DEM modelling of screw pile penetration in loose granular assemblies considering the effect of drilling velocity ratio

Shi, Danda; Yang, Yancheng; Deng, Yibing; Xue, Jianfeng

doi:10.1007/s10035-019-0933-3

Cited by 31 publications

(23 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…AR has a reduced effect on the installation torque with a pronounced effect only at the extremes of under-flighting and self-weight installation, which shows an increase and reduction of torque requirement, respectively (Figure 3b, 3d and 3f). This is in agreement with the DEM study of Shi et al (2019) as well as the 1g physical modelling studies of Shi et al (2018) and Kenny et al (2003), who all noted a large decrease in compressive installation force and a smaller decrease in installation torque when installing at lower AR values. Thus, it would seem there is potential for reducing vertical load (or crowd) requirements during installation by reducing the AR to below the recommended "perfect" or pitch matched installation.…”

Section: Effect Of Ar On Installation Resistancesupporting

confidence: 90%

“…Rather than using a continuum to model the soil, DEM uses discrete particles that have the ability to interact as a soil body. With the application of an increased gravitational field, the DEM is able to act as a virtual centrifuge (Ciantia et al 2018;Sharif, et al 2019a) when properly calibrated (as detailed in Sharif et al (2019a)), with the added benefit of using a single soil bed (particle arrangement) which can be reset and used multiple times (Shi et al 2019).…”

Section: Methods Adopted For Dem Modelling and Pile Detailsmentioning

confidence: 99%

“…This value represents the multiplier applied to the diameter of particles, so that each particle represented n i 3 particles with the bulk properties of the soil remaining the same. This methodology has previously been implemented by McDowell et al (2012) and Shi et al (2019). The particle scaling of 20 was selected based upon the minimum recommended ratio of diameter of the pile core (D c ) to the median particle size (d 50 ) of 2.69 (Arroyo et al 2011).…”

Section: R a F Tmentioning

confidence: 99%

“…If the vertical velocity is greater than v crit a net compression effect below the helices is produced, increasing the vertical installation force and torque. Shi et al (2019) investigated the effect of critical drilling velocity on the installation requirements of multi helix complex screw pile geometries using 1g physical modelling and the Discrete Element Method (DEM). The results of their investigation show that a change in particle displacement and therefore mechanism occurs when installing above and below v crit .…”

Section: Introductionmentioning

confidence: 99%

“…The results of their investigation show that a change in particle displacement and therefore mechanism occurs when installing above and below v crit . Shi et al (2019) showed that it is possible to reduce both the compressive installation force and torque of the screw pile by decreasing the vertical velocity (by 50%) or in other words decreasing the advancement ratio (AR). However, they do not comment on the post installation in-service performance of the installed pile.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Effects of screw pile installation on installation requirements and in-service performance using the discrete element method

et al. 2021

View full text Add to dashboard Cite

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 which 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.

show abstract

Section: Effect Of Ar On Installation Resistancesupporting

confidence: 90%

Section: Methods Adopted For Dem Modelling and Pile Detailsmentioning

confidence: 99%