Experimental evaluation of water infiltration through concrete-geocell liners

In this article we study the infiltration rate and flow characteristics of water through concrete-geocell liners by experimental and analytical means. Geocells filled with concrete have been used in the construction of many hydraulic works, such as shore protections (both marine and riverine), spillways, and canal liners; these liners have been reported to offer high performance, as they are able to withstand large flow velocities, hydrodynamic effects, and environmental stresses, while still being more cost-effective than other hard-armor systems such as reinforced concrete and articulating concrete blocks (ACBs). Despite their increasing use there is no report of their hydraulic conductivity in the literature, which this paper aims to fulfil. First, an analytical solution to the problem is achieved by parting from the incompressible Navier-Stokes equations and applying reasonable assumptions to arrive at a formula that relates flow rate to pressure gradient, fluid properties, and importantly, the hydraulic aperture (the idealized gap at the concrete-geocell interface); this gap is then estimated using the ACI-209 method for the prediction of concrete shrinkage, resulting in the proposed semi-analytical method. The formulation was then evaluated experimentally by conducting hydraulic tests on full scale geocell specimens filled with concrete under conditions that are deemed representative of real case applications. The results indicate that the proposed methodology has satisfactory predictive capabilities and provides flow rate estimates in accordance with measured data.