Study on stability evaluation scheme of old goaf in closed mine
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Abstract
In order to analyze the stability of the old goaf in a closed mine, through the detailed investigation of the current situation of the mine goaf, the characteristics of the goaf state are clarified, and the qualitative analysis and numerical simulation methods are used to evaluate. The results show that the goaf above the middle section of −250 m has been formed for more than 20 years. The overburden is thick, complete, strong and has no cracking and sinking on the surface. It is in a stable state. After the formation of the middle goaf below −250 m, the stress concentration in the local area occurs, and the maximum tensile stress is about 1.5 MPa, which does not exceed the tensile strength of the rock layer. The maximum vertical displacement occurs in the roof position, the overall displacement deformation is small, the sinking and floor heave phenomenon is not obvious. After the surface is covered with soil, the stress and displacement of the goaf are almost unchanged. By the comprehensive analysis, underground goaf can remain stable. The research results are expected to provide a technical route for the analysis of the stability of the old goaf.
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