Element soil behaviour during pile installation simulated by 2D-DEM

¹ MSc student, Department of Civil, Environment & Geomatic Engineering, University College London, London, UK
² Senior Lecture, Department of Civil, Environment & Geomatic Engineering, University College London, London, UK
³ Academic visitor, Department of Civil, Environment & Geomatic Engineering, University College London, London, UK
Associate Professor, Qingdao Technological University, Qindao, China

^* Xiaohui Ji: xiaohuiji211@163.com

Published online: 30 June 2017

Abstract

The estimation of the skin friction of onshore or offshore piles in sand is still a difficult problem for geotechnical engineers. It has been accepted by many researchers that the mechanism of driving piles in the soil has shared some similarities with that of an element shear test under the constant normal stiffness (CNS) condition. This paper describes the behaviour of an element of soil next to a pile during the process of pile penetration into dense fine sand using the 2D-DEM numerical simulation software. A new CNS servo was added to the horizontal boundary while maintaining the vertical stress constant. This should simulate the soil in a similar manner to that of a CNS pile-soil interface shear test, but allowing the vertical stress to remain constant which is more realistic to the field situation. Shear behaviours observed in these simulations were very similar to the results from previous researchers’ lab shearing tests. With the normal stress and shear stress obtained from the virtual models, the friction angle and the shaft friction factor β mentioned in the API-2007 offshore pile design guideline were calculated and compared with the API recommended values.