Experimental Study on Thermal Damage and Energy Evolution of Sandstone after High Temperature Treatment

Abstract EN

Thermal damage and energy evolution characteristics in process of impact failure of sandstone after high temperature treatment were studied by split Hopkinson pressure bar (SHPB) system.

The ultrasonic P-wave velocity, density, porosity, peak stress, ET/E0, thermal damage, fracture, and energy evolution characteristics of sandstone with temperature during the experimental process were explored.

Results show that, with the increase of temperature, the ultrasonic P-wave velocity and density decrease, while the porosity increases.

It is found that the peak stress and ET/E0 decrease with the increase of temperature, and the decreasing trend is fitted with the simple cubic equation.

Above 600°C, dynamic peak stress and ET/E0 decrease rapidly.

The thermal damage of rock increases with the increase of temperature, which is in accordance with the logistic curve model.

The thresholds of damage strain energy release rate are 200°C and 800°C in this research.

Its total input strain energy decreases with the increase of processing temperature and decreases sharply when the temperature is over 600°C.

The variation of total input strain energy has small change at the range from 400°C to 600°C.