Treatment Mechanism Research on the Roadbed Widening with Geosynthetics

In order to reduce the differential settlement and improve the stability of the subgrade when widening the old roadbed，the geosynthetics have been successfully adopted in the joint between the old and new subgrades. Based on the features of the geosynthetics-reinforced old road widening, the old and new subgrades and the pavement were regarded as a whole structure, and the numerical model was established on the basis of the assumption. By FLAC, the mechanism of geosynthetics-reinforced old road widening was discussed, the different effects under the different layer numbers of geosynthetics and roadbed filling height were studied, mainly from the aspects of displacement and surface stress of subgrade. The results show that geosynthetics not only effectively reduce the differential settlements and horizontal displacements of subgrade top, but also lessen and homogenize the average stress reflected from subgrade to pavement.