Geosynthetics JUNE/JULY 2021 Volume 39 Number 3 12 ON THE COVER Geocell installation above the existing subgrade Features 12 NPA geocell for a railway line repair in a permafrost region By Sanat Pokharel and Marc Breault 22 Design of reinforcement geosynthetics in landfill piggyback expansion By Jean-Baptiste Duquet, Cédric Sarbach and Stephan Fourmont 32 Dewatering of sludge from a sewage treatment plant with geotextile tubes By M. Müller, E. A. Guanaes, D. Vidal and M. R. Freitas 22 32 www.GeosyntheticsMagazine.com 3http://www.GeosyntheticsMagazine.com