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Discrete element numerical simulation of dynamic strength characteristics of expanded polystyrene particles in lightweight soil

  • Wei Zhou (College of Water Resources and Architectural Engineering, Northwest A&F University) ;
  • Tian-shun Hou (College of Water Resources and Architectural Engineering, Northwest A&F University) ;
  • Yan Yang (College of Water Resources and Architectural Engineering, Northwest A&F University) ;
  • Yu-xin Niu (College of Water Resources and Architectural Engineering, Northwest A&F University) ;
  • Ya-sheng Luo (College of Water Resources and Architectural Engineering, Northwest A&F University) ;
  • Cheng Yang (Hanjiang to Weihe River Valley Water Diversion Project Construction Co., Ltd.)
  • Received : 2022.09.23
  • Accepted : 2023.07.20
  • Published : 2023.09.10

Abstract

A dynamic triaxial discrete element numerical model of lightweight soil was established using the discrete element method to study the microscopic mechanism of expanded polystyrene (EPS) particles in the soil under cyclic loading. The microscopic parameters of the discrete element model of the lightweight soil were calibrated depending on the dynamic triaxial test hysteresis curves. Based on the calibration results, the effects of the EPS particles volume ratio and amplitude on the contact force, displacement field, and velocity field of the lightweight soil under different accumulated strains were studied. The results showed that the hysteresis curves of lightweight soil exhibit nonlinearity, hysteresis, and strain accumulation. The strain accumulated in remolded soil is mainly tensile strain, and that in lightweight soil is mainly compressive strain. As the volume ratio of EPS particles increased, the contact force first increased and then decreased, and the displacement and velocity of the particles increased accordingly. With an increase in amplitude, the dynamic stress of the particle system increased, and the accumulation rate of the dynamic strain of the samples also increased. At 5% compressive strain, the contact force of the particles changed significantly and the number of particles deflected in the direction of velocity also increased considerably. These results indicated that the cemented structure of the lightweight soil began to fail at a compressive strain of 5%. Thus, a compressive strain of 5% is more reasonable than the dynamic strength failure standard of lightweight soil.

Keywords

Acknowledgement

Project (51509211) supported by the National Natural Science Foundation of China; Project (2016M602863) supported by China Postdoctoral Science Foundation; Project (2018031) supported by the Excellent Science and Technology Activities Foundation for Returned Overseas Teachers of Shaanxi Province; Project (2015SF260) supported by the Social Development Foundation of Shaanxi Province; Project (2017BSHYDZZ50) supported by the Postdoctoral Science Foundation of Shaanxi Province; Project (2021JLM-51) supported by the Natural Science Foundation of Shaanxi Province; Project (SZ02306) supported by Shaanxi Key Laboratory of Safety and Durability of Concrete Structures, Xijing University; Project (XKLGUEKF21-02) supported by Xi'an Key Laboratory of Geotechnical and Underground Engineering, Xi'an University of Science and Technology; Project (2452020169) supported by the Fundamental Research Funds for the Central Universities.

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