Heating Technique For High Temperatures Pressure Impact Of Rock

Many engineering fields are all involved in high-temperature dynamic mechanical properties of rock, such as storage of nuclear waste, exploitation of mineral resources, construction in mining area and underground construction, etc. Thus exploring the testing method of dynamic fracture toughness of rock under the high temperatures has very important significance. However, the technologies in the rock heating process of the high-temperature dynamic mechanical properties tests are currently far from maturity at home and abroad. So developing the rock heating technologies of high strain rate tests is very urgent.In this paper, design a furnace to heat the rock specimen of Central Cracked Circular Disk for the impact compression test on split Hopkinson pressure bar (SHPB) device. The furnace is mainly composed of entocoel paries, shells, insulation layers and heating components, adopting the technology of slowly heating with resistive wires. Through the rational design of cavity structure and shape, it not only meets the requirements of the using with an improved SHPB device, but also achieving goals heating the specimen with uniform temperature field.This paper describes using furnace heating system with two kinds of heating methods. One is heating specimen when separating the specimen from pressure bars, the other is heating specimen under contacting specimen with the bars. Then, through numerical simulation and measurement, the temperature fields of two kinds of heating methods have been attained. The results show that the temperature field with the heating method of noncontact heating more uniform than contiguous heating, but the average temperature of specimen is lower. At the same time, the corresponding relationships between the specimen temperature, the furnace chamber temperature and power temperature have been established under two kinds of heating methods, by analyzing the results, then find that there is a good linear correlation between the temperature of the furnace entocoel and the specimen. During high-temperature impact compression experiment, we can determine the furnace entocoel the temperature and power temperature basing on the specimen temperature by the Correspondence. Simultaneously, the results of temperature test show that when the furnace chamber temperature is up to 300℃, the point where the strain gages paste is at room temperature, and its effectiveness of measurement almost has no effect. The above work provides reliable testing foundation for the high-temperature dynamic study on the characteristics of rock.