Surface Subsidence Prediction Over Working Longwall Panel at Abu-Tartur Phosphate Mines

Abstract

The phenomenon of subsidence is the movement at the ground surface caused by underground excavations, which can cause severe damage to buildings or structures on the surface and infrastructure. These excavations exert redistribution of the original stresses around the openings. Different methods have been adopted to predict and quantify the subsidence with the subsidence parameters. These methods can be classified into three categories 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 surface subsidence data were collected over working longwall panel at Abu-Tartur phosphate mines after the face had been advanced 280m. Different mathematical theories namely Bals', Peng's, Knothe's and Peck's theories are applied to predict the subsidence trough over the excavated panel. The obtained results are compared with the measured ones. It was found that Peck's theory coincides well with the measured data. The degree of ground surface tilt, surface curvature and strain are derived from Peck's theory.

Settlement Behavior of Road Surfaces Caused by Dissolution of Salt Layers

“…In so doing, they compared the true measurement parameters against the steepness, curve, and plasticity. The method proposed by Peck yielded the parameters closest to the reality, with the coefficient accuracy over 0.9 [7].…”

“…Soil surface settlement is caused by 3 factors, namely: 1) cracks, splits, or different degrees of cracks, 2) sinkholes or holes, 3) water puddles or soil depressions [6]. Elashiry et al (2008) conducted a study of surface soil settlement of a phosphate mine by comparing the efficiency of the settlement equations proposed by Bal, Peng, Knothe, and Peck. In so doing, they compared the true measurement parameters against the steepness, curve, and plasticity.…”