DFI Journal - The Journal of the Deep Foundations Institute
Volume 18, Issue 2, November 2024
DOI: 10.37308/DFIJnl.20231025.302
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Characterizing residual strength of p-y curves for rock-socketed pile shafts
Article Type: Research Paper
Khosravifar, A.
Abstract
Rock-socketed pile shafts are an effective choice of foundation for heavy structures (e.g., bridges, wind turbines, etc.). One of the primary challenges in the design of rock-socketed shafts for lateral loads is the characterization of residual strength in p-y curves in rock. For example, in the Strong Rock p-y curves that are commonly used in practical applications, the assumed brittle response of fractured rock results in nearly zero residual strength. However, there is no experimental evidence for this drastic drop in the residual strength of fractured rock. The drastic drop in the lateral reaction of p-y curves may result in unreasonably long rock-socket lengths causing constructability issues and unnecessarily increase the construction costs. This paper proposes modifications to the residual strength of p-y curves that can be implemented in existing rock p-y curves. Data from a lateral load test was used to develop a three-dimensional numerical model in FLAC3D using the Hoek-Brown constitutive model for rock. The 3D numerical model was then used to characterize the residual strength of rock p-y curves. The proposed residual strength was implemented in Strong Rock p-y curves in LPILE to model a lateral load test and to illustrate the application of the proposed modifications in a practice-oriented numerical tool.
Keywords:
Piles, rock-socketed shafts, p-y curves, residual strength