(1. Institute of Mining Technology，Taiyuan University of Technology，Taiyuan，Shanxi 030024，China；2. College of Mining Engineering，China University of Mining and Technology，Xuzhou，Jiangsu 221008，China；3. College of Mining Engineering，Taiyuan University of Technology，Taiyuan，Shanxi 030024，China)
Abstract：Drilling issue will happen in high temperature and high pressure environment in the course of geothermal exploitation. The research on the cutting and breaking laws of rock is of great importance to improve the heat of the earth interior borehole efficiency under conditions of different temperatures and confining pressures. In order to gain the experimental effect most approaching the actual project，this experiment utilizes the “20 MN servo-controlled triaxial rock testing machine with high temperature and pressure”and designs precise pressure-adding and revolving system，leading to simple operational control and accurate measurement results. This experiment also utilizes a large-size(f 200 mm×400 mm) granite sample to make experimental condition approach actual project condition，thus serving as a pioneer for such experiments. By studying the cutting and breaking law of granite under high temperature and high pressure，the following results can be drawn. (1) Under high pressure condition(100 MPa)，cutting property of granite increases gradually with the temperature rising；and beyond a certain drilling pressure，cutting speed increases obviously with the temperature rising. Under 755 N weight on bit(WOB) in the experiment，the cutting speed at 300 ℃ increases by 30% to 50% than that at room temperature. (2) Under high pressure conditions(100 MPa)，the unit rock-breaking energy consumption reduces obviously with increment of temperature. Under 755 N WOB，the unit rock-breaking energy consumption at 300 ℃ reduces by 20% to 40% than that at room temperature. (3) In the high temperature and high pressure environments，the cutting speed increases with the rotation speed or WOB. Unit rock-breaking energy consumption increases with the rotation speed increasing，but reduces with WOB increasing. This pattern is basically consistent with that under room temperature without confining pressure. (4) Since granite is damaged gradually within this temperature and pressure range，and the compressive strength goes down slowly. If WOB is very slow，the temperature will have a very small effect on cutting rate and unit rock-breaking energy consumption. WOB needs to exceed a certain value in order to have a good granite cutting effect under high temperature environment. Further study can be conducted in this subject.
赵金昌，万志军，李义，赵阳升，董付科，冯子军，李根威. 高温高压条件下花岗岩切削破碎试验研究[J]. 岩石力学与工程学报, 2009, 28(07): 1432-1438.
ZHAO Jinchang1，WAN Zhijun2，LI Yi3，ZHAO Yangsheng1，DONG Fuke2，FENG Zijun2，LI Genwei2. RESEARCH ON GRANITE CUTTING AND BREAKING TEST UNDER CONDITIONS OF HIGH TEMPERATURE AND HIGH PRESSURE. , 2009, 28(07): 1432-1438.
