# Thermomechanical Behavior and Mesoscale Simulation of Conglomerate under Impact Loading for Geothermal Engineering

## TL;DR

This paper studies how conglomerate rock behaves under high temperatures and impact, showing it becomes more brittle and less strong as temperature increases.

## Contribution

The novel contribution is the combined experimental and mesoscale simulation analysis of conglomerate under high-temperature impact loading.

## Key findings

- Dynamic compressive strength of conglomerate decreases by 39.5% as temperature increases from 25°C to 300°C.
- Higher temperatures lead to more brittle failure and finer fragmentation, as shown by fractal dimension analysis.
- Energy dissipation decreases at elevated temperatures, promoting brittle behavior and stress localization.

## Abstract

To investigate the mechanical response of conglomerate
under coupled
high-temperature and dynamic loading conditions, impact compression
tests were conducted using a ⌀50 mm Split Hopkinson Pressure
Bar (SHPB) system at temperatures of 25 °C, 100 °C, 150
°C, 200 °C, 250 °C, and 300 °C. At lower temperatures,
the specimens exhibit greater energy absorption and dissipation capacity,
which promotes crack propagation and energy release. In contrast,
at elevated temperatures, energy reflection becomes more pronounced
while dissipation decreases, leading to a more brittle failure mode.
Mesoscopic analysis based on finite element simulations further clarifies
the influence of temperature on stress distribution and crack evolution
during impact failure. The results indicate that the dynamic compressive
strength of conglomerate decreases with increasing temperature, with
the peak stress dropping from 192 MPa at 25 °C to 116 MPa at
300 °C, corresponding to a reduction of approximately 39.5%.
Fractal dimension analysis reveals a positive correlation between
fragmentation degree and temperature, with significantly finer fragments
observed at 300 °C compared to 25 °C. These findings provide
theoretical insights and practical guidance for evaluating the stability
of high-temperature conglomerate formations and optimizing rock-breaking
parameters in geothermal engineering.