Abstract: (16347 Views)
Large size direct shear tests (i.e.300 x 300mm) were conducted to investigate the interaction between clay
reinforced with geogrids embedded in thin layers of sand. Test results for the clay, sand, clay-sand, clay-geogrid, sandgeogrid
and clay-sand-geogrid are discussed. Thin layers of sand including 4, 6, 8, 10, 12 and 14mm were used to
increase the interaction between the clay and the geogrids. Effects of sand layer thickness, normal pressure and
transverse geogrid members were studied. All tests were conducted on saturated clay under unconsolidated-undrained
(UU) conditions. Test results indicate that provision of thin layers of high strength sand on both sides of the geogrid
is very effective in improving the strength and deformation behaviour of reinforced clay under UU loading conditions.
Using geogrids embedded in thin layers of sand not only can improve performance of clay backfills but also it can
provide drainage paths preventing pore water pressure generations. For the soil, geogrid and the normal pressures
used, an optimum sand layer thickness of 10mm was determined which proved to be independent of the magnitude of
the normal pressure used. Effect of sand layers combined with the geogrid reinforcement increased with increase in
normal pressures. The improvement was more pronounced at higher normal pressures. Total shear resistance provided
by the geogrids with transverse members removed was approximately 10% lower than shear resistance of geogrids
with transverse members.
Type of Study:
Research Paper |