The anisotropy of granular materials

The effect of the anisotropy on the elastoplastic response of two dimensional packed samples of polygons is investigated here, using molecular dynamics simulation. We show a correlation between fabric coefficients, characterizing the anisotropy of the granular skeleton, and the anisotropy of the elastic response. We also study the anisotropy induced by shearing on the subnetwork of the sliding contacts. This anisotropy provides an explanation to some features of the plastic deformation of granular media.Comment: Submitted to PR

Skin friction of a single pile to bedrock

A kinematically admissible displacement field describing the movement of the particles of a clay body surrounding a single prebored end-bearing vertical pile is used to obtain the nature and variation of the tangential component of the traction vector acting on the pile surface. The clay is assumed to be saturated, uniform and underlain by bedrock having a surface loading of p 1[~](t) where 1[~](t) is the unit step function.Les auteurs calculent les \ue9l\ue9ments du syst\ue8me des d\ue9 placements cin\ue9matiques possibles repr\ue9sentant le mouvement des particules d'une masse d'argile entourant un pieu vertical \ue0 pointe portante, moul\ue9 dans le sol, en vue de conna\ueetre la nature et la variation de la composante tangentielle du vecteur de traction agissant a` la surface du pieu. On consid\ue8re que l'argile est satur\ue9e, d'une composition uniforme et qu'elle repose sur la roche en place supportant une charge de p l[~](t) dans lequel l [~](t) est une fonction en escalier de Heaviside.Peer reviewed: NoNRC publication: Ye

Settlement observations at Kars Bridge

A 26-ft.-high approach fill was constructed in November 1959 for a bridge over the Rideau River near Kars, Ontario. The fill was placed over 50 ft. of Leda clay, the lower 30 ft. of which was extremely sensitive and compressible. Prior testing indicated that the preconsolidation pressure of the clay would be exceeded. Settlement gauges and piezometers under the fill have been observed since the start of construction. After 7 1/2 years, 20 in. of settlement has occurred under the centre of the fill. Settlements are continuing at an appreciable rate although the excess pore water pressure has dissipated to a low level and is nearly constant through the clay layer.Un remblai d'approche de 26 pieds de hauteur fut construit en novembre 1959 pour un pont sur la rivi\ue8re Rideau pr\ue8s de Kars en Ontario. Ce remblai fut \ue9rig\ue9 sur une couche d' argile Leda profonde de 50 pieds dont les 30 pieds de base \ue9 taient extr\ue8mement sensibles et compressibles. Des essais avaient d\ue9montr\ue9 que les pressions de pr\ue9consolidation seraient d\ue9pass\ue9es. Depuis le d\ue9but des travaux et jusqu'\ue0 ce jour des lectures ont \ue9t\ue9 faites tant sur des jauges de tassement que sur des pi\ue9zom\ue8tres plac\ue9s sous le remblai. Ces lectures r\ue9v\ue8lent qu'il s'est produit au cours des 7 1/2 derni\ue8res ann\ue9es, 20 pouces de tassement au centre du remblai et que ces tassements s'effectuent toujours \ue0 un rythme appr\ue9ciable en d\ue9pit du fait que les pressions interstitielles aient pr\ue9sentement atteint un niveau moindre et soient de presque \ue9gale intensit\ue9 \ue0 travers la couche d'argile.Peer reviewed: NoNRC publication: Ye