Soil investigations are an important part of any construction project
A ground investigation will be utilised to discover the type of soil beneath the proposed building, and it will dictate the type and extent of foundations to be used.
A ground investigation is carried out by a specialist contractor, usually geological engineers with experience in the production of reports tailored to the construction industry.
There are several pieces of information that can be retrieved from the soil on any site. This can be the different soil strata present in the subsoil. The level of any water, or the water table, any contamination in the ground which could affect the occupants of the buildings and or the environment.
A ground investigation will provide useful information to the structural designers about the specific soil characteristic, water content, whether the soils are granular (Sands or Gravels) or cohesive (Clays or Silt). From a ground investigation test result it can be determined whether there are chemical and substances which can affect any structural elements buried in the ground and hence the structural engineer must ensure these constraints are mitigated during the design phase any risk is eliminated or reduced by implementing the required measures to avoid a hazard developing.
The soil type will define the type of foundation suitable for the imposed loading by the proposed buildings, for relatively small projects, i.e., 2 storey houses, generally strip or mass concrete trench footings are suitable, but where the solid conditions are not favourable such as very loose made ground or near a river or water stream the requirements for alternative options is needed. For larger and taller buildings, the need for piled foundations is often the norm, but this will depend on the information obtained from the ground investigation and the specific soil physical characteristics.