Long-Term Settlement Behavior of a Highway in Land Subsidence Area

Abstract

Constructed transport facilities in soft deposits deform significantly due to long-term land subsidence. A great deal of research has been carried out to study the land subsidence–induced deformations of metro tunnels, with a few focusing on the performance of highways in soft deposits. Based on extensive field data of the Shanghai Middle Ring Highway (SMRH), this paper investigates the long-term settlement behavior of the SMRH, which consists of ground road and elevated road. Annual longitudinal settlement profiles of the SMRH are presented to study the responses of the ground road and elevated road to land subsidence. The accumulated longitudinal settlements are compared to the ground surface settlements in association with geological conditions. Moreover, a comparison of the deformation processes between the elevated road and subsoils is presented. Field data indicate that the whole highway, including ground roads and elevated roads, settled in the earlier stage, but part of the elevated roads heaved since 29. In the ground road part, ground road settled with the ground surface. However, in the elevated road part, the ground surface settled more significantly than the elevated road, with differential settlements ranging from 15 to 4 mm. The settlements of the elevated roads were invariably close to the total compression of soils below the pile tips and the elevated road heaved due to rebound of these soils.