Effects of screw pile installation on installation requirements and in-service performance using the Discrete Element Method

TY - JOUR

T1 - Effects of screw pile installation on installation requirements and in-service performance using the Discrete Element Method

AU - Sharif, Yaseen Umar

AU - Brown, Michael John

AU - Cerfontaine, Benjamin

AU - Davidson, Craig

AU - Ciantia, Matteo Oryem

AU - Knappett, Jonathan Adam

AU - Brennan, Andrew

AU - Ball, Jonathan David

AU - Augarde, Charles

AU - Coombs, William M.

AU - Blake, Anthony

AU - Richards, David

AU - White, David

AU - Huisman, Marco

AU - Ottolini, Marius

N1 - Funding Information: This research is a part of an EPSRC NPIF funded studentship with Roger Bullivant Limited (Grant No. EP/R512473/1). The third author is supported by the European Union?s Horizon 2020 research and innovation programme under the Marie Sk?odowska?Curie grant (Agreement No. 753156). The authors would also like to acknowledge the support of EPSRC: Supergen Wind Hub: Grand Challenges Project: Screw piles for wind energy foundations (Grant No. EP/N006054/1) for the impetus for this study. Publisher Copyright: © Canadian Science Publishing. All rights reserved.

PY - 2021/9

Y1 - 2021/9

N2 - Existing guidance on the installation of screw piles suggest that they should be installed in a pitch-matched manner to avoid disturbance to the soil that may have a detrimental effect on the in-service performance of the pile. Recent insights from centrifuge modelling have shown that installing screw piles in this way requires large vertical compressive (or crowd) forces, which is inconsistent with the common assumption that screw piles pull themselves into the ground requiring minimal vertical compressive force. In this paper, through the use of the discrete element method (DEM), the effects of advancement ratio, i.e., the ratio between the vertical displacement per rotation to the geometric pitch of the helix of the screw pile helix, on the installation resistance and in-service capacity of a screw pile is investigated. The findings are further used to assess the applicability of empirical torque capacity correlation factors for large diameter screw piles. The results of the investigation show that it is possible to reduce the required vertical compressive installation force by 96% by reducing the advancement ratio and that although over-flighting a screw pile can decrease the subsequent compressive capacity, it appears to increase the tensile capacity significantly.

AB - Existing guidance on the installation of screw piles suggest that they should be installed in a pitch-matched manner to avoid disturbance to the soil that may have a detrimental effect on the in-service performance of the pile. Recent insights from centrifuge modelling have shown that installing screw piles in this way requires large vertical compressive (or crowd) forces, which is inconsistent with the common assumption that screw piles pull themselves into the ground requiring minimal vertical compressive force. In this paper, through the use of the discrete element method (DEM), the effects of advancement ratio, i.e., the ratio between the vertical displacement per rotation to the geometric pitch of the helix of the screw pile helix, on the installation resistance and in-service capacity of a screw pile is investigated. The findings are further used to assess the applicability of empirical torque capacity correlation factors for large diameter screw piles. The results of the investigation show that it is possible to reduce the required vertical compressive installation force by 96% by reducing the advancement ratio and that although over-flighting a screw pile can decrease the subsequent compressive capacity, it appears to increase the tensile capacity significantly.

KW - Installation Effects

KW - Screw Piles

KW - Discrete element method

KW - Silent Piling

KW - Installation effects

KW - Discrete element method (DEM)

KW - Screw piles

UR - https://www.scopus.com/pages/publications/85113273911

U2 - 10.1139/cgj-2020-0241

DO - 10.1139/cgj-2020-0241

M3 - Article

SN - 0008-3674

VL - 58

SP - 1334

EP - 1350

JO - Canadian Geotechnical Journal

JF - Canadian Geotechnical Journal

IS - 9

T2 - 1st International Symposium on Screw Piles for Energy Applications

Y2 - 27 May 2019 through 28 May 2019

ER -