Deformation parameters of bedrock at a nuclear reactor site

Abstract

Many engineering structures have to be founded deep into rock or on rocks, especially in a nuclear reactor site. Numerical finite-element and boundary-element analyses for studies of the stress and displacement distribution of any rock engineering projects are based on deformation parameters. Empirical relations are available to relate the rock mass deformation modulus to index properties, but the equations include some uncertainties relating to the variability of rock type and the heterogeneous nature of the rock masses. For important structures, site-specific parameters have to be evaluated to assess strains and stresses in rock due to various load combinations. Pressuremeter tests, cyclic plate load tests, uniaxial jack tests and seismic crosshole tests were conducted to evaluate in situ design parameters. The objective of this paper is to evaluate deformation parameters of a prototype fast breeder reactor from these in situ tests. For high strain deformation modulus, the pressuremeter modulus is comparable with the rock mass modulus obtained from laboratory results in association with rock quality designation. Crosshole tests results are used for evaluation of low strain modulus.

Editorial

“…The authors demonstrate how use of a trial embankment, supporting laboratory methods and the observational method allowed the efficient design of a major railway embankment in difficult ground conditions. The theme is continued by Harikumar et al (2013) who argue that it is important to obtain site specific in situ measurements for modelling and understanding the performance of rock in the design of important structures rather than adopting commonly used empirical approaches or assumed parameters. In this case the development is a nuclear reactor facility.…”