Deformation Characteristics of the Pile-anchor Supporting Structure of Deep Foundation Pit with Cracks

Due to the characteristics of a large amount of excavation, long construction period and complex construction environment, deep foundation pit engineering is easy to induce construction safety accidents. The full excavation process of the foundation pit supported by multi-layer prestressed anchor cable pile plate retaining wall was simulated utilizing a three-dimensional numerical model established by FLAC3D, based on the deep foundation pit project with cracks in Chongqing. Soil and supporting structure's deformation characteristics in the excavation process were analyzed based on the numerical results. Numerical result and actual measurement indicate that: (1) the deformation of supporting structure system and the settlement distribution outside the pit have obvious spatial effect under the influence of cracks and adjacent foundation pit buildings; (2) the relationship between the bending moment of the crown beam at the corner of the foundation pit and the excavation depth is obviously different from that in the middle of the foundation pit; (3) the deformation of the supporting pile in the middle of north and south side of the foundation pit is compound type, while deformation of the supporting pile in the central part of the east and west side is cantilever type; (4) the results obtained by HS soil constitutive model are in good agreement with the measured results. The numerical results of surface subsidence at the monitoring point are close to the measured data, which confirms the reliability of the numerical model. The research results can provide practical reference for similar projects in the future.