| Since the1980s, the damages of more than100shafts in varying degrees have happened in the mining areas of east and northeast part of China, which cause serious security risk to mine production and economic losses. Based on the background of the second Dongrong Mining’s auxiliary shaft, in this paper a monitoring method for shaft is provided, which adopts FBG sensing technology, accordingly the matching monitoring and early warning system is developed, and the method of shaft safety state evaluation and early warning is studied. All of that will provide the reference to the similar project of shaft safety monitoring and early warning in future.This paper main research work is as follows:(1) The stress characteristics of the thick topsoil shaft are analyzed from the theoretical point of view. The loads on the shaft are classified and the calculation methods of the loads are given. The calculation formulas of the stress and the stress state of both inside and outside wall flange are deduced during the time of mine operation and the main factors of shaft damage are discovered. On this basis, shaft failure mechanism is analyzed and the rule of casing damage of shaft concrete is established.(2) This paper introduces the sensing principle of the FBG sensor and strain sensing properties. The strain transfer relationship between FBG and shaft wall is obtained by analysis. The principle of shaft monitoring and the monitoring parameters is confirmed. The methods of obtaining original data of shaft deformation and shaft evaluation and early warning are proposed.(3) Combining with the engineering practice of the second Dongrong Mining’s auxiliary shaft, design and develop the monitoring and early warning system, which realized the real-time for deformation monitoring of shaft wall and the function of the safety early warning target. The system is successfully applied to engineering practice and the running effect is evaluated. |
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