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A study on measuring method of in-situ Ko-value for sandy and gravelly soils

砂砾土Ko值原位测定方法研究

基本信息

批准号：
14350307
负责人：
HATANAKA Munenori
金额：
$ 8.64万
依托单位：
Chiba Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14350307/
关键词：
sandy soil reclaimed land Ko-value in-situ freezing sampling method undisturbed sample liquefaction strength sand compaction method in-situ test 礫地盤静止士圧係数

项目摘要

It is very important to know the in-situ stress of soils, because the strength and deformation characteristics of soils are significantly affected by stress level. Unfortunately, until now, there is no efficient method was developed for measuring the in-situ horizontal stress of sandy and gravelly soils. A new method was developed in the present study to measure the horizontal stress in sandy and gravelly soils. A cylindrical shape test probe, with 6 load transducers mounted on the outside surface of the test probe was installed into the frozen ground hole, which was made by coring the frozen ground to obtain high-quality undisturbed samples. After the probe was installed into the frozen ground hole, the frozen ground was allowed to thaw. When, the frozen ground was completely thawed, the stress measured by load transducers show the horizontal stress in the ground. The effect of temperature change of ground during thawing and the hydraulic pressure were canceled. Field test were perfor … More med at a reclaimed land located at Tokyo Bay. Though the preliminary test, the test probe was found to have some electric troubles. It was refined and used in main test for reclaimed land after it was stabilized by Sand Compaction Method. The Ko-value of the compacted sandy soil measured by the present method was ranging 0.41 to 0.98. These values are well consistent with the Ko-value(0.92-1.06) obtained by using Vs-equivalent method using high quality undisturbed samples which is also proposed previously by the authors. These results indicate that the proposed method developed in the present study is useful for measuring the in-situ horizontal stress for sandy and gravelly soils. Based on the internal friction angle obtained from CD tests on high-quality undisturbed samples of reclaimed land before compaction, Ko-value was estimated to be 0.38 by using Jaky's equation. These results firstly show that the Ko-value of the reclaimed land increased from 0.38 to about 1.0 due to sand compaction. Less

土的强度和变形特性受应力水平的影响，因此，了解土的地应力是非常重要的。遗憾的是，迄今为止，还没有有效的方法来测量现场水平应力的桑迪和砾石土。本文提出了一种新的测量桑迪和砾石土水平应力的方法。将一个圆柱形的测试探头安装在测试探头的外表面上，并在测试探头的外表面上安装了6个载荷传感器，该测试探头通过对冻土取芯而制成，以获得高质量的原状样品。在将探头安装到冻土孔中之后，允许冻土解冻。当冻土完全融化时，荷载传感器测得的应力反映了冻土中的水平应力。该方法消除了融冰过程中地温变化和水压力的影响。进行了田间试验 ...更多信息位于东京湾的填海造地。通过初步测试，发现测试探头存在电气故障。经砂击法加固后，进行了改良，并用于复垦地的主要试验。用本方法测得的压实桑迪的Ko值在0.41 ~ 0.98之间。这些值与作者以前提出的用高质量原状样品用Vs-等效法得到的Ko值（0.92-1.06）是一致的。这些结果表明，在本研究中提出的方法是有用的测量原位水平应力的桑迪和砾石土。根据压实前吹填土地高质量原状土样CD试验获得的内摩擦角，利用Jaky公式估算Ko值为0.38。这些结果首先表明，由于砂土压实，复垦土地的Ko值从0.38增加到约1.0。少