The geotechnical characterization of the rock mass for rock-embedded pile foundations describes the particularities and their conditioning factors, in this type of project ranging from prospecting to completion of the foundations. Depending on the investigations, the project may be designed and implemented using a better safer, more economical and faster technique. The investigation activities involved:
site: determining the Rock Quality Designation (RQD)and recovery using test cores, and
laboratory: determining the physical indices (dry and saturated specific mass, porosity and water absorption), and uniaxial compressive strength, and petrographic analysis
The characterization of the rock mass involved in building the foundations does not finish at the design phase but continues steadily as the project progresses, with the controlled accuracy to refine methods, re-dimension structures and adopt solutions for the overall project. Based on this, expedite rock drilling was also accompanied for the geotechnical characterization and control of the pile foundations, which was a good control tool for this type of foundation. It is also used for confirming the cap rock and verifying less resistant layers, before or during pile driving, simplifying the services, at a faster rate and lower cost. The analysis of the physical indices was compatible with the indices existing for this type of rock and the analyzed rock masses demonstrated good characteristics to support a foundation.
Investigations are one of the most important subjects in geotechnical engineering, specifically foundation engineering. Deep rock foundations are particularly relevant in this context, where, in addition to investigations, success also depends on follow-up and knowledge acquired during the construction phase.
The characterization of the rock mass involved in building the foundations does not finish at the design phase but continues steadily during construction. In spite of the development of numerical modeling methods, it will always be difficult to characterize and model the subsoil in geometrical and physical terms, including the rock masses. Although they are highly resistant, factors exist that significantly reduce the resistance of the rock mass and, consequently, the bearing capacity of foundation elements.
