Non-destructive determination of Young’s modulus and its relationship with compressive strength, porosity and density

Abstract

Summary The Grindosonic apparatus, new equipment capable of indirectly determining rock compressive strength, is discussed. This utilizes the principle that elasticity theory can be applied to rock masses (Attewell & Farmer 1976; Selby 1982) and directly measures the fundamental vibration frequency of a rock sample of regular dimensions following shock excitation. Dynamic Young’s modulus and a variety of other parameters can be established. Samples of Upper Cretaceous Chalk and Upper Jurassic Portland Limestone are used to demonstrate the apparatus and its application. Test specimens were prepared and analysis conducted on material extracted at a number of locations throughout the Isle of Purbeck in Dorset, UK. Samples suitable for deformation in triaxial compression were also prepared and correlations drawn between compressive strength, dynamic Young’s modulus, porosity and density.