Study On The Freezing Temperature Field And The Stress Field Protecting The Ventilating Shaft Walls In Tashidian

In recent years, the construction of the mines in western China has been in full swing. Many mineshaft flooding accidents happened in the western mines which were built with the common methods. After the accidents, the freezing methods were mostly adopted to complete the rest of the construction of the mines. During the process of using the freezing methods to deal with the accident shafts, we face many problems of the key engineering technologies. The paper takes protection issues of the established side wall of No.1 mining air shaft, which is constructed with freezing method in Tashidian mining lot as mainline, adopts the method of combining theoretical analysis, numerical simulation and field measurement and focuses on research into such aspects as mechanical property experiment of frozen earth, evolution laws of freezing temperature field under temperature control, distribution of frozen stress field and numerical inversion based on project field measurement.In view of the mine shaft inspection hole coring samples, frozen soil physical and mechanical tests have been carried out. Experimental results show that the uniaxial compressive strength of the rock in the low temperature is low, less than 10 MPa. Creep test sample is unsteady creep. Temperature, stress and time are the key factors influencing the frozen soil creep. Sample in the case of no water supply have certain frost heave.According to the thermodynamic parameters of frozen soil test, freezing temperature field model is established under the condition of temperature control by ANSYS software, analyzing freezing temperature field finite element. Results show that the thermostat hole open after freezing temperature field in frozen pipe centered in concentric circles development trend, temperature isothermal inner concave shape near the tube. Frozen in the temperature control in the primary side characteristic curve mutations affect the development of frozen wall. Adopting the method of indirect coupling thermal stress analysis, frozen stress distribution is got. Display in the frozen wall accumulating frost heaving force. The area of thermostat holegets the effect of the stress of the buffer.Contrast the characteristic parameters of freezing temperature field and stress field of within open and without open hole temperature, thermostat hole set to engineering practical significance, providing a reference for borehole wall protection.Finally, the stratigraphic simulation mode is got by numerical inversion based on the measured data. Using the thermostat hole from the model the optimal timing of opening 70 ds and the optimal temperature from 10 ℃ to 15 ℃ guiding the project construction. The effect of engineering construction is excellent. At the same time, it verifies the reliability and significanceof the simulation results.