The geometrical modelling of rockmasses and their integration into underground projects: The use of remote sensing techniques (LiDAR) and numerical methods as part of an observational design methodology

Full Name: Ioannis Vazaios

Academic Affiliation: Department of Geological Sciences and Geological Engineering, Queen’s University

Position: PhD Candidate

 Abstract: Understanding the mechanical response of rocks and rockmasses is among the key factors that secure a sound and viable design especially in geotechnical and geomechanical engineering for a variety of projects including tunnelling, mining, slopes, building foundations etc.. In order to achieve this, different methodologies and techniques are employed varying from in-situ data collection to numerical simulations. However, depending on the project and the site-specific conditions, collecting data may be a rather difficult task due to the limited access and ground exposure. In such cases, stochastic geometrical models of a rockmass can be used in order to create a number of different but realistic scenarios of how the rock is arranged past the excavation (i.e. within the ground) in order to assess the variability of the in-situ conditions of the fractured rock. More specifically, in tunnelling and mining operations at great depths where the geotechnical investigation is usually limited, such models can be proven a useful tool in the engineering design process. Fracture (i.e. cracks or weak zones in the rocks) data used as input parameters for the stochastic modelling can be obtained by state-of-the-art remote sensing techniques such as laser scanning (LiDAR), which results in a high accuracy, 3D representation of the exposed fractured rock and can be integrated into the construction cycle efficiently and at minimal impact to the excavation process. Following the generation of the fracture geometrical models, these can be used within numerical codes in order to study the rockmass response under different excavation conditions. This is very important in areas where the geological conditions are complex, such as in the mainland of Greece whereby significant challenges have been seen to arise due to the multitude of tunnelling and mining activities that have taken place there in the recent past.