Contributions of numerical modelling to the design of large storage caverns in weak jointed chalk

By taking the design and construction of a large underground storage facility in weak jointed chalk as a case history, the use of numerical modelling by the Finite Element Method is discussed as a valuable design aid, coupled with rock mass characterization and monitoring during excavation. It is shown that very significant benefits can be realised in such a case for interpretation of laboratory and in situ testing, assessment of deformation-stability conditions, and evaluation of performance monitoring during cavern excavation. Also addressed is the adoption of numerical modelling for the purpose of refining the values of design parameters, in order to be able to predict the mode and magnitude of the rock mass response to the development of the excavation and in view of dimensioning the structural liner.