A micro-investigation on water bridge effects for unsaturated granular materials with constant water content by discrete element method--颗粒学报PARTICUOLOGY

Li, M., Luan, J., Gao, X., Wang, J.-P., & Dadda, A. (2023). A micro-investigation on water bridge effects for unsaturated granular materials with constant water content by discrete element method. Particuology, 83, 50-62. https://doi.org/10.1016/j.partic.2023.02.006

A micro-investigation on water bridge effects for unsaturated granular materials with constant water content by discrete element method

Mengchen Li, Jiyuan Luan, Xuguang Gao, Ji-Peng Wang^*, Abdelali Dadda

School of Civil Engineering, Shandong University, 17922 Jingshi Road, Jinan, 250061, China

10.1016/j.partic.2023.02.006

Volume 83, December 2023, Pages 50-62

Received 29 August 2022, Revised 2 February 2023, Accepted 6 February 2023, Available online 24 February 2023, Version of Record 13 March 2023.

E-mail: ji-peng.wang@sdu.edu.cn

Highlights

• Verify the rationality of simplification of the stress-force-fabric (SFF) relationship.

• Study the effect of saturation on unsaturated granular materials by DEM.

• Use SFF relationship to interpret the macroscopic mechanical behavior.

• Capillary force anisotropy cannot be ignored in the SFF relationship simplification.

• Different water bridge models would not change the characteristics of the solid skeleton.

Abstract

The most common state of surface soil is unsaturated. Changes in water content will substantially impact its strength, leading to geological and engineering catastrophes. This paper used LIGGGHTS software to simulate the water bridge effect of unsaturated granular materials with constant water content and verify the rationality of the simplification of the stress-force-fabric (SFF) relationship. The results showed that the capillary force was not isotropic, which was different from the previous study, thus it cannot be overlooked in the simplification of the SFF relationship. Moreover, the influence of water content on the macroscopic mechanical behavior of unsaturated granular materials was interpreted through the evolutions of coordination number, interparticle force, fabric and force anisotropy, and other microscopic parameters. Compared to the literature, we found that different water bridge models would not change the characteristics of the solid skeleton.

Graphical abstract

Keywords

Unsaturated granular material; Water bridge effect; Water content; Discrete element method; Stress-force-fabric (SFF) relationship

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