Monitoring and analysis of the bending behaviour of discrete piles used to stabilise a railway embankment

Abstract

Discrete piles are used to stabilise infrastructure slopes, especially where there is insufficient additional land to allow construction of large toe berms or regrading of the slope. Compared with more conventional structures such as retaining walls, there are few field data on how discrete piles typically bend and displace under slope loading. This paper presents the results from monitoring a number of discrete piles used to stabilise a railway embankment at Hildenborough, Kent, UK. Bending deflections deduced from strain gauges are compared with the displacements and rotations measured by inclinometer tubes cast into the piles. Four years after pile installation, the piles were bending downslope over their lower halves, with little bending measured in the upper sections. Regrading of the rockfill piling platform shortly after pile construction caused some of the pile loading, with further loading caused by the continued tendency for slope movement. Analysis of the piles using a simple elastic analysis gives bending moments and displacements close to those measured. Discrete piles are used to stabilise infrastructure slopes, especially where there is insufficient additional land to allow construction of large toe berms or regrading of the slope. Compared with more conventional structures such as retaining walls, there are few field data on how discrete piles typically bend and displace under slope loading. This paper presents the results from monitoring a number of discrete piles used to stabilise a railway embankment at Hildenborough, Kent, UK. Bending deflections deduced from strain gauges are compared with the displacements and rotations measured by inclinometer tubes cast into the piles. Four years after pile installation, the piles were bending downslope over their lower halves, with little bending measured in the upper sections. Regrading of the rockfill piling platform shortly after pile construction caused some of the pile loading, with further loading caused by the continued tendency for slope movement. Analysis of the piles using a simple elastic analysis gives bending moments and displacements close to those measured.