Effect of particle shape on creep behavior of calcareous sand and the underlying mechanism--颗粒学报PARTICUOLOGY

Sun, L., Gao, Y., Yuan, Q., Wang, Y., & Tang, X. (2026). Effect of particle shape on creep behavior of calcareous sand and the underlying mechanism. Particuology, 108, 1-13. https://doi.org/10.1016/j.partic.2025.11.003

Effect of particle shape on creep behavior of calcareous sand and the underlying mechanism

Le Sun^a, Yan Gao^{a b *}, Quan Yuan^c, Yanlun Wang^a, Xudong Tang^a

a School of Earth Sciences and Engineering, Sun Yat-sen University, Zhuhai, 519080, China
b Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, China
c Guangzhou Metro Design and Research Institute CO., LTD., Guangzhou, 510010, China

10.1016/j.partic.2025.11.003

Volume 108, January 2026, Pages 1-13

Received 25 September 2025, Revised 6 November 2025, Accepted 9 November 2025, Available online 14 November 2025, Version of Record 3 December 2025.

E-mail: gaoyan25@mail.sysu.edu.cn

Highlights

• Particle shape is the key factor controlling calcareous sand creep behavior.

• Lump-shaped sand has the best creep resistance and longest structural effect.

• Unique breakage modes in dendritic and biogenic debris sand cause creep failure.

• Creep alters particle morphology, changing fractal dimension and aspect ratio.

• Particle morphology controls creep via breakage mode, degree, and structure.

Abstract

This study investigates the creep characteristics of calcareous sand with three realistic and typical particle shapes (lump, dendritic, and biogenic debris) under different deviatoric stress ratios through multistage loading triaxial creep tests. The particle breakage patterns and creep mechanisms of calcareous sands are revealed based on CT scanning. The results demonstrate that lump-shaped calcareous sand exhibits the smallest axial creep deformation, the longest duration of creep structural effect, and the latest occurrence of creep failure stage, manifesting as volumetric expansion. Dendritic calcareous sand shows intermediate axial creep deformation, significantly shortened creep structural effect duration, and slight volumetric contraction. Biogenic debris calcareous sand presents the largest axial creep deformation, the shortest creep structural effect duration, and considerable volumetric contraction. After creep, lump-shaped calcareous sand displays the least particle breakage, dominated by particle grinding and overall breakage modes; dendritic calcareous sand exhibits intermediate particle breakage, primarily through particle fracture; while biogenic debris calcareous sand suffers the most severe breakage, characterized by penetrating fractures and overall breakage modes. The shape characteristics of all three particle morphologies are significantly affected by creep. After creep, the fractal dimension and mean aspect ratio of both lump-shaped and biogenic debris calcareous sands increase, whereas those of dendritic calcareous sand decrease. Particle shape ultimately determines creep behavior differences by regulating force chain distribution, breakage modes, and breakage degree. This study elucidates the variations and control mechanisms in creep deformation among three particle shapes of calcareous sand, providing theoretical foundations for marine engineering design.

Graphical abstract

Keywords

Calcareous sand; Particle shape; Creep characteristics; Fracture mode; Meso-mechanism

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