Numerical simulation of drilling-induced core damage and its influence on mechanical properties of rocks under unconfined condition

At the early stages of deep underground construction projects, data are primarily obtained from boreholes from which strategic decisions are made for the design of underground infrastructures. For this purpose, the unconfined compressive strength (UCS) and the Young's modulus (E) of intact rock as well as the in situ stress state are obtained as fundamental engineering parameters during the course of geotechnical site characterization. Unfortunately, drilling in relatively high stress environments can induce disturbance, micro-cracking of the cores, which in turn may result in lower rock strength and Young's modulus measured in the laboratory1 compared to their intact values or affect stress measurement results2,3 . This may lead to erroneous estimates of design parameters.