The Geology of coal in the Netherlands III - Conventional deep mining research - Rock support by a destressed ring of rock around a gallery under severe stress

Abstract

The aim of the project is to control the fracturing process of rock surrounding underground galleries under severe stress conditions. Model experiments indicate that a considerable decrease of convergence of galleries will occur if a circular zone of rock with a certain width around the gallery is artificially weakened and destressed. An underground field test confirmed that a destressed tubular rockmass around the excavation could support serious stress deviations of the surrounding bedrock, so that the gallery remained practically undamaged. It is expected that procedures following the lines of the described tests will improve the economy and the extent of deep coal mining