Pan Yize, Gong Xiaohui, Rotta Loria Alessandro F
Department of Civil and Environmental Engineering, Subsurface Opportunities and Innovations Laboratory, Northwestern University, Evanston, USA.
Sci Rep. 2024 Mar 21;14(1):6828. doi: 10.1038/s41598-024-57503-2.
Granular materials with irregular particle shapes undergo a myriad of temperature variations in natural and engineered systems. However, the impacts of cyclic temperature variations on the mechanics of granular materials remain poorly understood. Specifically, little is known about the response of granular materials to cyclic temperature variations as a function of the following central variables: particle shape, applied stress level, relative density, and temperature amplitude. This paper presents advanced laboratory experiments to explore the impacts of cyclic temperature variations on the mechanics of granular materials, with a focus on sands. The results show that cyclic temperature variations applied to sands induce thermal shakedown: the accumulation of irreversible bulk deformations due to microstructural rearrangements caused by thermal expansions and contractions of the constituting particles. The deformation of sands caused by thermal shakedown strongly depends on particle shape, stress level, relative density, and temperature amplitude. This deformation is limited for individual thermal cycles but accumulates and becomes significant for multiple thermal cycles, leading to substantial compaction in sands and other granular materials, which can affect various natural and engineered systems.
在自然和工程系统中，具有不规则颗粒形状的粒状材料会经历无数次温度变化。然而，循环温度变化对粒状材料力学性能的影响仍知之甚少。具体而言，关于粒状材料对循环温度变化的响应作为以下核心变量的函数，人们了解甚少：颗粒形状、施加的应力水平、相对密度和温度幅度。本文介绍了先进的实验室实验，以探索循环温度变化对粒状材料力学性能的影响，重点是沙子。结果表明，施加在沙子上的循环温度变化会引起热安定性：由于构成颗粒的热膨胀和收缩引起的微观结构重排导致不可逆的整体变形的积累。热安定性引起的沙子变形强烈取决于颗粒形状、应力水平、相对密度和温度幅度。这种变形在单个热循环中是有限的，但会积累并在多个热循环中变得显著，导致沙子和其他粒状材料发生大量压实，这可能会影响各种自然和工程系统。
