Simulation of the Plug inside Open Steel Pipe Piles with Regards to Different Installation Methods

Abstract

Open steel pipe piles are used for various applications in costal engineering and port structures and they are becoming increasingly more important for offshore structures. A plug formed during the installation of open steel pipe piles has an influence on the installation process of the steel pipe pile as well as on the final bearing behaviour and the pile resistance. Forming of the plug depends on different influences, e.g. the pile diameter, the soil conditions and the installation method. To obtain a better understanding of the formation of the plug and its consequences several experimental small-scale tests, experimental field tests and numerical simulations have been performed. But so far this phenomenon is not completely investigated yet. At the beginning of this paper a structured overview about the characterization of the plug as well as soil mechanical processes during the pile installation in non-cohesive soil are provided. Then, the results of a centrifuge study are shown. The focus of this paper is the numerical simulation of the installation process of impact and vibratory driven piles in non-cohesive soil to investigate the effect of plugging with regard to different installation methods. Centrifuge experimental results are utilized to validate the numerical model, which can provide detailed insights into the physical processes occurring in the soil but are difficult to measure in experiments. The numerical analyses hence illustrate zones of densification/loosening, which highlight the differences resulting from the installation methods.

Centrifuge study on effect of installation method on lateral response of monopiles in sand

“…In the majority of published tests, the monopiles were installed by jacking at 1g, although Centrifuge experimental study on the effect of the installation method… Fan, Bienen, Randolph _____________________________________________________________________________________ 4 it is known that the state of the surrounding soil is significantly influenced by the pile installation method (Henke and Bienen, 2013;Labenski et al, 2016). As a result, the subsequent lateral response of monopile may be affected.…”

Effects of Monopile Installation on Subsequent Lateral Response in Sand. I: Pile Installation

“…Both pile jacking and impact driving lead to significant changes in void ratio, as also noted by a number of researchers (Heins et al 2018;Henke and Grabe, 2008;Labenski et al 2016;Lundberg, 2015;Phuong et al 2016). The differences in the changes in void ratio are significant between pile jacking and impact driving as shown in Figure 7, Figure 9 and Figure 11 for sand at different relative densities.…”

“…Figure 16 shows the maximum horizontal stress reported inside and outside the pile following pile jacking and impact driving in sand at different relative densities. However, the degree of the increase in the horizontal stress in jacked piles is significantly higher than in impact-driven piles, as also noted by Henke and Grabe (2008) and Labenski et al (2016). Impact driving leads to an increase in the horizontal stress in the region below the pile tip.…”

“…This emphasises the need to understand the effect of pile installation on the surrounding soil. Labenski et al (2016) and Phuong et al (2016) demonstrate the possibility of revealing changes in soil states numerically. Numerical results indicate the soil is significantly affected by the installation process, with marked differences in the degree of disturbance from different installation methods.…”

Experiment Investigation on Stress Characteristics of Grouting Microsteel Pipe Piles with Cement‐Soil Wall

“…In recent years, microsteel pipe piles have widely been used in slope support, and few studies have been applied to foundation pit support. Labenski and Moormann proposed a simple numerical analysis method to simulate the mechanical characteristics of the microtube piles in the process of pile jacking and proposed that the soil density around the pile has a greater influence on the lateral bearing capacity of the steel pipe piles [7]. Hazarika et al explored the influence of different piled pile angles on the support effect of the microsteel pipe piles in the slope support and confirmed that changing the position of the pile can effectively improve the support effect.…”