| With the rapid development of construction of urban rail traffic in the soft soil area,subway shield tunnels in urban areas often need to pass through existing structures.It's one of hotspots of soft soil tunnel theory to study disturbance mechanism of piles foundation induced by shield excavation.Taking the Lishexincun-Yinzhoudadao section of No.2 line of Ningbo subway as an engineering background,the behavior of adjacent pile foundation caused by shield construction is studied by using comprehensive analysis of the method,including numerical simulation and field monitoring,in this paper.First of all,applying the basic principle of the environmental effect caused by shield construction,combining with engineering practice of the Lishexincun-Yinzhoudadao section of No.2 line of Ningbo subway,the paper collects and analyzes monitoring data of surface subsidence,deformation and displacement of building with pile foundation under shield construction,in order to put insight into law and characteristic of surface subsidence,deformation and displacement of building with pile foundation.Secondly,a three-dimensional elastic-plastic finite element model of tunnel-soil-pile-frame structure is established by Abaqus.The comparison between simulation data of displacement and deformation of frame structure with pile foundation induced by shield tunnel excavating and field test data verify the rationality of numerical simulation.Finally,a three-dimensional elastic-plastic finite element model of tunnel-soil-pile is established by Abaqus,aiming at simulating disturbance of forced layer at the end of the pile and the growth of pile-side friction resistance.The paper put insight into the nature of interaction of pile-tunnel and the displacement,deformation and mechanics disturbance mechanism of pile foundation during shield tunnel constructing,based on the theory of settling tank,the theory of soil disturbance partition and the non-linear contact theory of soil-pile interaction. |
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