Intrinsic compression and swelling properties of a glacial till

Abstract

Abstract The heterogeneous tills of Northrn England and Scotland are difficult to sample and test if using standard UK site investigation practice which was primarily developed for soft to stiff sedimented clays and sands. Application of empirical correlations and theoretical models to help select design parameters that were developed from standard tests on natural and reconstituted sands and clays may not be correct for tills because of their different mode of deposition and spatial variation in particle size and type. A geotechnical model is needed to explain the behaviour of tills which includes studies of the deposition and post-depositional processes, intrinsic properties of reconstituted till, and a database of results of natural till. Results of one-dimensional and isotropic consolidation tests on reconstituted tills, reported here, have produced compression data that define the intrinsic compression line (ICL) and a band encompassing swelling lines over a pressure range of 6 kPa to 5 MPa. The intrinsic normal compression curves for the reconstituted tills agree with the ICL, therefore developments in the application of the ICL can be applied to tills. Furthermore, a unique band, defining the intrinsic swelling properties, has potential for a baseline for the interpretation of mechanical tests on natural till.