Numerical simulation of plug formation during casing installation of cast-in-place concrete pipe (PCC) piles

Abstract

There is a historic lack of research examining inner soil plugging and outer lateral soil deformation during installation of pipe piles in clay. Furthermore, the influence of the pile tip geometry on soil deformation has not been investigated. Cast-in-place concrete pipe (PCC) piles are a recent generation of pipe piles for soft ground improvement applications, and are cast in place using an innovative double-walled steel casing with a tapered tip. This paper investigates the effect of tip geometry on soil flow mechanisms inside and outside the PCC pile casing during installation in clay. Large-deformation finite element (LDFE) analysis was conducted simulating the continuous penetration process of the casing installation. The LDFE results were validated against (i) field monitoring data in terms of soil lateral displacement and heave outside the casing and (ii) centrifuge test data in terms of penetration resistance, with excellent agreement obtained. An extensive parametric study was then performed encompassing a practical range of parameters. The geometry of the casing tip was shown to have significant influence on the soil movements inside and outside the casing, but minimal effect on the casing penetration resistance. The optimal tapered tip with a tip angle of 45° and minimal extended tip length beneath the tip angle allowed more soil to be pushed inside the casing and less lateral displacement outside the casing, which dictates the amount of concrete required to fill the cavity inside the pile and the pile construction sequence, respectively. Design expressions are proposed for estimating soil movements inside and outside the casing with optimal tip geometry being installed.

A new approach for longitudinal vibration of a large-diameter floating pipe pile in visco-elastic soil considering the three-dimensional wave effects

“…(6) The proposed analytical approach in this paper is suitable for PCC piles [44] where the inner pipe is fully plugged [33,[45][46][47].…”

A novel analytical approach to vertical dynamic vibration of pipe‐pile groups considering soil‐plug effect

“…25 Li et al 26 and Zheng et al 27 investigated the influence of inner soil on the vertical dynamic response of a single pipe pile. The primary focus of the existing research concentrated on the improvement of the analytical models for pipe piles, surrounding soil, and inner soil [28][29][30][31][32] by assuming that the height of the inner soil is the same as that of the pipe pile. Owing to this assumption, these methods cannot consider the influence of different heights of the inner soil, known as the soil-plug effect, on the dynamic response of the pipe pile.…”

Numerical and Experimental Study on Soil Plug Resistance of Open‐Ended Pipe Pile with a Restriction Plate

“…Researchers have proposed different mathematical models to study the bearing capacity and settlement behavior of open-ended pipe piles under various loading conditions [30][31][32][33]. Numerical methods, for example, finite element method and coupled Eulerian-Lagrangian numerical technique, are used to study the mechanical behavior of LDOEPPs [34,35]. e discrete element method (DEM) proposed by Cundall and Strack [36] is found advantageous, especially in the simulation of soil arching inside the pipe pile [37,38].…”