Development of image analysis system for geotechnical laboratory testing and its application for understanding of mechanism of bearing capacity mobilization of crushable materials

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 16560431
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Geotechnical engineering
• Research Institution: Yamaguchi University
• Principal Investigator: MURATA Hidekazu Yamaguchi University, Department of civil engineering, Professor, 工学部, 教授 (80044618)
• Co-Investigator(Kenkyū-buntansha): HYODO Masayuki Yamaguchi University, Department of civil engineering, Professor, 工学部, 教授 (40130091) ; NAKATA Yukio Yamaguchi University, Department of civil engineering, Associate professor, 工学部, 助教授 (90274183) ; YOSHIMOTO Norimasa Yamaguchi University, Department of civil engineering, Research associate, 工学部, 助手 (00325242)
• Project Period (FY): 2004 – 2005
• Keywords: PIV / crushable material / bearing capacity / triaxial compression / local deformation

Research Abstract

In order to clarify the effects of soil crushablity on the engineering aspects such as field investigation, the following points were studied for this two years.
(1) to develop the measurement system on soil grain movement using image analysis
(2) to apply the system in (1) to soil laboratory testing and to understand local deformation during test
(3) to apply the system in (1) to footing loading tests in small model and to record the local displacement near the footing plate
(4) to understand the relationship between soil crushability and local displacement on the basis of the result of (2) and (3)
The obtained results were as follows ;
(1) The measurement system to be able to know a grain movement were developed
(2) The system was applied to a triaxial compression test to measurement the three dimenstional movement of the targets on the specimens surface. The measurent allowed to investigate the behaviour of shear band formation during test. The shear band of Ube masado was observed to form with decreasing its thickness.
(3) The effects of soil crushability on the bearing capacity in shallow foundation were investigated. The image analysis was also appled to the model loading tests on the foundation. The localization of shear deformation and the progressive failure were observed depending on the soil properties. So the general shear failure was observed for the soil which have dilative volume change while the local shear failure for contractive materials.