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Bifurcation analysis of deep boreholes: II. Scale effect
Author(s) -
Papanastasiou P. C.,
Vardoulakis I. G.
Publication year - 1989
Publication title -
international journal for numerical and analytical methods in geomechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 91
eISSN - 1096-9853
pISSN - 0363-9061
DOI - 10.1002/nag.1610130206
Subject(s) - borehole , bifurcation , compressibility , radius , stress (linguistics) , mechanics , finite element method , bifurcation theory , geology , mathematics , geotechnical engineering , physics , structural engineering , engineering , nonlinear system , computer science , linguistics , philosophy , computer security , quantum mechanics
Abstract This paper is a continuation of a previous one on bifurcation of deep boreholes under uniform stress at infinity, 1 and it focuses on the effect of borehole radius on borehole stability. Rock is described by the equations of a deformation theory of plasticity for cohesive‐frictional, incompressible materials with Cosserat structure. The inhomogeneous bifurcation problem is formulated and the corresponding eigenvalue problem is solved numerically by the finite element method. It is demonstrated that the combined Cosserat and stress‐gradient effects lead to an increase of the bifurcation stress with decreasing borehole radius (scale effect).