Macroscopic Behavior and Microscopic Structure Evolution of Marine Clay in One-Dimensional Compression Revealed by Discrete Element Simulation

Lisha Luo,Zhifu Shen,Hongmei Gao,Zhihua Wang,Xin Zhou

doi:10.3390/pr9122259

Lisha Luo, Zhifu Shen + Show 3 more

Open Access

https://doi.org/10.3390/pr9122259

Copy DOI

Journal: Processes	Publication Date: Dec 14, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Open University of Hong Kong, Nanjing Tech University

Abstract

Marine clay has been attracting in-depth research on its mechanical behavior and internal structure evolution, which are crucial to marine infrastructure safety. In the formation process of marine clay, including the sedimentation and consolidation stages, the compression behavior and internal structure evolution are highly dependent on the pore water salinity. Discrete element method (DEM) simulation is a powerful tool to study the microscopic mechanics behind the complicated macroscopic mechanical behavior of marine clay. In this study, a DEM simulation scheme is systematically proposed to numerically study the macroscopic beahvior and microscopic structure evolution of marine clay in one-dimensional compression that mimics the marine clay formation process. First, the proposed calculation scheme for double layer repulsive interaction and van der Waals interaction is introduced. Then, the developed DEM simulation scheme is validated by satisfactorily reproducing the experimentally observed one-dimensional compression curves and internal structure transition from an edge-to-edge/edge-to-face flocculated structure to a face-to-face dispersed structure. Finally, evolutions of coordinate number and fabric anisotropy are quantitatively evaluated in the microscopic view. The noticeable effects of ion concentration on the internal structure evlotion and mechanical behavior of marine clay have been examined and discussed.

Highlights

Published: 14 December 2021Marine clays are widely distributed along the coastal lines where large amounts of infrastructure are in service or under construction
A complete understanding of the physical and mechanical behavior of marine clay is crucial to infrastructure safety under varying conditions, such as pore water salinity change, depositional process alternation, wave loading, etc
The complicated behavior of marine clay is mainly attributed to its initial microscopic structure and the evolution of its structure upon chemical, thermal, or mechanical disturbance

Summary

Introduction

Published: 14 December 2021Marine clays are widely distributed along the coastal lines where large amounts of infrastructure are in service or under construction. A complete understanding of the physical and mechanical behavior of marine clay is crucial to infrastructure safety under varying conditions, such as pore water salinity change, depositional process alternation, wave loading, etc. The complicated behavior of marine clay is mainly attributed to its initial microscopic structure (fabric) and the evolution of its structure upon chemical, thermal, or mechanical disturbance. The microscopic structure has been found to be crucial to the development of a structure-informed constitutive model of marine clay [3]. The pore electrolyte–clay interaction and its effects on the fabric and macroscopic behavior of marine clay have been under investigation for decades. Salinity content can increase shear modulus and alter the damping ratio of marine clay, imposing an influence on the site response under seismic loading [4]

Methods

Results

Conclusion