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Abstract: Measured displacements in the upstream shell of rockfill dams show some settlements which can reach a few meters with water levels changes, especially during the first impounding, whereas downstream displacements are smaller. Complementary phenomena are responsible for rockfill collapse due to wetting. Here we numerically investigate the effects of buoyancy forces and the decrease in the coefficient of friction with water on a rockfill column maintained by vertical rigid walls and progressively filled with water. Numerical simulations of the settlements of the rockfill column, using the Contact Dynamics method, are presented. Buoyancy forces seem to have only a negligible influence on the granular pile. Decrease in the friction angle of the rock with water induces rearrangements of the medium, all the more as the decrease is significant. These dynamic rearrangements exhibit an irregular temporal evolution of the granular medium which can be characterized by a phenomenon of local “crisis”. Analysis of the settlements shows that these two combined effects are not the major cause of the settlements observed in rockfill dams and that they cannot in particular explain the settlements. [Copyright &y& Elsevier]

The underground transit system of the Paris metro was built in the early 20th century. Many tunnels and galleries of this underground system were constructed with old masonry whose properties have changed with time and increasing use, and its strength may have deteriorated under the impact of several weathering factors. Therefore, research has been initiated to diagnose structural deterioration of the tunnels and galleries used by the Paris metro system. This paper outlines the current state of the metro galleries in which cracks have developed in the tunnel lining caused by degradation of the abutment materials. The initial state of the stresses applied to the structure immediately after the construction is also analyzed through a double comparison (analytical–numerical and numerical 2D–3D). Then the damage of the galleries is modeled by taking into account the effect of the tunnel linings’ reduced strength. By means of an equivalent homogeneous model and a strain-softening approach, deformations associated with crack appearance can be located. The numerical results show that the state of different components of the underground structure during the lifetime of the galleries can be assessed. [ABSTRACT FROM AUTHOR]

In order to protect infrastructures against rockfalls, civil-engineered mitigation measures are widely used. Flexible metallic fences are particularly well suited to stop the propagation of blocks of rock whose kinetic energy can reach 5000 kJ before impact. This paper focuses on the design of highly flexible rockfall fences under the new European guideline ETAG027. The experimental testing and the numerical modeling using the discrete element method (DEM) of a new metallic rockfall fence are presented. Several scales of study were considered; the mesh, the net and the entire structure. The calibration of the DEM models is described and a parametrical study is proposed. The latter aims to underline the type of information that can be obtained from numerical simulations of such a system to enhance its design. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented regarding G-CSF-induced thrombocytopenia in a healthy donor.