Borehole Investigations

Abstract

The direct study methods used in engineering geology are based on geotechnical surveys, which allow for the sampling of subsurface materials and the undertaking of in situ tests. Boreholes are drilled by percussion or rotary techniques, with the latter being the most common. Different types of tools are available to obtain disturbed and undisturbed samples. Undisturbed samples are those that best maintain the physical structure and properties of the soil and lead to more reliable laboratory test results. Tests undertaken in situ in a borehole include penetration tests, pressuremeter and dilatometer tests, and permeability tests. All of these, together with the ones performed in the laboratory on the samples obtained from the boreholes, are essential to understand the characteristics of the soil and to design engineering works to be constructed at the study site.