Various Assessments of the Characteristic Values of Soil Cohesion and Friction Angle: Application to New Caledonian Laterite

Abstract

In situ measurements, as well as laboratory tests, yield varied information on ground material. In order to carry out computations, it is necessary to reduce the scattered and uncertain information to a characteristic value. The approach used to derive this charac- teristic value is seldom explained in the literature. Yet, this data-simplification methodol- ogy may influence results by virtue of both the choices adopted for data collation and the computation methodology. Studies conducted on the properties of New Caledonian lateritic materials, for the purpose of guiding the design of open pits and dumpsites, have led to collecting result on a variety of triaxial tests. A number of different collation and statistical interpretation techniques for these tests have been attempted and have led to significantly distinct average cohesion and friction angle values. This paper underscores, in the specific case of New Caledonian laterite, the variability of results due to the way in which data are interpreted and the impracticality of justifying one methodology over another. It shows either the importance of taking great caution when defining practical rules and design for these constructions.