Abstract

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Title:: Study on Mechanism of Reinforcing Soft Soil Foundation of Highway by Dumping Riprap to Extrude Silt

Author(s):: ZHU Yan-peng; CHEN Yan-jiao; School of Civil Engineering, Lanzhou University of Technology

Keywords:: foundation treatment; dumping riprap to extrude silt; reinforcement mechanism; numerical simulation; monitoring data

Abstract:: Selecting the 9th section of Lanyong firstclass highway which treating soft soil foundation by dumping riprap to extrude silt as the model, finite element software PLAXIS was used to make numerical simulation research and the numerical simulation results were compared with the actual monitoring data. Firstly, the subsidence, horizontal displacement and pore water pressure of foundation treated by dumping riprap to extrude silt and untreated foundation were compared. Secondly, a factor of the model was selected as variable, and the influences of the variable on the soft foundation treating effect by dumping riprap to extrude silt were studied. Finally, the simulation results were compared with the actual monitoring data. The results show that the foundation settlement and horizontal displacement significantly decrease after treatment. The composite modulus is larger and the integrity is stronger after treatment. The decrease of pore water pressure shows that the dumping riprap to extrude silt process accelerates the consolidation of foundation. The subgrade settlement decreases with the increase of width, modulus and thickness of riprap. Since the thickness of backfill sand changes irregularly, the riprap can be chosen according to the actual situation and local experience. The results of simulation and actual monitoring are not quite different, which meet the engineering requirements.