权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study of Seepage Characteristic Testing Method for Unsaturated Soils By Controlling Air Pressure

控制气压非饱和土渗流特性测试方法研究

基本信息

批准号：
11555126
负责人：
UNO Takano
金额：
$ 3.33万
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-11555126/
关键词：
Coefficient of Permeability Uni-axial Compression Strength Unsaturated Soils Pore Size Distribution Moisture Holding Characteristic Curve Gradation Composite Testing Apparatus for Seepage and Compression Air Intrusion Method.不飽和土、不飽和透水

项目摘要

In this study, three topics have been examined concerning with the seepage testing method developed as the stationary flow through unsaturated soils. ( 1 ) Accumulation of data in the unsaturated seepage characteristics, ( 2 ) study on the relationship between seepage characteristics and soil properties including grain size characteristics, ( 3 ) development of composite testing apparatus for seepage and compression and its utility.( 1 ) Accumulated data are, 1) moisture holding characteristic curve, 2) coefficient of permeability for unsaturated soils to the degree of saturation, and 3) coefficient of air flow. Ten kinds of soils are following as Toyoura Standard sand, the Nagara sand, coarse sand, silt, roam and so on.( 2 ) The relationship between the grain size distribution ( 50 % diameter, diameter estimating grain size distribution, etc. ) and moisture holding characteristic values ( air entry value, specific moisture holding capacity, etc. ) are examined to establish the proposed formula with good accuracy among many equation like the Haverkanmp method and the van-Genuchuten method. Among these results, it is clear that air entry value is in reverse proportion to the diameter estimating grain size distribution, and that the pore diameter indices and the specific capacity are strongly dependent to the coefficient of uniformity.( 3 ) As a result of the composite testing apparatus for seepage and compression, permeability and strength of silt are depended on the degree of saturation, as was found in former study of tested specimens respectively. A sample of results is that the uni-axial compression strength is in reverse proportion to the logarithm of coefficient of permeability, and that stress-strain relationship varies from brittle to ductile at certain water content.

在这项研究中，有三个主题是关于渗流试验方法的，该方法是作为恒定流通过非饱和土体发展起来的。(1)非饱和渗流特性数据的积累；(2)渗流特性与土壤性质(包括粒度特性)之间关系的研究；(3)渗流压缩复合测试仪的研制及其应用。(1)积累的数据是：1)持水特性曲线，2)非饱和土体饱和程度的渗透系数，3)空气流动系数。10种土壤分别为Toyoua标准砂、Nagara砂、粗砂、粉砂、漫滩等。(2)粒度分布(50%直径、直径估算粒度分布等)之间的关系。和保湿特性值(进气值、比保湿容量等)。通过对哈弗坎普法和van-Genuchuten法等多个方程的检验，建立了精度较高的公式。其中，进气值与反映颗粒大小分布的直径成反比，孔径指数和比容与均质系数有很强的相关性。(3)由于复合渗透和压缩试验装置的结果，粉土的渗透性和强度都依赖于饱和程度，这一点在以往的试验样品研究中得到了证实。结果表明，单轴抗压强度与渗透系数的对数成反比，在一定含水率下，应力应变关系由脆性变为延性。