Naslov
Effect of transverse ribs of geogrids on pullout resistance

Autori
Mulabdić, Mensur ; Minažek, Krunoslav

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Proceedings 9th International Geosynthetics Conference / E.M.Palmeira - Guarujá : International Geosythetics Society, 2010, 743-746

Skup
9th International Conference on Geosynthetics

Mjesto i datum
Guarujá, Brazil, 25.05.2010. - 28.05.2010

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
pullout test ; interaction ; transversal ribs ; wave ; velocity

Sažetak
A specially equipped pullout apparatus, measuring 1.9 x 0.9 x 1.2 m, has been developed to measure the soil-grid interaction during pullout. The purpose of the testing is to explore the nature of the soil-grid interaction in such a way to enable a more efficient design of reinforced soil in unbound materials. This interaction is characterized by the velocity of waves travelling through the reinforced soil in perpendicular direction towards the grid. The shear and elastic moduli of soil can be calculated based on these velocities, determined at different distances from the grid. Several grids, for different types of soil, were tested in the pullout apparatus, and the wave velocity was measured at different displacement rates. Specially adopted accelerometers were used to determine the arriving time of compressive and shear waves when propagating through reinforced soil, at different vertical distances from the reinforcing grid. The level of interaction can be defined by using the velocity profile or the modulus profile around the grid, taking into account the change of maximum value at the grid level with the distance from the grid and/or the ratio of values obtained in reinforced soil to the values obtained in non- reinforced soil. If several grids are tested in the same soil, and if the soil-grid interaction level is determined for each case, then the grid most appropriate for the material under study can be selected, and the proper vertical distance of grid layers in reinforced soil can be defined. Using this new testing technology, several grids were subjected to pullout testing, in original form and without ribs, in the direction orthogonal to the pullout. The interaction of grid and soil at various displacement rates was defined before and during pullout. Tests were performed with three different gradations of soil (sand to gravel) at moderate and low vertical stress levels. Test results show that the effect of ribs increases with the grain size of soil. The total pullout resistance, and the level of soil-grid interaction (via wave velocity), are compared for normal grid and grid with no ribs.

Izvorni jezik
Engleski

Znanstvena područja
Građevinarstvo

POVEZANOST RADA