Simulation of Soil Deformation Due to Pit Excavation with Particle Flow Code

Abstract:

Numerical simulations of macromeso mechanical behaviour of an excavation process supported by deep mixing piles were performed by secondary exploitation using the Particle Flow Code in 2 Dimensions(PFC2D code),which was developed based on the assemblies of particlular materials.The PFC2D model of a real pit was established according to similarity theory,and the mesoscale parameters of soils in the model were determined through a series of calibration biaxial tests in order to link the change of mesoscale fabric to macroscale response.Deformations of ground surface were analysized for all excavation steps,including heaves of pit bottom and horizontal displacements of mixing piles.The study verifies that PFC2D can be used to visualize the evolution of excavation process.Comparison between simulation results and the measured data proves the feasibility to explore the interaction mechanism of retaining structure and soils around from the prospect of the mesomechanics.

Key words:excavation of foundation pit; mixing piles; particle flow code; deformation of ground surface; bottom heaves