Geomechanical properties of volcanic rocks from Deccan Traps, India

Volcanic rocks (Basaltic flows and pyroclastic deposit) have different geotechnical behavior as compared to non-volcanic rocks due to their more materials heterogeneity in nature. The variability of the composition, presence of voids, variable degree of cementing material and the geotechnical characteristics of inter bed unit in volcanic episode makes analysis and design of structures in volcanic rock more problematic. The aim of the present study is geotechnical characterization of Deccan trap volcanic rocks namely Compacted Basalt (CB), Volcanic Breccia (VB) and Tuff through laboratory testing and analysis. Block and core samples were collected from Deccan trap and then specimens prepared for petrographical studies and geotechnical property determinations as per standard protocols. The specimen prepared for petrographical studies analysed under Scanning Electron Microscope (SEM) with Energy Dispersive X-ray (EDX) to measure the microstructure and material composition of the three rocks. In addition to that the Index properties example density, specific gravity, porosity and water content were determined according to international society of rock mechanics (ISRM) protocols. The mechanical behaviour including compressive, tensile and triaxial strengths were also experimentally measured. The geotechnical property obtained through testing and analysis compared with literature and presented here in. The present work contributed geotechnical property of three volcanic rocks that can be used in primary design parameters assessment for the study area and in similar volcanic rocks elsewhere.