Collapse Behavior of Compacted Clays in Suction-Controlled Triaxial Tests
Sun, DA
Department of Civil Engineering, Nagoya Institute of Technology, Nagoya, Japan

Matsuoka, H
Department of Civil Engineering, Nagoya Institute of Technology, Nagoya, Japan

Xu, YF
School of Civil Engineering and Mechanics, Shanghai Jiaotong University, Shanghai, China

(Received 3 May 2002; accepted 19 December 2003)

Abstract
Using a suction-controlled triaxial apparatus for unsaturated soils, a series of tests on a compacted clay was performed to investigate the influences of stress states, water content, void ratio, and matric suction on the collapse behavior. The triaxial tests were carried out under the conditions of (1) different stress ratios and mean stresses, (2) triaxial compression and extension, (3) different initial void ratios of specimens with the same water content, (4) different initial water contents with the same degree of compaction, and (5) different controlled matric suctions. The main conclusions were obtained as follows: (1) The volume change induced by the collapse mainly depends on the initial void ratio and mean net stress under which the collapse occurs, irrespective of imposed matric suction; (2) the amount of collapse is small at both low and high confining stresses, and there exists a maximum value of collapse at a particular mean stress; (3) the shear strain increment induced by collapse depends on stress ratio, triaxial compression, or extension stress; (4) when imposed suction is decreased, large collapse deformation takes place in the samples compacted dry-of-optimum, while little collapse deformation takes place in the samples compacted wet-of-optimum; and (5) the collapse behavior can be explained by the elastoplastic theory for unsaturated soils.

Keywords:
clays, collapse, compacted soil, stress ratio, suction, triaxial test, unsaturated soil

Paper ID: GTJ11418
DOI: 10.1520/GTJ11418

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Author Sun, DA Affiliation Department of Civil Engineering, Nagoya Institute of Technology, Nagoya, Japan Author Matsuoka, H Affiliation Department of Civil Engineering, Nagoya Institute of Technology, Nagoya, Japan Author Xu, YF Affiliation School of Civil Engineering and Mechanics, Shanghai Jiaotong University, Shanghai, China Author Sun DA, Matsuoka H, Xu YF Title Collapse Behavior of Compacted Clays in Suction-Controlled Triaxial Tests Symposium , Committee on