Analyse de la méthode P-RAT et caractérisation des argiles de la mer Champlain par la vitesse de propagation des ondes de cisaillement Vs

Abstract

The shear wave velocity Vs is a key parameter for seismic analysis which can also be used to characterize soil. In the literature, there are many empirical relations with Vs but few of them are for the Champlain clays. Therefore, the goal of this project is to characterize Champlain clays by Vs with the P-RAT method. In addition to increase the numbers of Vs measurements to the existing databank, this project aims to improve knowledge about the realization of these measurements that still present complex challenges. As the P-RAT method has proven its efficiency to measure Vs, this technique has been increasingly used. Therefore, the writer has undertaken to automatize the P-RAT method and to characterize with laboratory measurements the P-RAT rings with a double objective of improving the validity of the results and the conception of the piezoelectric rings. The results have first shown that the algorithm, which has been developed to automatize the P-RAT method, can only converge to a good value of Vs if the frequency window is known. Moreover, the results indicate that the frequency window seems to be changing during the test. Furthermore, changes have been observed depending on the type of soil and on the type of piezoelectric rings used during the test. In addition, the characterization of the P-RAT rings has shown that the different types of P-RAT model have an impact on the piezoelectric behaviour by reducing their resonance frequency and decreasing their displacement. Also, the impedance analyzer has been identified has a suitable device to characterize the P-RAT rings. Finally, ten samples of Champlain clays have been characterized with a consolidation test wherein P-RAT rings have been inserted. The analysis of the results shows that Vs would be influenced by the percentage of clay particles and the plasticity index.

Date	31 May 2019
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Yannic A. Éthier (Supervisor) & Mourad Karray (Co-supervisor)