Geotechnical characteristics of siliceous North Sea sands

Abstract

When deriving drained strength parameters for sandy soils, geotechnical engineers need to be cautious while applying the semi-empirical correlations that are mainly developed from the highly idealised uniform clean silica sands as often used in academia. Many studies have shown that changing fines content changes the mechanical behaviour of sand, and that grading curve and particle angularity affect the strength-dilatancy characteristics. However, when various parameters of sands encountered in nature differ from the commercially sourced silica sands, the counteracting effects are difficult to quantify. In this study, a database of classification tests and Consolidated Isotropic Drained axisymmetric strength tests as well as some accompanying cone penetration tests (CPTs) are collected for siliceous sands from the North Sea. From this extensive database of natural sands, simple expressions are developed to help predicting drained strength parameters with improved reliability. Furthermore, a correction factor, for a commonly applied CPT friction angle qc − φ′p , tx correlation accounting for the grading curve, is developed. These expressions can help in reducing the number of costly advanced strength tests and to gain more information from a soil investigation.