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Analytical model of skin friction for bored pile socketed into weak rocks in ice-rich permafrost regions.

Authors :
Zhang, Chaoyang
Jiang, Chong
Pang, Li
Chen, Lujie
Source :
Cold Regions Science & Technology. Aug2023, Vol. 212, pN.PAG-N.PAG. 1p.
Publication Year :
2023

Abstract

Bored piles constructed in permafrost regions often need to be socketed into weak and weathered rock strata, such as marl stratum. When these strata are ice-rich, the meltwater caused by construction will form an ice film at the pile-rock interface during refreezing, leading to a reduction in pile bearing capacity. By analyzing the shear mechanism of pile-rock interface with ice film, an interface shear model was proposed in this paper. Based on this model, the load transfer analytical method of rock-socketed bored piles was improved. Finally, the effects of pile-rock interface roughness, ice filling degree, and residual friction angle on skin friction were analyzed. The results show that the shear stress-displacement curve of the ice-containing interface unit exhibits two peaks and can be divided into four stages: ice film shear stage, ice film extrusion stage, concrete-rock relative sliding stage, and interface residual sliding stage. Increasing either the dilation angle or half-wavelength can improve the interface's shear resistance when only one variable is altered. Furthermore, the peak shear strength of the interface decreases as the filling degree increases. The interface residual shear stress is positively correlated with both the residual friction angle of weak rock (ϕ u − r) and ice (ϕ i − r), and increasing the proportion of ice in the residual sliding surface will lead to the reduction of residual shear stress. • In the presence of ice interlayer at pile-rock interface, the shear process can be divided into four stages. • The calculation model of skin friction for rock-socketed piles in ice-rich permafrost regions was improved. • The effects of interface roughness, ice filling degree, and residual friction angle on skin friction were analyzed. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
0165232X
Volume :
212
Database :
Academic Search Index
Journal :
Cold Regions Science & Technology
Publication Type :
Academic Journal
Accession number :
164018968
Full Text :
https://doi.org/10.1016/j.coldregions.2023.103886