坑道周辺岩盤中の温度分布および岩盤から放散される熱量について

坑内通気温度計算への差分法の応用 (第2報)

抄録

In order to predict the temperature of ventilation air in mines it is essential to calculate accurately the temperature distribution in rocks around a roadway and the heat flow into the air current. Many authors have considered the problem of unsteady heat conduction., However, in previous studies many assumptions were made to simplify the problem, and some of the assumptions have never been discussed quantitatively. Consequently, there are uncertainties about the validity of these assumptions.
In this point of view, the authors examined the following assumptions by means of finite difference method, forcusing on the problem in coal mines;
(a) circular roadway
(b) isotropic rock, and
(c) homogeneous rock.
Examination of these assumptions leads to the following conclusions;
(a) To a good approximation the total heat flow is the same as that for a circular roadway having the hydraulic diameter of the actual roadway.
(b) The anisotropy of coals and shales are not negligible. However, a good approximation is obtained by calculating the heat flow for a roadway driven in isotropic rock whose thermal conductivity is the geometric mean of the thermal conductivities parallel and vertical to the bedding plane.
(c) When a roadway is driven into the coal seam, the coal seam has a great effect upon the temperature distribution in rocks and the total heat flow. In the present paper a method is proposed for modifying the equation for prediction of air current temperature to take into consideration the effect of the coal seam.