The Technology of Multilayer Mechanical Stabilization of the Railway Ballast by Flat Polymer Geogrids

Abstract

The problem of railway ballast degradation during service life is receiving considerable attention. The primary reason of aggregate particles cracking and abrasion is the maintenance operation of machine ballast tamping. Reduction of tamping operations frequency helps to maintain the quality of crushed stone and therefore, reduce the deformation of ballast. This may be achieved by increasing aggregate stiffness by mechanical stabilisation with flat rigid polymer geogrid. Laboratory modeling of cyclic loaded ballast shows that one layer of geogrid at the bottom of ballast reduces the settlement by 34 % while multilayer stabilisation by 3 geogrids reduces it by 67 % and possibly allows avoiding tapping during service life. As an alternative maintenance option, the authors propose bedding with pneumatic stone blowing or shallow tapping to the depth of 70 mm.