Measures in the underground work method to determine the mathematical relations that predicts rock behaviour

Abstract

The perforation parameter measure was introduced in geological prospecting and in the mining, petrol and gas industry, becoming an efficient tool allowing one to identify in detail and predict the geological and geomechanical characteristics while drilling is being carried out. The field measures and the calibration requirements of the tools and equipment used, which constitute the main obstacle in the prediction model establishment. Analogously, in underground excavations, the continuous knowledge of the rock mass, geological and geomechanical properties in front of the excavation wall during the operations, is of great importance in designing optimum, and also in the planning of the work carried out by this equipment and machinery. Through intense work measure campaigns, in the present work, the mathematical relations obtained in tunnel boring through a percussion perforation in blasting by a jumbo and a tunnel boring machine (TBM) are shown. Considering percussion perforation blasting for the models establishment or for the drilling parameters recorders (DPR) and tool adjustment, parameters such as uniaxial compressive strength, specific cut energy and destructive energy were used. Considering TBM and taking into account the high variable number that intervene in the tunnel boring process and also based on easily obtained parameters such as the already defined specific cut energy and the penetration index, we have reached a relation between the latter parameters and the rock mass rating index (RMR), which allows to adjust and subsequently predict the geological exploration from data which were previously carried out (were carried out previously to the project).