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Synopsis One of the basic requirements of machine foundation design is the prediction of resonance in order to ensure that operating conditions lie well outside this critical state. The problem has been approached in various ways which are briefly reviewed. The evaluation of amplitude-frequency curves, obtained with experimental oscillators, is discussed. Empirical relations between resonant frequency and foundation area are shown to be consistent with an analysis based on the propagation of surface waves in an elastic medium. Une des exigences fondamentales dans la construction des fondations des machines est la prévision de la résonance afin de s'assurer que les conditions opératoires sont bien au delà des conditions critiques. Le problème a été approché de diverses manières qui sont passées en revue brièvement. L'évaluation des courbes amplitudes-fréquences, obtenues grâce à des oscillateurs expérimentaux, y est discutée. On montre que les rélations empiriques entre la fréquence de résonance et la surface des fondations s'accordent avec une analyse basée sur la propagation des ondes de surface dans un milieu élastique.

The volume change measurements of granular soils in triaxial testing are generally affected by penetration of the membrane enclosing the soil into the voids between the particles. The major factor influencing this penetration has been shown to be the particle size of the soil being tested. On the basis of the results of previous investigations and the present study, a relationship has been found between the membrane penetration and particle size. This relationship may be used to estimate the membrane effect for any granular soil.