Mechanical characterization of rock materials across weathering spectrum: a comprehensive laboratory investigation of their engineering lithlogies from Southern Brazil

Abstract

Most engineering works in Southern Brazil are constructed on granitic rocks, basalt and sandstone. Complex and variable nature of weathering processes induced by tropical climate in this region produce intricate changes in composition and microfabric of these rocks deteriorating mechanical properties in a complicated way. This project aims at mechanical characterization of these three most important engineering lithologies across the weathering spectrum by a systematic and comprehensive laboratory investigation that includes three major components: microstructural and physical characterization; mechanical characterization by uniaxial and index testing procedures; and study of rock damage development. Employment of improved mechanical index test techniques on the indicated rocks of various weathering grades is given a special attention in this investigation in order to reduce the data scatter and for better assessment of degree of weathering and mechanical properties. Based on the entire analysis, a 'model' encompassing all investigated mechanical properties and interrelations with reference to weathering degree and notations about the performances of the mechanical index tests in characterizing the concerned rock materials would be developed. AH test results, analysis and the 'model' are expected to contribute appreciably to various engineering environments (e.g. site investigation, slope stability, rock excavation etc.) of Southern Brazil. (AU)