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Study on Rational Design of Ground Solidification Methods as Countermeasures against Liquefaction

地面液化对策合理设计方法研究

基本信息

批准号：
13555136
负责人：
KOSEK Junichi
金额：
$ 3.39万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13555136/
关键词：
Liquefaction Countermeasures Cement Mixing Sand Triaxial Tests Splitting Tests Tensile Strength Seismic Design Ground Solidification

项目摘要

In order to evaluate rationally the tensile strength of cement-treated sands, a series of splitting tests, unconfined tension tests, and unconfined torsional shear tests were conducted and compared. The unconfined tension tests were conducted by using a newly developed testing system, which can transfer tensile force to the specimen through fixing devices by using gypsum as a filling material for the gap between the specimen and its holders. The fixing devices are attached to the top cap and the pedestal through universal joints that are inserted to reduce the bending moment applied unnecessarily to the specimen. As a result, the tensile strength obtained by the unconfined tension tests was larger than the one obtained by the conventional splitting tests, while the unconfined torsional shear tests largely underestimated the tensile strength. Such difference was possibly caused by different extents of progressive failure during each type of tests.In addition, a new plane strain compression testing system suitable for shearing stiff geomaterials and observing shear band formation was developed, and a series of both monotonic and cyclic loading tests were conducted on rectangular prismatic specimens of cement-treated sand. Comparisons were made between monotonic and cyclic plane strain compression tests to evaluate the differences on the peak strength of specimens with and without a cyclic loading history. No evidence of a reduction in the peak strength of specimens subjected to large amplitude cyclic loading was found. To study strain localisation characteristics and their relation with the failure mechanism of cement-treated sand, maximum shear strain distributions were calculated based on digital photographs taken at different stages of loading during each test.

为了合理评价水泥稳定砂的抗拉强度，进行了劈裂试验、无侧限拉伸试验和无侧限扭剪试验，并进行了对比。采用石膏作为试件与夹具之间差距的填充材料，通过固定装置将拉力传递给试件，利用新开发的无侧限拉伸试验系统进行了无侧限拉伸试验。固定装置通过万向接头连接到顶盖和基座上，万向接头插入以减少施加到试样上的不必要的弯矩。结果表明，无侧限抗拉试验得到的抗拉强度大于常规劈裂试验得到的抗拉强度，而无侧限扭剪试验大大低估了抗拉强度。另外，本文还开发了一套适合于刚性岩土材料剪切和剪切带形成的平面应变压缩试验系统，并对水泥稳定砂矩形棱柱体试件进行了单调和循环加载试验。比较了单调和循环平面应变压缩试验，以评估有和没有循环加载历史的试样的峰值强度的差异。没有证据表明，在峰值强度的试样进行大幅循环loading.To研究应变局部化特性及其与水泥处理砂的破坏机制的关系，最大剪切应变分布的基础上，在不同阶段的加载在每个测试中拍摄的数码照片计算。