Geotechnical Investigations & Foundation Solutions

As an essential requirement for any new construction, and in order to obtain a Building Consent, a detailed geotechnical investigation must be undertaken to better delineate the soil profile. The results should be analysed to identify the risk of liquefaction-induced future differential settlement as well as to determine the inferred ultimate bearing capacities across the building footprint, before providing recommendations for likely suitable foundation systems. In addition, and whenever appropriate, any ground remediation requirements will be addressed to improve the soil characteristics and bring it to acceptable level that can support the future structural load adequately (as required by current standards).

Project example

Eliot Sinclair was engaged to undertake geotechnical investigations and provide foundation solutions / recommendations, including ground improvement, for new commercial and industrial buildings in Christchurch CBD area. Intensive deep and shallow site investigations were undertaken across the site. The investigations indicate the site is underlain by sandy gravel fill with a high level of debris contents, over buried silty topsoil fill to 1.2m below ground level. The fill was potentially contaminated and does not provide adequate bearing capacity to support the new building loads.


The buried topsoil should be stripped by excavating down to around 1.2m depth, before backfilling in accordance with New Zealand standards. In order to reduce the cost associated with disposing off-site the excavated gravel fill and importing large quantities of clean backfilling materials, the clean excavated gravels can be reused as engineering fill after removing all the buried topsoil and organic matters, and any other unsuitable materials. These materials should be placed at the lower layers of the backfill, and then followed by imported sandy gravel across the upper layers. This process can ensure adequate bearing capacity to support ground beam foundations.

Future enhancement

Eliot Sinclair & Partners Ltd will continually provide reliable, high integrity site investigation program that best fits our clients requirements.

Whether you are considering constructing a new home, an office building or industrial/commercial structure, Eliot Sinclair can provide the most professional geotechnical expertise