Lateral translation of a circular pile in cohesive soil: exact plasticity solution

Journal article

A fundamental problem in theoretical soil mechanics, and one with an interesting history, involves determining the lateral force per unit length required to translate a rigid circular pile (or other cylindrical object) through a body of rigid–plastic cohesive soil. A dimensionless factor α is typically used to specify the shear strength of the pile–soil interface relative to that of the soil. Previous studies using the method of characteristics, or slip-line method, have succeeded in establishing an exact solution for the special case of a fully rough pile (α = 1). The slip-line solution developed in this paper is shown to be exact (i.e. to give strict lower- and upper-bound collapse loads that coincide) over the full range of α, including the complementary special case of a perfectly smooth pile (α = 0). The exact value of the lateral bearing capacity factor N varies from 9.20117 to 11.9400 as α varies from 0 to 1. To verify that the incomplete slip-line stress field can be extended throughout the soil in a manner that is both statically and plastically admissible, over the full range of α, traditional analytical extension methods employing slip lines and stress discontinuities are supplemented by a novel numerical stress field extension technique based on finite-element limit analysis.

Authors: Martin, CM

• Publication status: Accepted
• Peer review status: Peer reviewed
• Publisher: ICE Publishing
• Journal: Géotechnique
• Acceptance date: 2026-02-19
• EISSN: 1751-7656
• ISSN: 0016-8505
• Language: English