A numerical approach to estimate shaft friction of bored piles in sands

Abstract

A new approach to estimate shaft capacity of bored piles in sandy soils, based on numerical analysis, is presented. The topic is relevant as current design methods often largely underestimate the shaft capacity of piles in sands, thus resulting in an over-conservative design. The proposed approach is based on explicitly modelling the thin cylinder of soil surrounding the pile, where strain localization concentrates (shear band), and on the fundamental mechanic behaviour of sandy soils (e.g. dilatancy, softening). This approach is both simple and easy to apply. Results of a broad parametric study involving axially loaded single piles embedded in different sandy soils are presented, highlighting that relative density and grain size distribution mainly affect the shaft capacity. The capability of the procedure to predict shaft friction is checked against data from a well-documented full-scale axial load test on instrumented pile. Some suggestions for calibration and application of the method are also reported. © 2014 Springer-Verlag Berlin Heidelberg

A Contact Model Coupling Friction and Adhesion: Application to Pile/Soil Interface

“…This process generates stresses and deformations in the surrounding soil in contact. The volume of moved soil is equal to the volume of driven pile [54], [56], [57]. This initial soil stress is important and determines the final solution.…”

“…Under the confinement effect, resulting from the pile installation, a normal contact reaction Rn is generated at the interface [57]- [59] and the sliding limit is ( force ( t R ) is smaller than this limit, the contact nodes forming the interface have a status of contact with sticking expressed by the relation Eq. 15.…”

Shaft Resistance of Piles Close to Backfilled Sand Columns

“…There are many previous studies on the shaft resistance of piles. The previous studies include investigations of the friction between the pile material and soil [10][11][12], the peak strength and dilation of sand-steel interfaces [13], a numerical approach to estimate shaft friction considering dilatancy and strain softening of piles in sand deposits [14], a numerical simulation considering the cross-anisotropy and intermediate principal stress for evaluating shaft resistance of piles installed in sand [15], and a numerical parametric study using distinct element modelling (DEM) to investigate shearing mechanisms at pile-soil interfaces [16]. However, no prior research has considered a case where the backfilled material approaches part of the ground around the new pile.…”

Determination of Young Elasticity Modulus in Bored Piles Through the Global Strain Extensometer Sensors and Real-Time Monitoring Data

“…2019, 9, Few more studies have been performed on longitude strain, which have measured the instrumented piles [8][9][10][11][12][13], transferring of load in rapid pile axial loading [14], static, dynamic, seismic, and cyclic lateral load of pile classifications [15][16][17], rigid and flexible pile behaviors in diverse soft soils [18][19][20], and skin friction resistance measurement in piles [21]. Some studies have been conducted based on numerical simulations, however, others have been performed on field monitoring (Ng and Sritharan [22]; Hung et al [23]; Tafreshi et al [24]; Mascarucci et al [25]; and Lee et al [26]). Ochiai et al [27] propose a reliable designing model for bored-piles following in-situ tests by SPT.…”