2005 Fiscal Year Final Research Report Summary
Research on evaluation of sedimentation and consolidation properties of clay using RI-density log for dredging and reclamation
| Project/Area Number |
15360250
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Shinshu University |
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Principal Investigator |
UMEZAKI Takeo Shinshu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (50193933)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAMURA Takashi Shinshu University, Faculty of Engineering, Research Associate, 工学部, 助手 (50324231)
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| Project Period (FY) |
2003 – 2005
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| Keywords | dredged clay / reclaimed ground / settling / consolidation / density log / cone penetration test / elastic shear modulus / shear strength |
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| Research Abstract |
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.
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Research Products
(9 results)
