Geotechnical characteristics of unburnt colliery spoils after coal-recovery

Abstract

The aim of the study was to determine the geotechnical characteristics of the unburnt colliery spoils after coal-recovery from the dumping site of one of the mines of the Upper Silesian Coal Basin in Poland. Due to grain-size distribution of tested spoils their geotechnical properties were determined using medium-sized apparatuses. In order to verify the suitability of the studied spoils for the construction of hydraulic embankments, the seepage and stability calculations were conducted for models of hydraulic embankments including the effect of flood wave passage on stress conditions within the construction and their slope stability. The test results revealed, that the studied colliery spoils are characterized by favourable values of geotechnical parameters and they fulfil the requirements for soil materials used in the analysed type of constructions. The spoils are characterized by good compactibility, relatively low water permeability and average susceptibility to mechanical disintegration, which in the case of using this material for the construction of hydraulic embankments and using proper compaction technology, should reduce their susceptibility to weathering. The results of seepage and slope stability calculations for hydraulic embankments built of the studied spoils confirmed their suitability for that type of constructions, retaining the proper inclination of slopes, whereas the variant of embankment without sealing is safer from the stability viewpoint.