Evaluation of small-strain shear modulus of Fontainebleau sand based on innovative pressuremeter probe testing in a calibration chamber

This paper presents an experimental study aimed at evaluating the measuring capabilities of an innovative monocellular pressuremeter probe, the Monocell Francis Cour® probe, based on calibration testing in the laboratory. The originality of the tested equipment is to allow to evaluate soil properties in both small and large strain domains, without the need of sophisticated punctual displacement measuring arms. This paper focuses on the evaluation of small strain shear modulus G of Fontainebleau sand, NE34, based on tests carried out with this specific pressuremeter probe. Shear modulus values obtained with this probe are then compared with values resulting from more classical elementary tests, showing a fairly good consistency. It is shown, with satisfactory agreement, that it is possible to quantify the influence of the density index of the sand as well as the influence of the mean effective stress around the probe on the shear modulus, based on the analysis of specific unload-reload loops performed during the test. The experimental programme carried out under well-controlled laboratory conditions allows to propose a validation of a method of identification of the shear modulus of sand at small strain levels using this prototype pressuremeter