Evaluation of Weathered Rock Mass Strength and Deformation Using Weathering Indices

Abstract

Rock weathering and the resulting effects on geotechnical properties of weathered rock mass has long been a concern for geotechnical engineering practicing since the strength and deformational properties of weathered rock masses is needed for analysis and design of underground openings, opens pits and excavations for foundations of dams, bridges and high-rise buildings in and on weathered rock mass. It is a very challenging task to obtain required core samples to determine the strength and deformation behavior for the assessment of weathered rock mass performance. This is because of weathering which causes change in fabric of rock by creating voids and micro cracks after dissolving grain boundaries particularly, at higher stage of weathering. This paper attempt to present a method of sampling and testing of weathered rocks and proposed a weathered rock mass indices chart for estimating rock mass strength and deformation properties. To investigate the applicability of the proposed weathered rock mass indices chart for other regions, available data from literature for same rock has been used along with the extensive testing data generated in the present investigation Deccan plateau basaltic rocks.