Micromechanics of Pile Cyclic Response in Sand

TY - GEN

T1 - Micromechanics of Pile Cyclic Response in Sand

AU - Ciantia, Matteo

N1 - Conference code: 16th

PY - 2021

Y1 - 2021

N2 - A 3D discrete element model is used to investigate the axial cyclic response of a small-scale displacement piles installed in Fontainebleau sand. Calibration chamber experimental results from literature are used to validate the pile penetration phase of the DEM model which is then employed to simulate stress controlled vertical cyclic loading. The crushable DEM particle model is calibrated using high pressure element test data for the same sand. The model predicts the experimental stress measurements surrounding the jacked pile in both penetrating and unloaded conditions. The DEM model is used to assess micromechanical features hard to detect using experimental and continuum numerical methods. Grain crushing within the soil is observed to occur only below the cone during pile penetration. The analysis of particle stresses and force chains highlight how arching develops around the shaft. These arching effects create a sort of shield around the shaft causing the radial stresses to be lower. After pile installation is completed, a numerical parametric study of stress controlled cyclic axial loading of the pile is performed. The results show that depending on the magnitude of the cyclic load stable or metastable pile cyclic response is attained. The cyclic load amplitude also influences in different ways both stress and density profiles around the pile. These results may serve as a step forward to the understanding of installation effects on axial cyclic performance of jacked piles in sand.

AB - A 3D discrete element model is used to investigate the axial cyclic response of a small-scale displacement piles installed in Fontainebleau sand. Calibration chamber experimental results from literature are used to validate the pile penetration phase of the DEM model which is then employed to simulate stress controlled vertical cyclic loading. The crushable DEM particle model is calibrated using high pressure element test data for the same sand. The model predicts the experimental stress measurements surrounding the jacked pile in both penetrating and unloaded conditions. The DEM model is used to assess micromechanical features hard to detect using experimental and continuum numerical methods. Grain crushing within the soil is observed to occur only below the cone during pile penetration. The analysis of particle stresses and force chains highlight how arching develops around the shaft. These arching effects create a sort of shield around the shaft causing the radial stresses to be lower. After pile installation is completed, a numerical parametric study of stress controlled cyclic axial loading of the pile is performed. The results show that depending on the magnitude of the cyclic load stable or metastable pile cyclic response is attained. The cyclic load amplitude also influences in different ways both stress and density profiles around the pile. These results may serve as a step forward to the understanding of installation effects on axial cyclic performance of jacked piles in sand.

KW - Crushing

KW - Cyclic loading

KW - DEM

KW - Piles

KW - Sands

KW - Setup

UR - https://www.scopus.com/pages/publications/85101579614

U2 - 10.1007/978-3-030-64518-2_62

DO - 10.1007/978-3-030-64518-2_62

M3 - Conference contribution

SN - 9783030645175

VL - 2

T3 - Lecture Notes in Civil Engineering

SP - 527

EP - 535

BT - Challenges and Innovations in Geomechanics

A2 - Barla, Marco

A2 - Di Donna, Alice

A2 - Sterpi, Donatella

PB - Springer

CY - Switzerland

T2 - 16th International Conference of the International Association for Computer Methods and Advances in Geomechanics

Y2 - 1 July 2020 through 3 July 2020

ER -