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Clarification of complex microstructural changes consisting of solid, liquid and gas phases governing deformation and failure of soils

Project Gist

Clarify complex microstructural changes of soils consisting of solid, liquid and gas phases

Keywords

soil, multi-phase mixture, microstructural change, x-ray computed tomography

Background, Purpose, and Project Achievements

Soils are composed of soil particle, water and air microscopically, and the structures are complex. As for “unsaturated soil” whose voids are partially saturated by water, interfaces between the water and the air forms menisci on which negative pore water pressure referred as suction increases the inter-particle forces. On the other hand, breakdown in the suction e.g., by the infiltration of water due to rainfall and/or shearing due to earthquake, induces a large loss in strength involving clear failure surface. It is therefore important to know the mechanism of change of suction acting between soil particles since suction significantly affects overall stiffness of soil. This project aims to reveal the complex microstructural changes using micro x-ray tomography technique through joint research between Kyoto University and Laboratoire 3SR, Grenoble, France.

Future Prospects

Micro x-ray tomography and the image analysis technique will clarify unknown mechanism of microstructural changes of soil. In addition, based on the obtained findings, we will try to propose new modeling scheme to develop a robust method to predict deformation of soils.

Figures

Microstructure of unsaturated soil (yellow: soil particles, blue: pore water, black: pore air)
X-ray CT images of deformation of soil and their three-dimensional strain field analyzed by digital image correlation analysis

Principal Investigator

HIGO Yosuke

・HIGO Yosuke
・Department of Urban Management, Graduate School of Engineering
・Major research interest is to clarify a link between the microscopic and macroscopic behaviors of geomaterials through experiments using x-ray tomography technique. Furthremore, we are developing analysis methods based on the physical background obtained by the experimental study to predict macroscopic geotechnical issues such as geoharzards induced by rainfalls and earthquakes.
http://www.um.t.kyoto-u.ac.jp/ja/information/laboratory/GeofrontSystemEngineering