Key Takeaways & Executive Findings
- •• Developed a novel multi-scale cross-platform PFC-FDEM coupling methodology for simulating thermal-mechanical rock behavior. • Identified three-stage crack evolution with temperature-dependent density following an exponential model. • High-temperature exposure reduces dynamic strength ratio by 60% at 800°C and diminishes strain-rate sensitivity. • Numerical predictions show excellent agreement with experiments (±8% peak stress-strain errors).
Abstract
Underground engineering in extreme environments necessitates understanding rock mechanical behavior under coupled high-temperature and dynamic loading conditions. This study presents an innovative multi-scale cross-platform PFC-FDEM coupling methodology that bridges microscopic thermal damage mechanisms with macroscopic dynamic fracture responses. The breakthrough coupling framework introduces: (1) bidirectional information transfer protocols enabling seamless integration between PFC’s particle-scale thermal damage characterization and FDEM’s continuum-scale fracture propagation, (2) multi-physics mapping algorithms that preserve crack network geometric invariants during scale transitions, and (3) cross-platform cohesive zone implementations for accurate SHTB dynamic loading simulation. The coupled approach reveals distinct three-stage crack evolution characteristics with temperature-dependent density following an exponential model. High-temperature exposure significantly reduces dynamic strength ratio (60% at 800 °C) and diminishes strain-rate sensitivity, with dynamic increase factor decreasing from 1.0 to 2.2 (25 °C) to 1.0–1.3 (800 °C). Critically, the coupling methodology captures fundamental energy redistribution mechanisms: thermal crack networks alter elastic energy proportion from 75% to 35% while increasing fracture energy from 5% to 30%. Numerical predictions demonstrate excellent experimental agreement (±8% peak stress–strain errors), validating the PFC-FDEM coupling accuracy. This integrated framework provides essential computational tools for predicting complex thermal–mechanical rock behavior in underground engineering applications.
1. Introduction
Geological formations within terrestrial lithospheric architectures exhibit complex mechanical behaviors under extreme thermal regimes and dynamic loading conditions that critically influence deep subsurface engineering applications including geothermal energy extraction systems and deep geological nuclear waste sequestration strategies. Substantial research efforts have characterized rock property evolution under thermal influence and dynamic mechanical response. However, the intricate multi-scale coupling mechanisms governing progressive degradation dynamics under synergistic thermomechanical loading regimes remain challenging to characterize, representing an important area requiring further theoretical and methodological development in geomechanical research.
Contemporary multi-scale computational methodologies for rock mass analysis are predominantly categorized into three principal taxonomic frameworks: continuum-based hierarchical homogenization paradigms, hybrid discrete-continuum algorithmic architectures, and heterogeneous computational platform integration strategies. Continuum-based homogenization approaches achieve scale-bridging through microscopic representative volume elements (RVEs) at macroscopic Gauss quadrature points. Asymptotic finite element homogenization (FE2) and variational multi-scale formulations demonstrate exceptional efficacy for materials with periodic microstructural architectures, as pioneered by Matous et al. These methodologies have established...
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Yue Zhai, Shaoxu Hao, Shi Liu, Yu Jia (2025). PFC-FDEM multi-scale cross-platform numerical simulation of thermal crack network evolution and SHTB dynamic mechanical response of rocks. SinoTechIntel Verified Research. https://doi.org/10.1016/j.ijmst.2025.08.013
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Frequently Asked Questions
What is the PFC-FDEM coupling method?
It is a multi-scale cross-platform numerical simulation approach that integrates Particle Flow Code (PFC) for microscopic thermal damage characterization and Finite-Discrete Element Method (FDEM) for continuum-scale fracture propagation, enabling accurate simulation of thermal-mechanical rock behavior.
How does high temperature affect rock dynamic strength?
High-temperature exposure significantly reduces the dynamic strength ratio, with a 60% reduction at 800°C, and diminishes strain-rate sensitivity, as indicated by the dynamic increase factor decreasing from 1.0–2.2 at 25°C to 1.0–1.3 at 800°C.
What are the key findings on crack evolution?
The study reveals distinct three-stage crack evolution characteristics with temperature-dependent density following an exponential model, capturing the progressive degradation of rock under thermal loading.
How accurate are the numerical predictions?
Numerical predictions demonstrate excellent agreement with experimental results, with peak stress-strain errors within ±8%, validating the accuracy of the PFC-FDEM coupling methodology.
What are the applications of this research?
This integrated framework provides essential computational tools for predicting complex thermal-mechanical rock behavior in underground engineering applications such as geothermal energy extraction and deep geological nuclear waste sequestration.
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