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Partic. vol. 35 pp. 68-77 (December 2017)
doi: 10.1016/j.partic.2017.02.002

Critical state shear behavior of the soil-structure interface determined by discrete element modeling

Xiaoqiang Gua, b, Yuanwen Chena, b, Maosong Huanga, b, *

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mshuang@tongji.edu.cn

Highlights

    • Shear behavior of soil-structure interface was investigated by DEM. • The shear deformation was mainly localized in a shear band near the soil-structure interface. • DEM results revealed the existence of a critical state in the shear band at large displacement. • Thickness and void ratios of shear band at critical state decreased with increasing normal stress.

Abstract

The interface between soil and structure can be referred to as a soil-structure system, and its behavior plays an important role in many geotechnical engineering practices. In this study, results are presented from a series of monotonic direct shear tests performed on a sand-structure interface under constant normal stiffness using the discrete element method (DEM). Strain localization and dilatancy behavior of the interface is carefully examined at both macroscopic and microscopic scales. The effects of soil initial relative density and normal stress on the interface shear behavior are also investigated. The results show that a shear band progressively develops along the structural surface as shear displacement increases. At large shear displacement a unique relationship between stress ratio and void ratio is reached in the shear band for a certain normal stress, indicating that a critical state exists in the shear band. It is also found that the thickness and void ratio of the shear band at the critical state decreases with increasing normal stress. Comparison of the DEM simulation results with experimental results provides insight into the shear behavior of a sand-structure interface and offers a means for quantitative modeling of such interfaces based on the critical state soil mechanics.

Graphical abstract

Keywords

Discrete element method; Interface; Direct shear test; Shear band; Dilatancy; Critical state