Analysis of Driven Pile Capacity within Pre-bored Soil
In Louisiana and many other states in the U.S., pre-boring procedures are routine practice for large displacement piles driven through hard/stiff cohesive soils. At present, the analysis and design of pre-bored piles rely primarily on local experiences, since the effects of pre-boring on the driving force as well as on the setup and long-term shaft resistances within the pre-bored zone remain unclear. Due to the high cost and time involved with field instrumentation and testing on pre-bored piles, this numerical study is funded by the Louisiana Department of Transportation and Development (DOTD) as a first step to explore the impacts of pre-bore size on the drivability and long-term shaft resistance reduction of piles. In this research, researchers developed simplified yet realistic numerical model, which considers a thin horizontal soil disc sufficiently far from the ground surface and the pile base using the ABAQUS package to investigate the effects of pre-boring on the pile behaviour over different installation and loading stages. Leveraging on the finite element model developed, the long-term shaft resistance reduction factor curves have been generated for typical Louisiana soil strata to provide guidelines for a better design and construction of pre-bored piles in Louisiana. On the basis of the numerical calculation results, a preliminary protocol, including the site selection, soil properties investigation, and the testing procedure and data collection, is subsequently proposed for future instrumented pile field tests of pre-bored piles in Louisiana. Finally, to facilitate the design of pre-bored piles, a set of practical formulas are developed to predict/evaluate conveniently the driving force, setup and long-term shaft resistances of pre-bored piles. The current research work not only reveals the shaft resistance reduction mechanism of pre-bored piles, but also provides a simple and reliable approach to evaluate the driving force and shaft resistance of pre-bored piles, which will be helpful and beneficial for geotechnical and construction engineers involved with the design and installation of the pre-bored pile foundations in Louisiana.
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- Summary URL:
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Corporate Authors:
Louisiana State University, Baton Rouge
Department of Civil and Environmental Engineering
Baton Rouge, LA United States 70803Louisiana Department of Transportation and Development
Baton Rouge, LA United StatesFederal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC United States 20590 -
Authors:
- Chen, Shengli
- Li, Lin
- Publication Date: 2020-5
Language
- English
Media Info
- Media Type: Digital/other
- Edition: Final Report
- Features: Figures; Maps; References; Tables;
- Pagination: 148p
Subject/Index Terms
- TRT Terms: Boring; Finite element method; Geotechnical engineering; Pile driving
- Geographic Terms: Louisiana
- Subject Areas: Bridges and other structures; Construction; Geotechnology; Highways;
Filing Info
- Accession Number: 01835051
- Record Type: Publication
- Report/Paper Numbers: FHWA/LA.17/623
- Contract Numbers: LTRC Project Number: 18-1GT; SIO Number: DOTLT1000
- Files: NTL, TRIS, ATRI, USDOT, STATEDOT
- Created Date: Jan 31 2022 2:02PM