INFLUENCE OF LATERALLY LOADED SLEEVED PILES ON
SLOPE STABILITY
C.W.W. Ng1, L.M. Zhang1, K.K.S. Ho2, and C.K. Choy1
ABSTRACT
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.
INTRODUCTION
