Abstract
To reveal the mechanical behavior mechanism of collapse and to control risks effectively, the instability extent of the collapse area was established through theoretical mechanics and numerical methods, taking one metal mine as a case study; on this basis, a routine reinforcement program was determined, and the effect of the program was evaluated. The results show the following. (1) Analytical formulas of the critical slip angle and the collapse height of the ore body were derived by the mechanics method, and the rock mechanics parameters were obtained by field coring and physical and mechanical experiments. The slipping line angle increases along with uniform force Q and is inversely proportional to the bending stiffness. Meanwhile, the calculation formula for the maximum subsidence of ore body was deduced. (2) Numerical results can be used to determine the basic form of the collapse area, and a “U-shaped” collapse area formed when a plastic area passed completely through, resulting in the overall destruction. (3) The grouting reinforcement program includes “determining the instability region ⟶ roadway temporary support ⟶ improve the water environment and surrounding rock bearing capacity ⟶ mining planning” which were determined on the basis of prediction. (4) The hierarchical structure of the rock body and filling were improved combined with the Delphi method, and the grouting effect evaluation model was constructed and verified using the improved FD-AHP method; the evaluation value indicating that the grouting reinforcement improved the bearing capacity of ore body and filling body in collapse area. The research results provide systematic reference and technical support for the analysis of stope collapse mechanism, prediction of hidden trouble, and the subsequent mining.
Highlights
(1) Analytical formulas of the critical slip angle and the collapse height of the ore body were derived by the mechanics method, and the rock mechanics parameters were obtained by field coring and physical and mechanical experiments. e slipping line angle increases along with uniform force Q and is inversely proportional to the bending stiffness
Mining safety is an important part of the public safety, and reasonable and effective use of mineral resources is the responsibility of the whole society [1]
Grig studied the mechanical behaviors of iron ore and marl based on rock mechanics tests with FLAC 2D software [13]
Summary
Mining safety is an important part of the public safety, and reasonable and effective use of mineral resources is the responsibility of the whole society [1]. Prediction of the slip boundary and its influence [5] along with the deformation and subsidence of ore body (filling body) [6] will affect the further exploitation of hidden resources directly. Yao [10], followed by Wood [11], employed the finite element method and the boundary element method to study the conditions and heights of overlying rock collapse caused by stoping. Erefore, to improve mining safety and reveal the mechanical behavior mechanism of collapse and control risks, combined with a metal ore mine as a case study, in view of the complex mining conditions of the collapsed area, the theoretical mechanics and numerical analysis model are built to calculate the influence extent of collapse area through field coring and laboratory physical and mechanical experiments. Engineering background of the metal mine is as follows. e range of vertical collapse is from elevation −298.3 m to −232.0 m, north-south coordinates from 290.5 to 420.0 (Figure 1), with the width of each stope of approximately 6.5∼8 m. e mining has been finished and filled (the remaining stakes are interpillar stope), and the second half of the 0# stope is approximately 22.5 m high. e collapse of the goaf caused the filling of two sides into the goaf and the upper ore body subsidence
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
