3D Numerical Analysis of the Effects of an Advancing Tunnel on an Existing Loaded Pile Group

M. A. Soomro, D. K. Bangwar, M. A. Soomro, M. A. Keerio

Abstract


Tunnels are often preferred for underground transportation in densely populated areas. In these areas, it is almost inevitable for tunnels to run close to some existing pile foundations. Since tunnelling activities induce stress relief and soil movement in the ground, existing piles may suffer from additional axial and lateral forces, bending moments, settlements and lateral deflections. Most of the previous researches on the responses of pile foundations due to tunnel construction were carried out under the plane strain condition. In this paper, a three-dimensional, elasto-plastic and coupled-consolidation finite element parametric study has been carried out to investigate the effects of a 6 m open-face advancing tunnel on a two by two pile group in saturated stiff clay. The influence of different cover-to-diameter (C/D) tunnel ratios (namely 2.0, 2.5 & 3.0) was studied. The objectives of this study are to determine the changes in axial load distribution, changes in shaft resistance along the shaft of pile group and settlement of pile cap due to an advancing open-face tunnel.


Keywords


finite element analysis; open face tunnelling; settlement of pile cap

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References


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