Abstract #
This paper presents a back-analysis of field loading tests on bored piles and drilled shafts performed in tropical soil at the University of Brasília’s experimental research site. The numerical simulations were conducted using the GEO4 software from FINE Inc., which computes the load-displacement curve at the pile head and the distribution of normal and shear forces along the shaft. The study employs a modified Mohr-Coulomb failure criterion to describe the shear behavior of the pile-soil interface, focusing on the determination of key geotechnical parameters such as friction angle, cohesion, and Young’s modulus. The findings underscore the importance of these parameters in deep foundation design, especially in tropical soil conditions.
Technical Relevance #
This document is essential for geotechnical engineers working on deep foundation projects in tropical regions. The integration of field test data with numerical analysis provides a comprehensive understanding of pile behavior in challenging soil conditions, offering practical insights for optimizing foundation design using advanced software tools like GEO4.
Target Audience #
The document is intended for geotechnical engineers, civil engineers, researchers, and professionals involved in foundation design and analysis, particularly in regions with tropical soils. It is also valuable for academics and students studying the application of numerical methods in geotechnical engineering.
Software and Methodology #
The numerical analysis was carried out using the GEO4 software, which models the pile-soil interaction using a semi-analytical procedure. The pile is discretized into finite elements, and the soil-pile interface is modeled using nonlinear soil springs based on the modified Mohr-Coulomb failure criterion. The study involves calculating the geostatic stress, shear force, and load-displacement behavior at various depths along the pile shaft, considering different soil layers and construction techniques.
Process Description #
The paper begins with a description of the geotechnical characteristics of the site at the University of Brasília, focusing on the tropical clay and saprolitic soil layers. The study then details the methodology for conducting field load tests on bored piles and drilled shafts, followed by the setup of the numerical model in GEO4. The process includes a comparison between the experimental load-displacement curves and the results obtained from the numerical simulations, highlighting the accuracy of the model in predicting pile behavior.
Main Findings #
The study finds that the GEO4 software can accurately simulate the load-displacement behavior of bored piles in tropical soils, provided that the input parameters are carefully calibrated based on site-specific data. The results emphasize the critical role of soil cohesion and the friction angle in determining the load-bearing capacity of the pile. The research also suggests that the construction method significantly influences the soil-pile interaction, affecting the overall stability and performance of the foundation.
Practical Applications #
The findings from this study are directly applicable to the design and analysis of deep foundations in tropical regions, particularly for projects involving bored piles and drilled shafts. Engineers can use the insights gained from this research to improve the accuracy of their numerical models and make informed decisions about construction techniques to optimize foundation performance.
Limitations and Considerations #
The document acknowledges that the results are based on specific geotechnical conditions found in Brasília, and the methodology may need to be adapted for use in other regions with different soil properties. The study also highlights the importance of conducting field tests to calibrate the numerical model and ensure reliable predictions of pile behavior.
Conclusions #
The paper concludes that the GEO4 software is a valuable tool for simulating the behavior of bored piles in tropical soils, offering reliable predictions of load-displacement curves and shear force distribution. The study emphasizes the need for site-specific calibration of geotechnical parameters to achieve accurate results and optimize foundation design in complex soil conditions.
Related Resources #
Further reading includes studies on the use of numerical methods for analyzing deep foundations in tropical soils, as well as research on the application of GEO4 software in other geotechnical contexts. Additional resources on soil-pile interaction and load-displacement behavior can provide deeper insights into optimizing foundation design strategies.
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