Ground Condition Report

When constructing a building, one of the most important things to consider is the ground condition. The ground receives all the loads from a building. Any sign of instability from the ground is a fatal flaw for a building, since it could lead to a structural collapse. To avoid such matters, construction companies should include ground condition tests as a preliminary step before constructing a building. There are 4 methods for testing ground conditions, namely:

Boring

Borings, which are conducted by drilling contractors, can have different diameters, which allow for density evaluation via standard penetration testing (SPT) to physically remove soil or rock samples for assessment and testing. Borings offer the advantage of evaluating field density and observing the removed materials. Soil samples from the above tests are often taken to a lab for analysis. Borings allow stakeholders to install piezometers to monitor seasonal groundwater table instability.

Test pits

Trial pits are an intrusive site examination type of test that determines ground conditions across a site to assess or sample the subsurface structure and composition. A pit is dug, either manually or with a machine, to obtain a sample of the subsurface conditions at the required depth. Sampling procedures to be enabled include contamination tests, vane shear tests, infiltration tests, and CBR testing (in accordance with the guidance set out in BRE 365).

Trenching

Trenching follows the same process as test pits, but the excavation is extended over a distance to assess how subsurface conditions vary across the worksite. This approach enables the identification of various sedimentary changes over a larger distance. Trenching is also particularly beneficial in identifying ground models related to landslides, identifying old fill and disturbed material, and determining the depth of soft sediments.

In Situ Testing

In situ testing methods include drilling-based penetration tests such as Standard Penetration Tests (SPT), percussion-based inquiry techniques, sonic vibratory drilling methods, and various static direct push Cone Penetrometer Testing (CPT). In situ testing can produce a more accurate assessment of subsurface conditions, which allows for better data interpretation and informed geotechnical design.

In situ tests can be classified into three types. The first type is the empirical tests, where no basic analysis is possible because stress routes, drainage conditions, and rate of loading are either uncontrolled or inappropriate (for example, SPT). The second type is "semi-experimental testing.” Semi-empirical tests are those in which a limited relationship between parameters and measurements can be created. Lastly, the analytical studies regulate stress pathways but often do not regulate strain levels and drainage (vane shear strength, pumping tests, and packer permeability are some examples).