is confirmed that a vertical crack occurs at a considerably … More early stage and lower water content in the experiment, so it suggests the hydraulic fracturing possibly occurs when reservoir water level rises.3. Safety evaluation in concrete structures The wedge insertion technique under two axial stresses is performed. In two types of concrete with river gravel and crushed stone, each breaking energy is obtained from the measurement of load-opening displacement As a result it is clarified that the breaking energy decreases compared with the case of the uniaxial stress, and the one with crushed stone is larger than that with the river gravel. In addition, the multi straight line approximation method is applied from the measurement data. It is also shown that the shape of softening curve differs each other, and the Young's moduli decrease, increasing in the compressive stress ratio.4. Reliability design of reclamationtlvke A calculation method of probability of liquefaction in reclamation dyke is proposed considering the spatial variability of soil parameters for the dynamic strength, N-values, median grain size, fine contents and the statistical characteristics of the earthquake occurrence. Using this method, the reliability design of the sand compaction piles is discussed for the ground improvement against the liquefaction. As a result, it is shown that the optimum sand replacement rate is determined so as to minimize the total cost Less

1 渗流安全性评价利用棱柱破坏概念定义了地基渗流破坏的安全系数，通过改变板桩的埋设深度，分析了二维集中流情况下的极限水头。结果表明，开挖宽度越小，沉降深度越深，渗流稳定性就越差。当地面减小时填充材料中的各同位素比：2 考虑到材料特性变化时通常会发生拉伸破坏，因此认为土壤会引起类似的曼纳克。对取自小型土坝地基的样品进行了三轴压缩试验。考察不同含水量下垂直裂缝的产生结果，实验证实垂直裂缝发生在相当早的阶段且含水量较低，因此表明当储层有水时可能发生水力压裂。等级3. 混凝土结构的安全性评估在两种轴向应力下进行楔插入技术，通过测量荷载张开位移来获得每种断裂能。阐明了与单轴应力情况相比，破碎能有所降低，并且碎石的破碎能大于河卵石的破碎能，此外，从测量数据中还应用了多直线近似法。软化的形状4．围填海堤坝的可靠性设计考虑到土体动态强度参数N-的空间变异性，提出了一种围填海堤坝液化概率的计算方法。利用该方法，对地基加固的压实砂桩的可靠性设计进行了探讨。表明最佳砂替代率的确定使得总成本最小化少