Axial Load Transfer Analyses of Energy Piles at a Rock Site
- PDF / 1,715,219 Bytes
- 23 Pages / 547.087 x 737.008 pts Page_size
- 47 Downloads / 179 Views
(0123456789().,-volV) ( 01234567 89().,-volV)
ORIGINAL PAPER
Axial Load Transfer Analyses of Energy Piles at a Rock Site Aria Moradshahi . Ali Khosravi . John S. McCartney
. Abdelmalek Bouazza
Received: 24 November 2019 / Accepted: 21 April 2020 Springer Nature Switzerland AG 2020
Abstract An axial load-transfer analysis for energy piles is presented in this study that incorporates empirical models for estimating the side shear resistance and end bearing capacity in rock along with associated normalized stress-displacement curves. The analysis was calibrated using results from field experiments involving monotonic heating of three 15.2 m-long energy piles in sandstone. Analyses of the field experiments indicates that poor cleanout of the excavations led to an end restraint smaller than that expected for a clean excavation in sandstone. Specifically, end bearing parameters representative of cohesionless sand were necessary to match the loadA. Moradshahi A. Bouazza Department of Civil Engineering, Monash University, Clayton, VIC 3800, Australia e-mail: [email protected] A. Bouazza e-mail: [email protected] A. Khosravi Department of Civil and Construction Engineering, Oregon State University, Corvallis, OR, USA e-mail: [email protected] A. Khosravi Department of Civil Engineering, Sharif University of Technology, Tehran, Iran J. S. McCartney (&) Department of Structural Engineering, University of California San Diego, La Jolla, CA, USA e-mail: [email protected]
transfer analysis to the field experiment results. Parametric evaluations demonstrate the importance of using appropriate rock- or soil-specific empirical models when estimating the side shear resistance and end bearing capacity of energy piles. Specifically, the end bearing capacity and side shear resistance in rock are greater than in soils, leading to more restraint and greater thermal axial stresses. The stiffer side shear restraint in rock was also found to lead to a less nonlinear distribution in thermal axial stress along the length of the energy pile. Keywords Energy piles Load transfer analysis Thermo-mechanical loading Rock behavior List of symbols E Young’s modulus of the energy pile a Linear thermal expansion coefficient of the energy pile ea,M Mechanical axial strain of the energy pile ea,T Thermal axial strain of the energy pile ra Axial stress Ki Stiffness of the energy pile l Length of each element of the energy pile Qb,max End bearing capacity of the energy pile Qs,max Side shear resistance of the energy pile Qbase Reaction force at the base of the energy pile qib,M Displacement at the bottom of each element due to mechanical loading
123
Geotech Geol Eng
qit,M qis,M Qit,M Qib,M Qis,M Qiave DiM DiT qib,T qit,T qis,T Qit,T Qib,T Qis,T riT Qbase,T Qh,T DiT,actual W qu
Displacement at the top of each element due to mechanical loading Displacement at the side of each element due to mechanical loading Mechanical axial force at the top of the energy pile for each element Mechanical axial force at the bo
Data Loading...
