NUMERICAL MODELLING OF SURFACE SUBSIDENCE INDUCED BY UNDERGROUND PHOSPHATE MINES AT ABU-TATUR AREA.

Abstract

Different methods have been adopted to predict and quantify the subsidence by the subsidence parameters. These methods can be classified into three categories as follows:-1) Empirical methods based on the analysis of the field measurement, 2) Mathematical theories, 3) Numerical models including Finite Elements, Boundary Elements, and Distinct Elements methods. In this paper, the vertical component of subsidence is measured over working longwall panel at Abu-Tartur phosphate mines along transversal profiles at different face advancing rates. Finite element method (FEM) is applied to predict the subsidence trough over the excavated panel at different face advancing rates using three dimensional finite element program (Ansys package). The obtained results are compared with the measured ones. It was found that FEM results for surface subsidence coincide well with the measured data with a reasonable accuracy (correlation coefficient higher than 0.98). The degree of ground surface tilt, surface curvature and strain are obtained also by FEM model.