Effect of Smear Distribution on the Load-Bearing Mechanisms of Rock-Socketed Piles in Soft Rocks
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 150, Issue 1
Abstract
The design of rock-socketed pile foundations requires careful consideration of critical construction aspects such as the socket roughness and smear for accurately estimating the shaft load capacity. Despite the effect of smear being investigated extensively over the years, previous studies are limited in accurately characterizing the effect of smear on the shaft response. This paper presents a comprehensive investigation on the load-bearing mechanisms of model smeared rock-socketed piles with different smear fabrics (configurations) at the pile-rock interface. These model piles were loaded into synthetic soft rocks while being intermittently subjected to three-dimensional (3D) X-ray computed tomography (CT) imaging. Interpretations from the X-ray CT images were correlated with the pile-head load-displacement behavior to gain insights into the load transfer attributes between the pile, smear, and rock. The various interactions between these components were deduced by monitoring the micromechanics at the pile-rock interface through shaft energy utilization, interface void volume, smear volume, and sand density mapping. Based on the observations, it was inferred that the load transfer between the smear and the rock is primarily dependent on the percentage and position of smear occupancy at the interface. Results indicated that for the partially smeared interfaces, the interface mechanics are a combination of smeared and clean shafts with the residual resistances dependent upon the combined compression of smear and rock debris at the interface. Moreover, it was observed that the continuous presence of smear for more than half area of the leading faces of the pile asperities results in the smeared regions of the pile taking precedence over the unsmeared regions in governing the load-carrying capacity of the shaft. The discussions presented in this study can provide a strong base to further study the smear effect, subsequently aiding in enhancing the existing design guidelines to economically construct piles in soft rock.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request (raw X-ray CT images and MATLAB version R2017B codes).
Acknowledgments
This study was carried out as a part of the Ph.D. program at Monash University. The first author is grateful for the Monash International Tuition Scholarship (MITS) and the Research Training Program (RTP) stipend provided by the Australian Government for the doctoral study. The x-ray microscopy facility established through the Australian Research Council Linkage Infrastructure and Equipment Fund (LE130100006) and the laboratories at the Department of Civil Engineering of Monash University are highly acknowledged.
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Journal of Geotechnical and Geoenvironmental Engineering
Volume 150 • Issue 1 • January 2024
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© 2023 American Society of Civil Engineers.
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Received: Dec 14, 2022
Accepted: Sep 7, 2023
Published online: Nov 6, 2023
Published in print: Jan 1, 2024
Discussion open until: Apr 6, 2024
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Cited by
- Arun Kumar Murali, Asadul Haque, Ha H. Bui, Khoa M. Tran, DEM Modeling of the Load-Bearing Mechanisms of Rock-Socketed Piles with Soft Interface Materials, Journal of Geotechnical and Geoenvironmental Engineering, 10.1061/JGGEFK.GTENG-12279, 150, 7, (2024).