When operating working at high amplitudes of the seasonal variations in air temperature and exploiting large-scale concrete construction, under conditions of temperature exchange with the surrounding rock mass, in mine aeration at great depths of the North deposit development, etc. recording of temperature influence on the stress strain state of the rock mass is required. Problems on the stress strain state of the rock mass exposed to the thermal influence are solved by method of boundary singular integral equations. To describe processes under conditions of nonstationary temperature exchange, temperature field dynamics is considered. When solving the problem in the plane statement, questions of formulating the boundary conditions are examined. Results are cited for the applied problem solution, in particular, stress strain state is studied in the vicinity of the working, located in the pit edge. The problem was solved for the ponderable half-plane. It is shown that in the specific cases, applied problem solution allows to obtain qualitative and quantitative estimation of temperature stress influence on the stress strain state of the rock mass.
During mining of deposits at the great depths or under conditions of the North air temperature at the surface and in the workings can be considerably different from the initial temperature of the massif. Difference in temperature leads to heat exchange and variation in temperature of the rock mass around workings.
To describe processes running under conditions of nonstationary heat exchange, it is necessary to consider temperature field dynamics with the use of the equation of nonstationary heat exchange.
(Equation in full paper)
SSS of the ventilated working symmetrical relative to the vertical axis was investigated (Fig. I). For the air temperature, linear dependence on time is accepted within the range of 200 days with variation in temperature from -5 upto -30°. The following physical rock parameters (alevrolites) arc selected: elasticity modulus E = 4· 104 MPa; Poisson's ratio ν = 0.23; heat conductivity k = 1.74 W/(m. deg); temperature conductivity æ = 10−6 m2/s; linear thermal expansion α = 10−5 deg−1; heat evolution from the working walls to the air flow αp = 10W/(m2. deg). Initial rock temperature and T = -5° stress state in the intact mass σ∞x= σ∞y = -20 MPa, σ∞xy = 0. To determine temperature field after 200 days of ventilation, a problem was solved with the step ∆t = 10 days. For the time moments t1 = 0 and t2 = 200 days, problem on SSS determination was solved. Figure I shows isolines of the temperature field t2 = 200 days. Temperature at the working contour is slightly different (for 2–3°) from the air temperature. Figure 2 demonstrates isolines of the middle pressure values in the vicinity of working at the moments t1(a) and t2 (b).