Continuum and Discontinuum Analysis of Rock Caverns: Fid-Bau Portal

Continuum and Discontinuum Analysis of Rock Caverns

Usmani, A. / Pal, S. / Nanda, A.

Abstract Over the last decades, constructions of large underground rock caverns are experiencing a rapid development across the globe. However design and construction of these structures is a complex and challenging task, specifically with limitations of limited investigations data and presence of many uncertainties. Rock mass parameters along with joint configuration such as persistence, spacing and strength of the joints are the main factors which significantly modify stresses and displacements in the vicinity of the openings. Thus, a detailed cavern stability assessment based on field data collection from the excavated cavern’s face is critically important. This paper discusses continuum and discontinuum modelling of underground rock caverns based on case study of crude oil storage project located on southern coast of India. Critical points of observation for these two types of analysis are reviewed in reference to results of the case study. Data obtained from geotechnical monitoring of underground rock cavern is also compared and discussed with the results obtained from both continuum and discontinuum analysis for better understanding of the same. The results obtained from this study indicate that inclusion of discontinuities in rock mass for numerical modelling captures essential instability conditions around the cavern while continuum representation gives a more idealised illustration of the instability. Observed displacement values in most of the cases lie in between the calculated displacement values of continuum and discontinuum analysis.