Sand state from cone penetrometer tests: a framework considering grain crushing stress

Thekey factors that control the value of cone penetrometer tip resistance in cohesionless soils were assessed in order to develop a rational framework for interpreting the results of cone penetrometer tests (CPTs) that would allow confident determination of thein situ sand state. Using the University of Laval calibration chamber, measurements were made of the response of an instrumented cone tip in Ticino sand, Kenamu sand and Quebec sand placed at various densities and subjected to different initial stress levels. Triaxial compression tests were also performed on the same sands to define the relevant parameters at the critical state. It was established that it is important to consider the characteristics of a sand at which shear-induced grain crushing occurs, hence the bi-linear nature of the critical state line. The complete characterization of a sand by interpretation of CPTs is given by the void ratio, the mean effective stress at grain crushing and the slopes of the critical line (λ for stresses smal...