As an alternative to a 60 cm thick compacted cohesive soil, the approximately 10 mm thick Bentofix® geosynthetic clay liner, manufactured with high swelling natural sodium bentonite, is used. The robust cover and carrier geotextiles used in the construction of Bentofix® are designed to withstand rough installation loads. Bentofix® is uniformly manufactured with direction-independent needlepunching (fibre reinforcement) over its entire surface area, with more than 2 million fibres per square metre. Depending on the existing soil conditions and slope lengths, slope inclinations of 2.5h:1v or greater are possible, due to the surface structure of the needlepunched cover and carrier geotextiles and the large internal friction angle. In poor soil conditions or on steeper slopes, Secugrid® geogrid can be used to further ensure slope stability.
Due to their thin profile, Bentofix® geosynthetic clay liners consume less airspace than compacted clay, and can require less soil excavation and removal. The Bentofix® BFG 5000 features a cover geotextile that has been uniformly impregnated with bentonite powder over it entire surface area. This bentonite treatment in the cover geotextile can make the installation more efficient as the field application of bentonite paste to the overlaps is not required.
The Bentofix® encapsulating geotextiles are typically made from polypropylene (PP) resin and therefore sufficiently resistant to a wide range of conventional chemicals, such as diesel fuel, oil and benzene. In cases where aggressive chemicals may be encountered, the Bentofix® geotextiles can be manufactured with high density polyethylene (HDPE). Alternatively, 2.0 mm thick Carbofol® HDPE geomembranes can be installed. Carbofol® HDPE geomembranes are best suited to aggressive conditions due to their wide range of chemical and natural element resistance (e. g. to UV-radiation, rodents, chemicals). Not only is placement easy, it is also easy to weld Carbofol® HDPE geomembranes due to the favorable Melt Flow Index of the base resin.
Structured and Friction Carbofol® geomembranes are available to effectively transfer shear forces on the most challenging slope locations. Regardless, project specific direct shear tests should be performed to verify the required shear strength parameters are being met by the components selected for use.