Experimental of infrared thermal image in limestone drilling

Thermal effects have significant impacts to material properties and thermal injury of the rock during rock excavation. The measurement principle of infrared imaging temperature is introduced. Infrared-Charge Coupled Device (IR-CCD) was used to study the infrared thermal image of the rock during excavation process. The experimental results under certain conditions show that thermal-affected zone of the rock in drilling was similar to the shape of warhead, and the thickness of thermal-affected zone was roughly the same as radius of the drill bit. The average temperature of the thermal-affected zone reduces during the cooling process after drilling, but the area of the thermal-affected zone expands gradually. The rock temperature in drilling axes reduces and the position of the max temperature point on it is changing with the cooling time, the discrepancy between each other is also decreasing as time pass by. This process is influenced by drilling diameter, drilling depth, the thermal and mechanical properties etc. The decreasing speed of maximum temperature in the rock is faster in the beginning of the cooling process than it in the middle and the end of the process. Experimental results confirm that it is utility and effective to use IR-CCD in measuring and analysing the rock temperature in drilling. The conclusions provide important references to improve the efficiency and security of the drilling project.