11 Scopus citations

Abstract

Transient response of a permeable cylindrical borehole arises from dynamic loadings applied to the borehole internal surface. Biot's theory of poroelastodynamics is used in this work to study the dynamic response of a circular borehole in a fluid-saturated medium under a non-hydrostatic initial stress state. Using the Helmholtz decomposition for the displacement fields, analytical solutions for the stresses, displacements, pore pressure are derived in the Laplace-Fourier transform domain; and the superposed solution of the axisymmetric mode and the asymmetric mode is inverted numerically to the real time domain using a reliable numerical scheme. Influences of the dimensionless poroelastic parameters on the dynamic response of the borehole are analyzed in a detailed parametric study. Radial variations of the pore pressure and stresses in the two different modes are examined; and the dynamic evolution of the superposed solution is analyzed. A direct comparison between the classical quasi-static poroelastic theory and current poroelastodynamic theory shows that inertial effect is important in early times; and the poroelastodynamic response resembles a damped oscillator, exhibiting wave-diffusion behavior. At longer times, diffusion dominates and the poroelastodynamic solution approaches the quasi-static poroelastic solution. The presented solution can be applied to study borehole stability under dynamic loadings.

Original languageEnglish (US)
Pages (from-to)82-93
Number of pages12
JournalInternational Journal of Rock Mechanics and Mining Sciences
Volume93
DOIs
StatePublished - Mar 1 2017

Keywords

  • Analytical solution
  • Laplace-Fourier transform
  • Non-hydrostatic stress field
  • Poroelastodynamic response

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology

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