The Research of Pile Responses Due to Tunnelling
|School||Hefei University of Technology|
|Course||Bridge and Tunnel Engineering|
|Keywords||tunnel excavation pile foundation soil movement pile behaviour|
In recent years, many big cities have constructed subways to meet therequirement of people’s transportation. In the urban areas, tunnelling adjacent to anexisting pile will affect the pile foundation inevitably. This paper used a finitedifference method project, FLAC3D, to predict the effects on pile foundation due totunnelling. Soil behaviour was assumed to be an elastic-plastic model based onMohr-Coulomb criterion. Liner and pile was assumed to be elastic. Tunnellingexcavation procedure was modelled by a three-dimensional model.In this paper, tunnelling-induced ground movements were analysed by theproject FLAC3D. Ground movements caused by tunnelling were very important tothis paper, for tunnelling-induce ground movements made a connection betweentunnelling and pile responses. To study tunnel-induced ground movements couldhelp us understand a pile’s behaviour caused by tunnelling well. The ground lossand ovalization of the tunnel were considered in this paper. Comparing withempirical methods, numerical methods could give a good agreement.Numerical analyses changed length and position of the pile to study thefeatures of pile behaviour caused by tunnelling. The main results indicatethat:(1)For short piles, which length is10m and15m, incline is the major form,while long piles with the length of20m and25m bend.(2)The pile length influencethe behaviour of a pile observably, especially when the pile tip is below thehorizontal axis of the tunnel.(3)Maximum bending moment and maximum axialforce decrease with increasing value of distance between pile and tunnel centerline.When a pile is located far away from tunnel centerline, which distance is15m inthis study, tunnelling induced bending moment and axial force become neglectable.The conclusions in this paper may be useful to protect the environment effectsinfluenced by adjacent tunnelling.