Wei Dong Guo

Model tests were conducted on vertically loaded single piles in sand subjected to either a uniform or a triangular profile of soil movement. Results of four tests are presented herein in the form of maximum bending moment (M_max), shear force, and pile deflection profiles. The evolution of the pile response with frame movements is examined, regarding the effects of soil movement depth and profiles, and axial load using the measured moment and deflection. In particular, the triangular profile causes 95∼160% higher `ultimate' M_max than the uniform movement does. The vertical load causes 5∼17% higher value of the M_max.

In this paper, closed form solutions were employed to predict nonlinear response of pile groups gained previously using FLAC^3D, centrifuge tests, and 1g model tests. The study shows (1) impact of pile-pile group interaction and high loading eccentricity is well captured; (2) The magnitudes of bending moment reported are not highly accurate in pertinent numerical simulations and model tests; (3) Quality tests, especially on large pile groups are required. Hand-calculation is elaborated via a typical example to highlight the features and use of the solutions to gain nonlinear response. It demonstrates the efficiency and accuracy of the solutions for relevant design.

In spite of extensive studies on laterally loaded piles carried out over years, none of them offers an expedite approach as to gaining the nonlinear response and its associated depth of mobilization of limiting force along each pile in a group. To serve such a need, elastic–plastic solutions for free‐head, laterally loaded piles were developed recently by the author. They allow the response to be readily computed from elastic state right up to failure, by assigning a series of slip depths, and a limiting force profile. In this paper, equivalent solutions for fixed‐head (FixH) single piles were developed. They are subsequently extended to cater for response of pile groups by incorporating p‐multipliers.The newly established solutions were substantiated by existing numerical solutions for piles and pile groups. They offer satisfactory prediction of the nonlinear response of all the 6 single piles and 24 pile groups investigated so far after properly considering the impact of semi‐FixH restraints. They also offer the extent to ultimate state of pile groups via the evaluated slip depths. The study allows ad hoc guidelines to be established for determining input parameters for the solutions. The solutions are tailored for routine prediction of the nonlinear interaction of laterally loaded FixH piles and capped pile groups. Copyright © 2008 John Wiley & Sons, Ltd.

Response of a pile subjected to torsional loading is significantly affected by soil profile. To investigate this characteristic, pile-soil interaction may be modeled by a series of independent springs distributed along the pile shaft (load transfer model). With this modeling, in this paper, analytical solutions are developed for the pile embedded in a two-layered soil profile. The soil stiffness of each layer is assumed to increase as a simple power law of depth, starting with any value at ground level. The solutions are expressed in terms of Bessel functions of noninteger order; and also presented in simplified expressions for some special cases. The solutions are verified using a spreadsheet, numerical program GASPILE, which is based on a nonlinear load transfer model. They are further collaborated using more rigorous numerical approaches available for a two-layered homogeneous soil. With the solutions, extensive parametric study was conducted and presented in nondimensional charts, in order to show con...

Response of a pile due to lateral soil movement and axial load has been investigated extensively by the authors. Typical results deduced from single pile tests in sand are presented previously in terms of effect of pile diameter, soil movement profile, sliding depth and magnitude of axial load. In this paper, a brief description of the apparatus was presented. Results from two model tests were reported, which were conducted on two instrumented pile groups embedded in sand subjected to a uniform lateral soil movement at a sliding depth of 0.57L (L = pile embedment length). Analysis revealed the effect of the direction and depth of soil movement, together with the magnitude of axial load, which are illustrated via profiles of bending moment, shear force, soil reaction, and pile deflection along instrumented piles in groups at various stages.