What Are Geotechnical Services?

Eugene Vargas

Geotechnical services are often offered by specialist engineering firms and they have a range of separate, though often related, functions. Geotechnical engineering comes under the umbrella of civil engineering and is essentially concerned with how earth materials behave in the environment. By gaining a better understanding of the ground at a particular site, it is possible to determine what sort of buildings can be built there and at what cost. A big part of modern geotechnical services, therefore, is surveying land prior to architectural building plans being drawn up.

Soil Testing Services

One of the first things that landowners should consider when choosing the best location for a development project is the quality of the soil. Poor soil is costly to build on and may require pile driving or extensive ground works before any buildings can even appear above the ground. In addition, soil testing — a primary geotechnical service — offers an accurate idea of the pH, sulphate and carbonate levels in the ground along with other important factors, such as clay sedimentation and soil density. All of these factors will impact on what sort of materials might be used in later construction. Undertaking such surveys often saves developers from a great deal of wasted expenditure by getting them to build in the right locations in the first place.

Slope Stabilisation

Another geotechnical service often needed in the construction industry is slope stabilisation analysis. On hilly ground, earth may move, especially if sections of it are removed to create terraces and there is flowing water to contend with. Geotechnical engineers are on hand to provide the necessary data to create retaining walls, culverts and embankments in such a way that buildings are able to withstand the pressure that slopes close by put them under. Because the underlying geometry of slopes is highly complex, engineers tend to use three-dimensional modelling software to achieve the best results.

Foundation Design

The size, shape and — most importantly — depth of foundations are commonly calculated by geotechnical services companies. This is especially true of sites which have had a previous industrial use, where the land is uneven or where there is a great deal of water, for example on marshes. Various methods are used by geotechnical engineers, such as the consolidation test, the triaxial shear test and the vane shear test, in order to establish whether standard foundations are appropriate or not. In some cases, so-called slab foundations are recommended, which underpin the entire structure, not just the walls, as a result of these sorts of tests.