Document Type : Article
Department of civil engineering, Shiraz Branch, Islmic Azad University, Shiraz, Iran
Master of science of geotechnical engineering, Estahban Branch, Islamic Azad University, Iran
Master of science of highway engineering, Shiraz Branch, Islmic Azad University, Shiraz, Iran
An investigation into the causes of settlement and its control can place an obstacle to such hazards as derailing of a train due to the railway settlement. In this study, the effect of both geogrid and the geogrid anchor concerning the railway ballast layer settlement reduction has been taken into account. For this purpose, the ballast performance in the field conditions was simulated using a small-scale box test. In this experiment the static load was considered as the sum of the train and passenger weightand the dynamic load relating to the train vibration. Since this research aims at launching an investigation into the influence of utilizing geogrids in order to reduce the ballast settlement, this experiment has been carried out by considering the geogrid and geogrid anchor layer, the loading frequency variation, the amount of loading, the geogrid position, the number of geogrid layers and the related distances. Also, the results obtained from the empirical model have been analyzed and compared. A number of relations based upon the test results have been developed to estimate the permanent settlement relative to the dynamic load and the number of reinforcement layers.