Soil and rock class

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In the construction industry, soils are divided into a total of seven soil and rock classes (often referred to as soil classes for simplicity ) according to their solvability and the technical properties . They are the basis for the selection of suitable foundation , rock and earthwork methods and for the calculation of the construction costs. The soil class is determined by experts from geotechnics or engineering geology .

Subdivision into soil and rock classes

Logo of the German Institute for Standardization DIN 18300
Area Construction
title VOB procurement and contract regulations for construction works - Part C: General technical contract conditions for construction works (ATV) - earthworks
Latest edition 2019-09
ISO -

The classification of the soil classes is carried out according to DIN 18300 VOB / C "earthworks" or according to ÖNORM B2205 "earthworks contract standard":

  • Soil class 1 : topsoil (topsoil); top soil layer, which contains not only inorganic substances but also humus and soil organisms .
  • Soil class 2 : Flowing soil types (scooped soil) from a liquid to viscous nature that give off the water with difficulty.
  • Soil class 3 : Easily detachable soil types; Non-cohesive to weakly cohesive sands , gravel and sand-gravel mixtures with up to 15 percent by weight admixtures of silt and clay and with a maximum of 30 percent by weight stones over 63 mm grain size and up to 0.01 m³ volume, organic soil types with better than pasty ones Consistency and peat .
  • Soil class 4 : soils that are moderately difficult to remove; Mixtures of sand and gravel with a proportion of more than 15% by weight of silt and clay, as well as cohesive soil types with light to medium plasticity and a maximum of 30% by weight stones with a grain size of over 63 mm up to 0.01 m³ volume.
  • Soil class 5 : Soil types that are difficult to remove; Soil types according to soil classes 3 and 4, but with more than 30% by weight stones with a grain size of over 63 mm and a volume of up to 0.01 m³; also non-cohesive and cohesive types of soil with a maximum of 30% by weight stones with a volume of more than 0.01 m³ to 0.1 m³ as well as pronounced plastic clays, which are soft to firm depending on the water content.
  • Soil class 6 : Rock types that have an internal, mineral-bound cohesion, but are strongly fissured, brittle, crumbly, schisty, soft or weathered, as well as comparable solidified, cohesive and non-cohesive soil types, such as those found in B. caused by drying out, freezing or chemical bonds; Non-cohesive and cohesive soil types with more than 30% by weight stones with a volume of over 0.01 m³ to 0.1 m³.
  • Soil class 7 : Rock that is difficult to remove; Rock types that have an internal, minerally bound cohesion and high structural strength and that are only slightly fissured or weathered; rock-bedded, unweathered clay slate, layers of nails, slag heaps from smelting works and the like.

After dividing the soil or rock into the respective soil class, the choice and use of equipment and construction machinery for loosening, transporting and compacting soil and rock is determined. The soil class also determines the maximum angle an embankment may have, up to which no further measures to secure the excavation are necessary. If the planned slope angle is steeper than the soil class itself allows (e.g. in building pits with limited space), construction measures are required so that the slope to be prepared does not collapse during the construction period.

In the case of soils whose cohesion can deteriorate due to frost, drying out, water penetration or the formation of sliding surfaces, it should be noted that the slopes must be even flatter than specified for soil classes 3 to 7, or stepped slopes, so-called berms are to be produced.

Division into homogeneous areas

The above-mentioned classifications are taken from VOB / C DIN 18300 edition 2012-09. With the edition of the VOB supplementary volume 2015 with DIN 18300 edition 2015-08 a fundamental change takes place.

In future, soil and rock will be divided into so-called homogeneous areas.

For the homogeneous areas, stipulated properties and parameters as well as their determined bandwidth must be specified, e.g. B. for floor:

  • customary local name
  • Grain size distribution with grain bands
  • Mass fraction of stones, blocks and large blocks
  • density
  • undrained shear strength
  • Water content
  • plasticity
  • Consistency number
  • Storage density
  • organic part
  • Floor groups according to DIN 18196

Source:

See also

literature

  • Wolfgang R. Dachroth: Handbook of building geology . 3rd expanded and revised edition, Springer Verlag Berlin Heidelberg, Berlin Heidelberg 2002, ISBN 978-3-642-62537-4 .
  • Bastian Fuchs, Hans-Gerd Haugwitz: Homogeneous areas. 2nd extended edition, Fraunhofer IRB Verlag, Cologne 2017, ISBN 978-3-8462-0814-4 .

Individual evidence

  1. ^ Ingo Grün, Wolfgang Grün: Construction paperback for judges and lawyers. Springer Fachmedien, Wiesbaden 1978, ISBN 978-3-528-08874-3 , pp. 88-90.
  2. ↑ Properties of soils (accessed January 12, 2018)
  3. ↑ H. -J. Bargstädt, R. Steinmetzger: Basics of the construction management. Bauhaus-Universität Weimar, Weimar Online pp. 20–26.
  4. ↑ Setting up the construction site (accessed on January 12, 2018)
  5. ↑ Earthworks according to the new earthworks standard DIN 18300: 2015 with homogeneous areas instead of soil and rock classes ( memento of the original from January 12, 2018 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (accessed on January 12, 2018) @1@ 2Template: Webachiv / IABot / www.schotterwerk-geiger.de
  6. ↑ Standardization of the soil and rock classes in the VOB / Part C standards in homogeneous areas (accessed on January 12, 2018)

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