Construction site

The construction site is to be evaluated, described and investigated in detail for the professional execution of construction projects.

Shoring of excavations with sheet pile walls
Shoring of excavations with sheet pile walls
© Reto Wagner, Kellerhals+Haefeli AG, Bern

Summary

In a civil engineering construction context, ground made up of unconsolidated or consolidated rock in the area of a building project or foundation is described as (construction or building) ground. According to DIN 4020, paragraph 3.1, “ground” is “soil or rock including all constituents (e.g., groundwater and contamination), in and upon which structures are to be based or embedded, or is to be influenced by construction activities”.

The characteristics of the ground are particularly important with respect to the foundation of a building. The bearing capacity is essential: the ability to absorb loads from the building without resulting in significant subsidence or foundation failure occurring.

The geotechnical site investigation: fundamentally important

The ground is composed of different soil or rock layers. Depending on the geological context, groundwater ingress can be expected. Modified construction measures are then required: the groundwater can for example be lowered by pumping.

The characteristics of the ground are primarily determined by the soil types and soil (rock) classes. As a function of the geological context, these characteristics can be very homogeneous. The initial site investigation for the geotechnical characterization of the soils and rocks therefore represents an important step in each construction project.

In Switzerland, the ground, ground investigation and corresponding ground classes are described in detail in the standards SIA 261, SIA 261/1, SIA 267 and SIA 267/1.

Who is who

Without ground no construction. – The major players for the topic ground at a glance.

Most geology bureaus carry out site investigations as part of their offering. A canton-specific list can be found in the address directory of the Swiss geosciences: Geoscience Switzerland.

Address directory of the Swiss geosciences: Geoscience Switzerland

For theoretical and research orientated aspects, the following institutes and commissions are important key contacts in connection with the topic ground:

Institute for Geotechnical Engineering of ETH Zürich
Wolfgang-Pauli-Str. 15
ETH Zürich, HIL C 13.2
CH-8093 Zürich

Tel. +41 44 633 25 25
E-Mail
Website (English)

The Institute for Geotechnical Engineering deals with soil and rock mechanics, clay minerals, geotechnical engineering and geo-environmental engineering. The institute is responsible for teaching and research, has highly specialized laboratories and field equipment at their disposal and offers various services. 

Engineering Geology of ETH Zürich
ETH Zürich
Geological Institute, Engineering Geology
Sonneggstrasse 5
CH-8092 Zürich

Tel. +41 44 632 36 65
Fax +41 44 632 10 80
Contact form
Website (English)

The group for Engineering Geology is part of the Geological Institute of ETH Zürich. It researches the hydraulic and mechanical processes in fractured rock masses. The studies do not remain mere pure research, but are implemented daily in the fields of tunneling, natural hazards, geothermal energy or the sustainable use of groundwater.

Laboratory of Experimental Rock Mechanics at EPF-Lausanne (LEMR)
(Laboratoire expérimental de mécanique des roches)

EPFL ENAC IIC LEMR
GC D1 401 (Building GC)

Station 18
CH-1015 Lausanne

Tel. +41 21 69 32372
Contact
Website (Englisch)

The Laboratory of Experimental Rock Mechanics at EPFL (LEMR) belongs to the School of Architecture, Civil and Environmental Engineering (ENAC). It provides research, teaching and services related to rock mechanics, rock physics, deep reservoir characterisation and coupled thermo-hydro mechanical processes in reservoirs, as well as engineering geology topics such as tunnelling and underground constructions.

Geozentrum Burgdorf
Bern University of Applied Science 
Architecture, Wood and Civil Engineering
Pestalozzistrasse 20
CH-3401 Burgdorf

Tel. + 41 34 426 41 74
Fax + 41 34 426 43 94
E-Mail
Website (Geozentrum Burgdorf)
Website (Berner Fachhochschule)

The Geozentrum Burgdorf is a collaboration between the Bern University of Applied Science
(department Architecture, Wood and Civil Engineering) and the Institute of Geological Sciences of the University of Bern. The laboratories of the Geocenter for Geotechnics and Engineering Geology support the teaching and research activities of both institutions and carry out a variety of material tests.

Institute of earth sciences of the Scuola universitaria professionale della Svizzera italiana (SUPSI)
(L'Istituto scienze della Terra)
Trevano, CP 72
CH-6952 Canobbio

Tel. +41 (0)58 666 62 00
Fax +41 (0)58 666 62 09
E-Mail
Website

 The institute is part of the Department for Environment Construction and Design of the University of Applied Sciences and Arts of Southern Switzerland (SUPSI). It deals with the management and protection of the environment and its resources. Its areas of expertise include geology, geotechnics, hydrology, hydrogeology and geomatics. 

Swiss Geotechnical Commission (SGTK)
ETH Zürich
NO F 35
Sonneggstrasse 5
CH-8092 Zürich

Tel. + 41 44 632 37 28
Fax + 41 44 632 12 70
E-Mail
Website

 Die SGTK, in collaboration with the Swiss Geological Survey, the Federal Office for the Environment (FOEN) and with private geology bureaus, produces the 1:200 000 geotechnical maps, the 1:100 000 hydrogeological maps as well as regional soil and rock maps.

Data

The construction site is to be evaluated, described and investigated in detail for the professional execution of construction projects.

The following are to be considered with an investigation and assessment of construction ground data:

  • geological and hydrogeological conditions
  • morphology
  • seismicity
  • natural hazards
  • building site history
  • contamination of the ground


The ground description contains the authoritative information and describes:

  • geological, hydrogeological and geotechnical maps including descriptive literature
  • hazard maps (avalanches, rockfalls, landslides)
  • aerial photographs
  • contaminated site register
  • databases and archives
  • information from neighboring exploration work
  • findings from neighboring or comparable project plans and structures
  • existence of groundwater and safety regulations


The site investigation must provide, in sufficient quality, all data about the ground and groundwater conditions which are essential for the planning, implementation and usage of the construction. It occurs in stages:

Preliminary investigation
Collection and analysis of relevant information which is needed for the design and planning of the main investigations.

Main investigation
Development of bases for the:

  • structural analysis (incl. a sufficiently safe and economic assessment of the structure)
  • organization of the construction’s execution
  • appraisal of the geotechnical and structural engineering difficulties and risks that may occur during the execution and utilization
  • assessment of the impact of earthquakes and natural hazards


Detailed investigation

Should the ground conditions be too complex, in-depth investigations are carried out, based on field and laboratory experiments that permit detailed clarification of special geological, geotechnical and hydrogeological phenomena.


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