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Research on evaluation of sedimentation and consolidation properties of clay using RI-density log for dredging and reclamation

疏浚围垦用RI密度测井评价粘土沉降固结特性研究

基本信息

批准号：
15360250
负责人：
UMEZAKI Takeo
金额：
$ 3.39万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360250/
关键词：
dredged clay reclaimed ground settling consolidation density log cone penetration test elastic shear modulus shear strength ベンダーエレメントベーンせん断試験軟弱地盤ラジオアイソトープ

项目摘要

A series of settling column tests was carried out on a dredged clay. And continuously, constant rate of strain consolidation column tests were also conducted. During those tests, RI-density log was carried out simultaneously and in-depth profiles of ρ_t were measured. And then bender element tests and miniature vane shear tests were carried out for the clay with a wide range of water content. Based on test results, firstly, feasibility of RI-density log was investigated. Then, relations of f-log σ_v', w/w_L-logG and w/w_L-log s_u were evaluated, where f is specific volume, σ_v' is effective stress, w is water content, w_L is liquid limit, G is elastic shear modulus and s_u is shear strength. And finally, RI-density log was applied to field investigations in closed water body and reclaimed ground, and the adequateness of RI-density log for the investigations were discussed. Main conclusions are as follows.1. The feasibility of RI-density log in laboratory test is satisfactory. In each state of clear water, suspension, fluid mud, and bed mud (bottom sediment), the density can be measured with high accuracy, respectively.2. f-log σ_v' relation can be obtained by measurements of density and pore water pressure. The relation can be approximated by a straight line within w/w_L【approximately equal】1.5, and the value of the inclination of the line is almost equal to that of compression index C_c obtained from the standard laboratory test.3. w/w_L-logG relation can be approximated by a straight line within w/w_L【approximately equal】1.5. However, the value of the inclination differs from that of C_c.4. w/w_L-log s_u relation can be approximated by a straight line within w/w_L【approximately equal】1.5. Then, the value of the inclination is almost equal to that of C_c.5. The adequateness of RI-density log for field investigation is verified. Furthermore, a simple method to predict settlement curve of reclaimed ground was newly proposed.

在疏浚粘土上进行了一系列沉降柱试验。并连续进行了恒速应变固结柱试验。在这些测试过程中，同时进行了RI密度测井，并测量了ρ_t的深度剖面。在此基础上，对不同含水率的粘土进行了弯曲单元试验和微型叶片剪切试验。根据试验结果，首先对RI-密度测井的可行性进行了研究。计算了f-σ_v‘、w/w_L-logg和w/w_L-log S_u的关系式，其中f为比容，σ_v’为有效应力，w为含水率，w_L为液限，G为弹性剪切模数，S_u为抗剪强度。最后，将RI-密度测井应用于封闭水体和围垦土地的野外调查，并讨论了RI-密度测井在调查中的适用性。主要结论如下：1.本文主要结论如下。RI密度测井在室内测试中的可行性是令人满意的。在清水、悬浮物、浮泥和底泥(底泥)的每一种状态下，都可以高精度地测量密度。通过密度和孔压的测量，可以得到F-LOGσ_v‘关系。在w/w_L[约等于]1.5范围内，该关系可近似为一条直线，且该直线的倾斜度与由标准室内试验得到的压缩指数C_c的值几乎相等。W/W_L-Logg关系在W/W_L[近似等于]1.5时可用直线近似。然而，倾斜值与C_c_4的值不同。W/W_L-对数S_u关系可在W/W_L[近似相等]1.5内用直线近似。此时，倾角的值几乎等于C_c_5。验证了RI密度测井用于野外调查的充分性。在此基础上，提出了一种预测填海土地沉降曲线的简便方法。