Strength testing calibration
Appropriate model parameterisation is important if dominant stability controls are to be identified. Central to this question is the reliability of strength testing to deliver material geotechnical properties. There is always the possibility that equipment is not be maintained to appropriate standards operating methods are not formally adhered to.
It is appropriate therefore to calibrate equipment with results reported from well documented testing laboratories. In this case, we undertook a set of direct shear tests using Leighton Buzzard sand in order that the results could be compared with those obtained by Lings and Dietz under differing levels of compaction [Lings, ML & Dietz, M.S. 2004 An improved direct shear apparatus for sand Geotchnique, 54,4,245-256].
Tests by undertaken by Lings and Dietz using allowed the performance of the direct shear apparatus to be optimised by exploring different configurations. The Lings and Dietz shear box using two states of compaction of Leighton Buzzard sand was taken as the benchmark against which the direct shear apparatus and testing procedure employed in St Lucia was compared. The results of this inter-comparison revealed that on the basis of this inter-comparison there was no evidence to refute the results obtained.