Análisis retrospectivo del cálculo de muros pantalla de la línea 16 del Grand Paris

Abstract

ABSTRACT: This Master’s degree thesis aims to study the real behavior of the multi-butted flexible retaining walls executed in the framework of the Grand Paris Express project. The work consists of the back-analysis of the calculation of the diaphragm walls and the struts based on the monitoring data collected during the construction of the lot 1 of the line 16 of Grand Paris project. The objective is to deepen the knowledge of the behavior of the diaphragm walls and the struts and to propose some recommendations to be considered in future projects. The back-analysis concerning the calculation of diaphragm walls presents the study of 36 calculation sections. The available inclinometer data allow the study of the deviations of the horizontal displacements between the real behavior of the diaphragm walls and the estimates obtained from the subgrade reaction coefficient modelling. The calculation hypotheses are therefore analyzed through the calibration of the initial modelling. The behavior of the singular sections is also discussed in detail and deepened with the proposal of a method for the estimation of the displacements of the diaphragm walls. In turn, the struts of diaphragm walls are studied through a back-analysis based on the measurements of the available extensometers. An initial study of the compressive forces in the struts is carried out. This study aims to quantify the differences between the measurements collected and the estimations calculated in the design phase. In addition, the thermic effect in struts also is analyzed in detail with the study of the thermic gradients and the degrees of restriction of the supports