Open AccessPile Side Resistance in Sands for the Unloading Effect and Modulus Degradation
Author(s) -
Chunfeng Zhao,
Yue Wu,
Cheng Zhao,
Q. Z. Zhang,
F. M. Liu,
F. Liu
Publication year - 2019
Publication title -
materiales de construcción
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.539
H-Index - 30
eISSN - 1988-3226
pISSN - 0465-2746
DOI - 10.3989/mc.2019.03718
Subject(s) - dilatant , direct shear test , shear modulus , materials science , pile , geotechnical engineering , surface finish , shear stress , shear (geology) , modulus , composite material , surface roughness , elastic modulus , hydraulic roughness , geology
A total of 36 groups of sand-concrete interface loading and unloading direct shear tests were used to analyze the mechanical properties of the pile side-soil interface. The test results show that the interface residual shear stress for the same applied normal stress tends to be constant for the rough sand-concrete interface. The initial shear modulus and peak shear stress of the interface both decrease with the degree of unloading and increase with the interface roughness. The maximum amount of interface shear dilatancy increases with the degree of unloading, and the maximum amount of interface shear shrinkage decreases with unloading for the same interface roughness. A pile side resistance-displacement model is established using the shear displacement method. The proposed function considers both the radial unloading effect and modulus degradation of soil around the pile. The effect of radial unloading and interface roughness on the degradation of the equivalent shear modulus is analyzed using a single fitting parameter b. Good agreement of the proposed model is confirmed by applying the direct shear tests of the 36 groups.