SUBSTANTIATION OF TECHNOLOGICAL PARAMETERS OF THERMAL CONTROL OF THE FROZEN WALL

Abstract

The relevance of the study is caused by the lack of regulatory documents for the control of the rock mass in the conditions of its artificial freezing, unified requirements for organization and monitoring of the frozen wall formation. The main aim of the work is to substantiate the optimal technological parameters of the thermal control of the frozen wall. Objects of the research are the rock mass under the conditions of artificial freezing and the freezing system. Methods: experimental study of the temperature dynamics of the frozen rocks, statistical processing and analysis of experimental data; simulation of thermodynamic processes occurring in artificially frozen rock mass. Results. The paper presents the experimental measurements of temperature distribution in control wells in artificially frozen rock mass. The artificial freezing is considered in relation to the problem of mine shaft sinking in flooded rocks. Processing and analysis of experimental data shown the influence of the artificial freezing on local sections of the rock mass. A study was made of the influence of the control well location on the accuracy of the solution of the inverse Stefan problem. It makes possible to adjust the thermophysical properties of the rock mass model and calculate the temperature field in the entire volume of the frozen rock mass. It was determined that the control well should be placed straight between the adjacent freezing wells. The analysis of the emergency failures of the freezing wells showed that the required number of control wells should be at least 30 % of the total number of freezing wells. Performed thermal monitoring allows the substantiation of optimal locations and number of control wells with the necessary spatial resolution of temperature measurements of rock mass in depth. According to the results of the work, a methodology for selecting technological parameters of the method of frozen wall thermal control were proposed.

Keywords

• frozen wall
• mine shaft
• thermal control
• technological parameters
• thermal control well
• temperature measurements
• freezing well
• stefan problem