Differential Settlement Characteristic Of Highway Widening Project

The number of the cars is constantly increasing,and with the rapid development of thenational economy, the original road construction can’t meet the increasing traffic demandsand needs to be broadened. Due to different consolidation extent and compression betweennew roads and old ones, the different characteristics, different settlement appears betweenthem, which leads to vertical cracks between new-old fringe zone and road surface. To solutethe important technical problem of highway widening project, this paper systematicallyresearched on the interaction between new and old embankments by methods of in-site test,numerical simulation and theoretical analysis.The main work and conclusions can be given asfollows::(1)Analysis on the deformation behavior and the influencing factors of the differentialsettlement of widened subgradeBased on geotechnical theories and FEM software, a numerical model is established forthe widened subgrade into which the original design parameters and the properties ofsubgrade materials are incorporated.(2) Full size model testBased on the large-size ground settlement simulator a new model test system that canbetter simulate the differential settlement of the subgrade or the foundation of a widened roadis developed for the research program. The new system incorporates a series of designconditions of the widened road such as the splicing between the new and the old subgrade, thecharacteristics of different pavement layers, and the application of pavement load. Fibergrating-based system is developed to monitor, measure, and evaluate various features of awidened road subjected to differential settlement, which includes the deformation both of thenew and the old subgrade; the variation of subgrade earth pressure; the deformation behaviorof geosynthetic, and the stress or strain variation of pavement layers.The research as presented by this paper regarding the behavior and control standard forthe differential settlement of widened subgrade is expected to provide reference for theresearch, construction, design, and specification in respect in the future and is believed to beof considerable economic and social benefit.