Behaviour of Singapore rocks under uniaxial and triaxial loading

Abstract

This report describes the strength and deformation behaviour of Jurong Formation sedimentary rocks in Singapore. With the need to develop future projects in this rock formation, the characteristics and design parameters for these rocks should be known. In this research, uniaxial and triaxial compressive tests as well as indirect tensile tests had been carried out on different sedimentary rocks, i.e. siltstone, limestone, sandstone and mudstone. During the tests, the axial and lateral deformations of the rocks were monitored against the stress level. In addition, acoustic emission and change in ultrasonic velocities during loading were recorded as well. From the results of the tests performed, the identification of crack initiation and propagation thresholds using the conventional stress-strain curve approach is more reliable compared to the acoustic emission detection and ultrasonic technique. In addition, the effect of confining pressure was found to be minimal on the various stress threshold ratios. Hoek-Brown and Mohr-Coulomb failure criterions were established for the various rock types for a range of confining stresses similar to the expected working stresses in these rocks. It is recommended that future investigation to be extended to higher confining pressures as well as improvements to the testing equipment and techniques.