SIMULATION AND OPTIMIZATION FOR THERMAL SYSTEM IN GROUND ARTIFICIAL FREEZING

The situation of mine development in coal industry of China and the method of shaft freezing in the type of double ring freezing pipe used for shaft sinking under thick alluvium condition are briefly reviewed. The equations of heat conduction are numerically solved for two kinds of artificial shaft freezing-sin-gle and double ring freezing pipe pattern. A two-dimensional finite difference model simulating the temperature field is developed. The paper introduces a way to calculate the harmonic mean of heat conductivety used when dealing with heterogeneous material, The theoretically derived temperature distributions in frozen soil are given and the comparison is made between two types of freezing pipe arrangement. The optimization technique of a general simulation is discussed, and that is in use to improve the thermal system in shaft freezing.