Ground Disturbance Due to Static Pressure Driving of Opened-Ended PHC Piles-Paper

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The study examines ground disturbance caused by installing 52 open-ended prestressed high-strength concrete (PHC) piles beside an existing highway embankment in China. Field instruments measured excess pore-water pressure and lateral soil movement during and after pile driving.<br /><br />Excess pore pressure generally increased with depth and decreased with distance from the piles, with effects detectable as far as 43 pile diameters away. Within the pile area, peak excess pressures averaged about 85% of effective overburden pressure. Dissipation was slow in the clayey soils: an average of 79% had dissipated after 20 days. The greatest pressures occurred at depth and close to the pile group.<br /><br />Lateral displacement also declined with distance from the piles and was influenced by soil properties; soils with higher water content and void ratio were more deformable. Displacement could continue to develop after driving, so movements from earlier piles may accumulate during installation of later ones. This creates a risk of pile movement or inclination if installation proceeds too quickly or piles are closely spaced. Ground movement became very small at distances of roughly three pile spacings.<br /><br />The existing embankment’s loading and denser foundation soil limited lateral movement toward the road. Measurements indicated that the pile installation had negligible overall effect on the existing road. The authors emphasize monitoring pore pressure and displacement, and planning pile sequence and timing to manage delayed ground movement.

Keywords

PHC piles

pile driving

excess pore pressure

lateral soil movement

ground disturbance

highway embankment

clayey soils

pore-water pressure dissipation

pile installation monitoring

soil deformation