Geotechnical study of the requisite information on the workability of rocks and the Pre-Quaternary bedrock (Ostrava region)

At present, it is vital to take into account certain geological factors when planning the future development within the land-use planning. The case study attempts it concerns only the evaluation of two selected geofactors out of many, namely the workability of rocks and the Pre-Quaternary bedrock. It was implemented in the town quarters of the city of Ostrava making use of overlay analyses in the Geographic Information Systems in three time periods of the current built-up area, the state in 1946 and their inter-period to identify the trend of changes. The study area concerns five map sheets in a scale of 1:10 000. The workability of rocks is important in the projection activities for the reference identification of the amount of the necessary work to do the earthwork. The analysis of rock workability was proved that the dominant rock workability classes are 1 to 4 (97.4% – more suitable rock). The Pre-Quaternary bedrock is important especially in the design of demanding constructions as it is where structures are usually founded or, in other cases, when the Quaternary rocks have unsuitable geotechnical parameters. The Pre-Quaternary cover type analysis showed that the most wide-spread type in the study area is the type of alternation of cohesive and non-cohesive soils (90%), namely with the base depth within 5–10 m (45.8%) and over 10 m (26.1%).