Finite element study of the influence of pile jetting on load capacity of adjacent piles

Abstract

A recent technique of pile installation of pre-cast piles without noise or vibration is the use of pile jetting. Water jets at high pressures are used to drive the piles that temporarily liquefy the soil thus allowing the pile to penetrate into the ground under their self-weight. This technique is utilized under conditions where control of construction induced vibration is essential, such as amidst existing structures within a city zone. Due to the excessive water velocity introduced in jetting, soil in the immediate neighbourhood is eroded thus creating a narrow water path along which eroded material is brought to the surface. This paper discusses the numerical modeling of the pile jetting process, the lateral extent of the spread of pore pressure zone around the jetted pile and the effect of pile jetting on the vertical load carrying capacity of adjacent piles. Finite element analyses were performed in two phases using ABAQUS. The results from the analyses clearly illustrate the extent of the soil zone influenced by pile jetting and the influence on the load carrying capacity of the adjacent piles.