Hazard warning card Lower Saxony 1 : 50 000 - Subsoil sensitive to settling and lifting

Description

The hazard warning card Niedersachsen 1 : 50 000 - Settlement and uplift sensitive subsoil (ISHB50) ) is taken from the geological map 1 : 50 000 (GK50) and the Engineering Geological Map 1 : 50,000 (IGK50) derived, many years of regional experience and soil mechanical analysis are taken into account in the creation of the map. The map shows the spatial distribution of the different types of subsoil sensitive to sedimentation and elevation up to a depth of 2 m. Underlying layers cannot be derived from the GK50 and the IGK50. For this purpose, the drilling database of the LBEG can provide further information and data. Criteria and rules are used to assess the nature, composition, formation of the geological unit as well as its soil mechanical stiffness, strength and water sensitivity as a subsoil with regard to the susceptibility to settling and lifting. Geological units with similar properties are summarized. Areas with load-dependent settlements in the expectation range of well-load-bearing subsoil are designated accordingly. 1.) high susceptibility to settling, e.g. due to high organic content and/or liquid to soft consistency 2.) medium to large settling sensitivity due to very low stiffness (fluvial, brackish, marine sediments such as lead) 3.) low to medium susceptibility to settling due to low stiffness such as loess loam, auelehm (marine, brackish and fluvial sediments) 4.) low to large settling sensitivity and small to large settling differences due to varying stiffnesses 5.) low to medium settling/lifting sensitivity of clay and clay rocks due to shrinkage/sources (water content changes), lifting due to crystallization pressure (due to pyrite weathering/plaster formation) 6.) sensitive to elevation (increase in volume) when water enters by converting anhydrite into gypsum 7.) Sensitive to subsidence due to the solubility of gypsum upon water entry 8.) usual load-dependent settlements of well-carrying loose and solid rocks General information on settlements and elevations can be taken from the subsoil types and targeted project-related investigations can be planned. Uplifting phenomena have so far only been observed in a few cases, mostly as a result of the swelling properties of clays. Raising as a result of gypsum crystal growth in the weathering area of clay stones has only been observed in isolated cases. The IHSB50 cannot replace ground tests in accordance with DIN EN 1997-2:2010-10, DIN EN 1997-2/NA:2010-12 and DIN 4020:2010-12.

Resources

Name Format Description Link
0 https://nibis.lbeg.de/net3/public/ogc.ashx?NodeId=991&Service=WMS&Request=GetCapabilities&

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