This paper investigates the friction properties of the soil-geocell interfaces through direct shear tests. The geocells were formed using geogrids in the bottom half of the direct shear box having inside clear plan dimensions of 300 mm ´ 300 mm and depth of top and bottom boxes 110 mm each. Total four types of geogrids were used in different tests. These geocells were filled with granular soil. The upper half of the direct shear box was filled with very soft clay. Some tests were also conducted without the geocells. Results showed that the interfacial friction properties of soil were improved due to the provision of geocells, indicating that the geocells are efficient in preventing possible slip at the interface.
The term geocell refers to cellular form of polymeric material. A network of interconnected geocells filled with soil provides all-round confinement to the soil (Bathurst and Karpurapu, 1995, Rajagopal et al., 1999). Geocells find applications in the construction of embankments over soft soils (Bush et al., 1990, Cowland and Wong, 1993, Krishnaswamy et al., 1998), erosion control, channel protection, etc. Bathurst and Crowe (1992) have reported the results from some direct shear tests conducted on the interface between two geocell layers for designing geocell reinforced retaining walls. These geocells are either manufactured onsite using geosynthetics or obtained readymade and subsequently filled with granular soil to serve different applications. Number of studies reported that a layer of geocells, provided at the base of an embankment constructed on soft soils, acts as an immediate working platform for the construction, promotes uniform settlements, minimises construction time, increases bearing capacity and reduces settlements to a great extent. This paper investigates the interfacial friction properties of various soil-geocell interfaces for designing geocell supported embankments over soft foundation soils.
