Creep-fatigue interaction of rock salt using discrete element simulation

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics Pub Date : 2024-09-25 DOI:10.1016/j.compgeo.2024.106771

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引用次数: 0

Abstract

The rock surrounding underground salt caverns hosting compressed air energy storage (CAES) systems is subjected to simultaneous creep and fatigue loads. A proper design considering the mechanical response and damage evolution of rock salt under such loading conditions is crucial for ensuring long-term stability. In addition to the conventional laboratory creep-fatigue tests, numerical simulation can serve as a complementary and validating method for unveiling the underlying mechanisms of interaction occurrences. The integration of these methods offers significant value in advancing our understanding of the meso-mechanical properties of rock salt. This study delves deep into the creep-fatigue interactions of rock salt using discrete element method (DEM) simulations. By establishing a DEM model of rock salt, that employs a hybrid contact model of Burger’s and linear parallel bond (LPB) to represent creep and damage behavior, respectively, we unveil the S-shaped evolution of the strain–time curve, encompassing initial, steady, stable damage, and acceleration deformation stages. Our findings highlight that stress intervals significantly reduce fatigue and creep life compared to pure creep and fatigue conditions. Furthermore, we demonstrate the effectiveness of a bilinear cumulative damage rule in describing the creep-fatigue life of rock salt under uniaxial conditions, with longer stress intervals leading to increased cumulative crack numbers and earlier crack initiation times. Ultimately, our numerical salt model exhibits an inclined shear crack and numerous micro-cracks surrounding the macro-shear crack, aligning with fracture modes observed in laboratory tests and advancing our understanding of rock salt behavior in CAES system.

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利用离散元模拟岩盐的蠕变-疲劳相互作用

承载压缩空气储能（CAES）系统的地下盐洞周围的岩石同时受到蠕变和疲劳载荷的作用。考虑到岩盐在这种载荷条件下的机械响应和损伤演变，正确的设计对于确保长期稳定性至关重要。除了传统的实验室蠕变-疲劳试验外，数值模拟也可作为一种补充和验证方法，用于揭示相互作用发生的内在机制。这些方法的整合为推进我们对岩盐介观力学特性的理解提供了重要价值。本研究利用离散元素法（DEM）模拟深入研究岩盐的蠕变-疲劳相互作用。通过建立岩盐的 DEM 模型（该模型采用伯格和线性平行键（LPB）混合接触模型分别表示蠕变和损伤行为），我们揭示了应变-时间曲线的 S 型演变，包括初始、稳定、稳定损伤和加速变形阶段。我们的研究结果表明，与纯蠕变和疲劳条件相比，应力间隔会显著降低疲劳和蠕变寿命。此外，我们还证明了双线性累积损伤规则在描述单轴条件下岩盐蠕变-疲劳寿命方面的有效性，应力间隔越长，累积裂纹数越多，裂纹萌发时间越早。最终，我们的岩盐数值模型显示出倾斜剪切裂纹和围绕宏观剪切裂纹的大量微裂纹，这与实验室测试中观察到的断裂模式一致，加深了我们对 CAES 系统中岩盐行为的理解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Computers and Geotechnics 地学-地球科学综合

CiteScore

9.10

自引率

15.10%

发文量

438

审稿时长

45 days

期刊介绍： The use of computers is firmly established in geotechnical engineering and continues to grow rapidly in both engineering practice and academe. The development of advanced numerical techniques and constitutive modeling, in conjunction with rapid developments in computer hardware, enables problems to be tackled that were unthinkable even a few years ago. Computers and Geotechnics provides an up-to-date reference for engineers and researchers engaged in computer aided analysis and research in geotechnical engineering. The journal is intended for an expeditious dissemination of advanced computer applications across a broad range of geotechnical topics. Contributions on advances in numerical algorithms, computer implementation of new constitutive models and probabilistic methods are especially encouraged.