Influences of Urban Viaduct Pier Caps on Uneven Settlement of Roadbed

Abstract

Uneven settlement widely occurs on the roadbed under urban viaducts in operation. Previous studies focused on the effect of soft soil foundation on the uneven settlement of roadbed, without considering the phenomenon and mechanism of uneven settlement at the junction of pier cap and the roadbed under viaduct. The interaction is now considered between the buried depth of cap, the relative stiffness between cap and road subgrade, and the uneven settlement of roadbed. Using the Midas GTS NX software, a numerical analysis model of the deformation of roadbed under viaduct is constructed to study the influence of viaduct cap foundation on the uneven settlement of roadbed under viaduct. The simulated results of uneven settlement of roadbed caused by urban viaduct pier cap show that (1) when the buried depth of cap exceeds 2.35 m, with the increase of buried depth, the fall of roadbed settlement tends to decrease, but the decreased amount is not significant. Considering the factors such as construction cost and complications of construction technology, it is suggested that the best buried depth of cap is about 2.5 m. (2) The fall of roadbed settlement decreases with the decrease of relative stiffness between cap and roadbed. When the relative stiffness exceeds 6.3, the decreasing trend of settlement fall is not significant. The concrete roadbed should have more stiffness in order to reduce the settlement.