The coefficient of dynamic soil reaction to pile motion is investigated on the basis of a continuum model to provide information when soil is moulded as discrete springs and dashpots. The horizontal response is derived assuming: a homogeneous soil stratum underlain by a rigid bedrock a linear viscoelastic soil material with a constant hysterelic dampings, a cyclindrical elastic pile driven to the bedrock, no vertical soil movement in horizontal vibration, no relative movement at the soil pile interface, and harmonic motions. Under these conditions, the coefficient along the pile varied with depth, z, and relative stiffness of soil and pile, these variations being especially pronounced when the soil is much stiffer than the pile and when the pile is shorter under a constant Y. The local stiffness and damping constants of the soil surrounding the pile can vary greatly with depth, frequency and relative stiffness of the pile and the soil, expecially at frequencies below the fundamental frequency of the layer. At frequencies higher than the fundamental natural frequency of the soil deposit, the soil medium can be treated more favorably as uncoupled springs and dashpots distributed along the length of pile. At any particular frequency, such a treatment is more favorable for stiffer piles and deeper soil deposits. The constants of these springs and dashpots can be obtained from the cylindrical plane strain condition, and therefore, are independent of the piles parameters. Although the coefficients of soil reaction are examined here only for the horizontal mode of vibration, the arguments presented are also valid for all other vibrational modes.

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  • Accession Number: 00314623
  • Record Type: Publication
  • Report/Paper Numbers: ASCE 15433
  • Files: TRIS
  • Created Date: Oct 8 1980 12:00AM