SCALE EFFECT FOR SHALLOW FOOTINGS ON DENSE SAND

In this effort to show that the lack of homogeneity of the granular medium caused by an isolated slip line explains the scale effect in a dense sand mass, an indication is given concerning the width of the footings sensitive to scale effect compared to the size of the grains of the sand. The slip-line formation is discussed and details are given of the scale effect in soil mechanics (case of dense sands). An analysis is described here which is based on the hypothesis of simultaneous slip and heaving, which is physically acceptable. This having been verified experimentally, the exploitation of the mechanical mode proposed can be attempted. If the scale effect in dense sand is linked to the dilatancy of the slip surface, it must disappear in two distinct cases: the dilatancy of the slip surface vanishes (the work due to gravity is zero); there is no slip (the deformation is homogeneous). The first case is that of clays and the second is that of soft clays and loose sands. It is concluded from the observations made in the paper that it is possible to situate and to interpret the scale effects obtained with dense sand when the stress field is vast homogeneous, especially in the presence of gravity. Such effects can appear in reduced models of all kinds as in the hydraulic gradient methods, or in centrifugation. In each case a precise analysis of these phenomena must be made in order to obtain a correct interpretation of the test results.

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  • Accession Number: 00260238
  • Record Type: Publication
  • Report/Paper Numbers: Proc. Paper 10254 Tech. Note
  • Files: TRIS
  • Created Date: Oct 11 1974 12:00AM