Abstract:
In urban areas, excavations for cut-and-cover tunnels and basement construction cause detrimental
effects on adjacent piles. This paper presents a case study of a deep excavation carried out adjacent
to a group of piles consisting of 22 m long step tapered piles. The pile group was located 0.6 m behind
a temporary sheet pile wall. The excavation was primarily carried out through the layered sandy soils
and supported by a sheet pile. The retaining wall system of the 15 m deep excavation was supported
by tie back anchors at three levels. Finite element modelling is used to simulate the staged
construction sequence, which involves excavation and installation of the prop system. Constitutive
behaviour of the soil is modelled using an elasto-plastic model due to the limited amount of material
properties available for the site. The pile deflection and the soil movements from two and three
dimensional finite element analyses are compared with field data to determine the most appropriate
way of modelling the pile group behaviour adjacent to an excavation.
