A series of large-scale cyclic tests was conducted using process simulation test (PST) apparatus to capture the influence of loading frequency (f) on the deformation and degradation behavior of ballast with and without geogrids. Fresh granite ballast and subballast having mean particle diameter (D50) of 42 mm and 3.5 mm, respectively and five geogrids of different aperture shapes and sizes were used in this study. The tests were conducted at f ranging from 10 to 40 Hz and up to 250,000 load cycles. The test results from the laboratory investigations confirmed that the deformation and degradation behavior of ballast is highly influenced by loading frequency (f). Moreover, the results showed that geogrid reinforcement stabilizes ballast by reducing the extent of lateral spreading (ld) and vertical settlement (Sv) and by minimizing particle breakage (BBI). The inclusion of geogrids also reduces the extent of vertical settlement in subballast layer (Svsb). In addition, the extent of volumetric (εv) and shear strains (εs) including void ratio (ef) and density (γbf) were found to be highly influenced by f. It is further seen that lateral spread and vertical settlement reduction index (LSRI and VSRI) of all the geogrids decreases with the increase in f. Moreover, it is revealed that with the decrease in LSRI, the extent of Sv and BBI increases. A correlation is developed between the deformations (ld and Sv) and interface efficiency factor (α). The effectiveness of geogrid in keeping the ballast in place is evaluated in terms of a new parameter ‘geogrid efficiency factor (Gef)’. The value of Gef for geogrids used is found to vary from 0.02 to 0.27. It is further shown that Gef under cyclic loading conditions is a function of the interface efficiency factor (α) evaluated under direct shear conditions.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Investigation of deformation and degradation response of geogrid-reinforced ballast based on model track tests


    Contributors:


    Publication date :

    2021-04-01


    Size :

    13 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




    Performance of Geogrid Reinforced Ballast under Dynamic Loading

    R. Parsons / M. Jowkar / J. Han | NTIS | 2012


    Characteristics of Geogrid-Reinforced Rubber-Coated Ballast under Cyclic Loading Conditions

    Alam, Md Naquib / Hussaini, Syed Khaja Karimullah | Transportation Research Record | 2024


    Deformation–Resistance Model for Geogrid-Reinforced Unpaved Road

    Leng, Jianjun / Gabr, Mohammed A. | Transportation Research Record | 2006


    Effect of Geogrid Reinforcement in Model Track Tests on Pavements

    Moghaddas-Nejad, Fereidoon | Online Contents | 1996


    Deformation-Resistance Model for Geogrid-Reinforced Unpaved Road

    Leng, Jianjun / Gabr, Mohammed | Transportation Research Record | 2006