Seismic Earth Pressure Development in Sheet Pile Retaining Walls: A Numerical Study

The design of retaining walls requires the complete knowledge of the earth pressure distribution behind the wall. Due to the complex soil-structure effect, the estimation of earth pressure is not an easy task; even in the static case. The problem becomes even more complex for the dynamic (i.e., seismic) analysis and design of retaining walls. Several earth pressure models have been developed over the years to integrate the dynamic earth pressure with the static earth pressure and to improve the design of retaining wall in seismic regions. Among all the models, MononobeOkabe (M-O) method is commonly used to estimate the magnitude of seismic earth pressures in retaining walls and is adopted in design practices around the world (e.g., EuroCode and Australian Standards). However, the M-O method has several drawbacks and does not provide reliable estimate of the earth pressure in many instances. This study investigates the accuracy of the M-O method to predict the dynamic earth pressure in sheet pile wall. A 2D plane strain finite element model of the wall-soil system was developed in DIANA. The backfill soil was modelled with Mohr-Coulomb failure criterion while the wall was assumed behave elastically. The numerically predicted dynamic earth pressure was compared with the M-O model prediction. Further, the point of application of total dynamic force was determined and compared with the static case. Finally, the applicability of M-O methods to compute the seismic earth pressure was discussed

A note on the gaps between consecutive zeros of the Riemann zeta-function

Assuming the Riemann Hypothesis, we show that infinitely often consecutive non-trivial zeros of the Riemann zeta-function differ by at most 0.5155 times the average spacing and infinitely often they differ by at least 2.69 times the average spacing.Comment: 7 pages. Submitted for publicatio

Maintien des valeurs dans la croissance de la bio. Enseignements du projet HealthyGrowth

How do organic initiatives and food chains succeed in maintaining their foundational values along and despite their growth process? This question which appears central in the “conventionnalisation debate” has been tackled by the European project HealthyGrowth (2013-2016, Eranet Core Organic program). In this project, 11 teams from different countries developed and applied to 22 case studies, 5 different perspectives dealing with organization modes and governance, management strategies, communication of values, mediation of values, and resilience in a context of crises and changes. The cross analysis of these case studies, carried out through a multi-perspective approach, made it possible to identify 3 important aspects which allow maintaining values along the growth process: a continuous process of re-affirmation and sometimes redefinition of core values over time, a synchronization of time horizons that stabilizes the different actors’ expectations and commitments, and a process of professionalization which takes different forms and meanings