飽和砂の繰り返し一面セン断試験に関する実験的研究

概要

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The usual type of direct shear test apparatus was improved to be sheared repetitionally in order to obtain the approximate characteristics of repetitional shear of soils. The authors have reported formerly some results of dry sand using the above apparatus. Herein, some experimental results on saturated sand are shown using the same apparatus.The experiment was conducted in three kind of relative densities (Loose state: D_r=25%, Medium state: Dr_=54%, and Dense state: D_r=78%), and Toyoura uniform sand was used. The shearing test are conducted in two cases, such as: 1) Single direction shearing, 2) Repetitional shearing under a given displacement.The following results are obtained: 1) The shearing resistance τ_m increases as the repetitional cycles N increases during the displacement of repetition of cycles D_H (x 10^<-2> mm) smaller than ±150 in dense state, ±200 in medium state, and ±300 in loose state. 2) The hystorical damping factor h obtained here was in the range of h=26.0～31.5%. 3).The angle of shearing resistance φ obtained after repetitional shear test show a slight increase comparing with the single direction shearing when the repetitional displacement was conducted under D_H=±50～±100. The increasing of φ could be consider as the density increasing caused by the repetitional shearing.
琉球大学工学部の論文