INTERACTION OF LATERITIC SOIL AND STEEL GRID REINFORCEMENT

Laboratory and field pullout tests were carried out to study the inter action of welded steel grid reinforcements embedded in lateritic resid ual soil backfill. The laboratory pullout tests were conducted on vari ous reinforcement sizes, mesh geometries, normal pressures, and compac tion conditions of the backfill material. Field pullout tests were con ducted at representative overburden, field-moisture, and density condi tions. From the test results, it was found that the longitudinal membe rs yielded frictional resistance from 8 to 15% of the total grid pullo ut resistance. Thus, the major contribution to the pullout resistance of grid reinforcements consists of the passive resistance mobilized in front of the transverse members. The maximum pullout resistance is sh own by a bilinear curve which displayed similarity with the failure en velope from direct shear tests of the backfill material. This bilinear envelope reinforced the previous observation regarding the effect of particle breakage phenomenon inherent to lateritic residual soils subj ected to high normal pressures. Comparisons between laboratory and fie ld pullout resistances and between the predicted passive resistance an d the laboratory test data are also presented.