Young-nam Lee

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


For the design and construction of underground structures in swelling rocks, it is important to understand the time-dependent deformation behaviour and develop the stress-strain-time relationships for the analysis of the rock-structure-time interaction problem. This thesis deals with these two areas of research.;Four new test apparatus were designed and constructed for the measurement of time-dependent deformation in three orthogonal directions for the study of the swelling behaviour of the Queenston shale from Niagara Falls, Ontario. Using the new and existing test apparatus, six types of time-dependent deformation tests were performed on samples prepared from oriented rock cores of the Queenston shale. In addition, a specially designed test program was carried out to investigate the mechanism of the swelling of the shales.;The general stress-strain-time relationships in three dimension were formulated using the results of time-dependent deformation tests. A new methodology was developed and found to be capable of taking into account the non-linear swelling deformation response under uniaxial and biaxial stress conditions.;The main conclusions that have emerged from this course of the study are: (1) The time-dependent deformation behaviour of the shale is essentially cross-anisotropic with higher swelling potential in the vertical direction and is strongly stress-dependent. (2) The necessary and sufficient conditions for swelling to occur due to unloading are (a) the relief of initial stress, (b) the accessibility to water and (c) an outward salt concentration gradient from rock to ambient fluid. (3) The general stress-strain-time relationships developed are found to be adequate for the prediction of the non-linear swelling deformation response of the Queenston shale under applied uniaxial and biaxial states of stresses.



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