Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
Geological environment and its engineering geological characteristics on the 13-143 Pečky map sheet
AbstractNearly the whole surveyed area is part of the Nymburk basin with the Labe river accumulation sequence. A complex of sandy, silty and argillaceous sediments of late Cretaceous age predominates in the pre-Quarternary bedrock. Only SW corner of the map sheet is covered by migmatites of the Kutná Hora crystalline complex. The most-represented Quarternary sediments are the terrace deposits of Günz 1-Würm age, covered by loess deposits at higher levels. The youngest and most widespread terrace level (Würm) is to a considerable degree covered by eolian sands that form locally sand dunes (Sokoleč, NW of Oseček, Písková Lhota). Foundation soils with the highest bearing capacity lie on migmatites (Rdt = 175-275 kPa - at a base width of 1 m). Foundation engineering on the Cretaceous marls is largely hampered by their high degree of weathering. Eluvia reach down to a depth of 4 m and they have a lower bearing capacity (Rdt = 80-100 kPa). Their properties are shown in Figs. 1, 2 and 3. Terrace deposits form a good foundation soil and they consist of sands (fraction 0.25-2.0 mm) predominating over gravels (fraction 2-32 mm) - Fig. 4. In higher terraces the groundwater level is deeply sunken, being situated only in a depth of 2-3 m in the Würm terrace.