An analytical model for the interaction between two dissimilar piles in a finite soil layer

• Published in: International journal for numerical and analytical methods in geomechanics Vol. 45; no. 7; pp. 950 - 964
• Main Authors: Liu, Huan, Liu, Qijian
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 01-05-2021
• Subjects: Addition theorem; Boundary value problems; Constants; Coordinate systems; Coordinates; Graf's addition theorem; interaction factor; Interfaces; KEYWORDS dissimilar piles; modulus function; Piles; Soil; Soil analysis; Soil investigations; Soil layers; Soil properties; Soils; Step functions; vertical loadings; Vertical loads
• ISSN: 0363-9061; 1096-9853
• DOI: 10.1002/nag.3187

An analytical method is developed for the interaction between two dissimilar piles subjected to vertical loadings in a finite soil layer with a rigid base. A fictitious soil column is assumed for the corresponding shaft and the moduli of the soil–pile rod are expressed as a Heaviside step function of the modulus. The vertical soil displacements and the shaft resistances are calculated as the combined contributions by the two dissimilar piles in terms of the respective local coordinate systems. The displacements and stresses in two different local coordinates are transferred from one to the other using Graf's addition theorem. The boundary value problem for the soil layer is solved using the method of separation of variables with a series of undetermined constants. The unknown constants can be determined by considering the compatibility along the interfaces of the two soil–pile rods and the surrounding soil. A parametric study is performed to investigate the effects of the properties of the soil–pile system on the interaction between the two piles. Numerical results show that, for the dissimilar piles in the stiff soil, the effects of the difference of the pile lengths on the interaction factor are negligible. Also, the interaction factor of the dissimilar piles in the soft soil depends heavily on the difference in lengths.