An analytical-numerical formulation is presented for dynamic and static analysis of strip foundations on an elastic isotropic medium consisting of heterogeneous layers. Each layer is characterized by an s-wave velocity that increases or decreases linearly with depth, a constant material density, a constant Poisson's ratio equal to 1/4 and a constant linearly-hysteretic critical damping ratio. The solution, based on a transformation that uncouples the wave equations in closed-form, is "exact" in that it properly accounts for the true boundary conditions at the layer interfaces and the surface. Results are presented for two characteristic soil profiles (half-space and stratum on rigid rock) in the form of normalized load-displacement ratios as functions of key dimensionless factors that influence the foundation behaviour during static and dynamic vertical, horizontal or moment loading. An interesting equivalence is established between a heterogeneous and a homogeneous halfspace, both having the same moduli at a depth equal to the foundation halfwidth (for translational motions) or to 1/2 the foundation halfwidth (for rotation), i.e. For low frequency factors, the two media yield displacements of about the same average level, although the occurrence of resonance phenomena due to total wave reflection in the heterogeneous medium leads to fluctuations of the corresponding curves around the mean values. (Author/TRRL)

Media Info

  • Features: Figures; References;
  • Pagination: p. 159-177
  • Serial:
    • Volume: 30
    • Issue Number: 2
    • Publisher: Thomas Telford Limited
    • ISSN: 0016-8505

Subject/Index Terms

Filing Info

  • Accession Number: 00330797
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Aug 15 1981 12:00AM