Geocell-reinforced bed anchored with additional vertical elements under repeated loading

Abstract

This paper investigates the behavior of geocell-reinforced beds combined with extra vertical elements embedded into the geocell pockets at their joints. During repeated loading, the soil mass inside geocell pockets can loosen, leading to decrease in geocell layer extension. Vertical elements can help to reduce the soil loosening, alleviate deformation and distortion of the geocell wall directly under loading zone and provide anchorage at the geocell outer boundaries. Results show that, with the use of vertical elements, geocell performance is significantly enhanced due to better load distribution and extra anchorage. An average 40% reduction in cyclic settlement was observed using combined geocell and vertical elements compared with a bed reinforced with geocell alone. Also, with an optimum height of the vertical elements, a 42% reduction in geocell consumption even at higher performance can be achieved using a less extensive geocell mattress. Provision of vertical elements caused the geocell length on each side of the footing to be decreased from 1.1D to 0.5D for the same performance in some cases (D: footing diameter). Prototype experiments showed that the geocell reinforcement anchored with vertical elements experiences less deformation, distributing load over a wider area. Thus, geocell and vertical elements combine to act like a geocell with greater thickness and larger width, helping project economy by lower use of geocell material even if the additional cost of vertical elements may counteract. Calibrated numerical modelling compared favorably with experimental observations, providing insight into stress and strain distribution in the soil and geocell.