Rapid urban development in the hilly terrain of Hong Kong involves the construction of high-rise buildings, many of which are supported on large diameter bored piles. These piles may sometimes have to be founded in slopes and have to resist severe wind loads during typhoon season. In order to minimise the transfer of lateral load from the buildings to the shallow depths of the slopes, an annulus of compressible material (referred to as sleeving) has sometimes been incorporated between the piles and the adjacent soils. In this paper, three-dimensional (3D) numerical analyses were carried out to examine the interactive effects of sleeved piles on slope stability. In the case of a single pile in a slope with a respectable safety margin, the sleeving technique is shown to be capable of minimising the adverse impact of lateral pile loading on local slope instability compared to an unsleeved pile, particularly under high lateral loading. In the case of a marginally stable slope which is vulnerable to external loading, whether the single pile is sleeved or not would make little difference to the global factor of safety.
Rapid urban development in the hilly terrain of Hong Kong involves the construction of high-rise buildings, many of which are supported on large diameter bored piles. These tall buildings have to resist severe wind loads during the typhoon season each year. Local instability may be associated with the initiation of plastic deformation at the shallow ground in front of the laterally loaded pile, with development of successive cracks being likely to occur in sand (Uto et al., 1985), and large plastic deformation being likely to occur in clay. Global failure may occur if the soil mass supporting the pile develops a slip surface, accompanied by uncontrolled large displacements.
