Pseudo-dynamic bearing capacity of strip foundations on rock masses considering the Rayleigh surface waves

Abstract

Evaluation of seismic bearing capacity is to be vital for design of strip foundations in earthquake areas. Combining the upper bound theorem of limit analysis, the discrete technique is successfully extended in this study to investigate the seismic ultimate bearing capacity of shallow strip foundations on rock masses considering the Rayleigh waves, in which the nonlinear HB failure criterion is used to describe the constitutive relation of rock masses. The failure model of foundation soil is generated using the discretization method, a “point by point” technique. The variations of shear modulus G of rock masses and seismic acceleration varying with the depth are taken into consideration. The generalized tangential technique is employed to avoid the difficulty resulting from the nonlinear HB failure criterion. A linear corresponding to the Mohr–Coulomb failure criterion, tangent to the nonlinear Hoek–Brown failure criterion, is used to derive the objective function that is to be minimized. By comparing with the existing results, the present approach is verified. The widely parametric studies are made to investigate the effect of different parameters, e.g. shear modulus G, mi, GSI, σci, γ, D, VR, on the seismic bearing capacity of strip foundations. The present method provides a reference for strip foundations designed in earthquake areas.

Keywords

• Strip foundations
• Seismic bearing capacity
• Rayleigh surface waves
• Limit analysis
• Discretization technique
• Hoek-Brown criterion