Using Three-Dimensional Finite Elemnt Method To Assess Effects Of Tunnel Construction On Building

With the increasing development in urban areas, the assessment of effects of tunnel-induced ground movements on adjacent structures becomes an essential part in constructing underground railways. This thesis mainly aims to assess effects of tunnel construction on ground movements and further building deformation by using three-dimensional finite element method.In order to achieve this objective, appropriate finite element models in greenfield condition and in the condition with concrete framed building on ground surface respectively have been built by using ABAQUS/CAE for three-dimensional analysis with the finite element method theoretically based on Potts and Zdravkovic (1999) and Potts and Zdravkovic (2001). Firstly, to choose approapriate parameters and geometry dimensions based on engineering background of this thesis for three-dimensional finite element models; secondly, to consider various parameters including lining stiffness, structure stiffness of building and the ratio of building offset and width e/B, and then to compare with field measurements and related design curves. From the results obtained, it is concluded that when without building constructed, surface settlements along the transverse and longitudinal directions increase respectively with the development of excavation length, and the less lining stiffness is, the more surface settlements become; when building constructed with e=0but with different storeys, building displacements in both sagging and hogging areas become smaller with the increase of building stiffness; when building constructed with constant storey but with different e/B, the increase of e/B leads to smaller displacements of building in the sagging area but larger displacements of building in the hogging area.Innovations in this thesis are stated below:1."Relative stiffness method" was used to equivalently simulate the real building with the advantage of saving amount of time and calculation storage space by using three-dimensional shell units and entering various parameters to simulate building;2. In the parametric analysis, e/B which combines building offset and building width was considered;3. Two parameters, relative bending stiffness p*and modification factor M, were used to normalize all parameters and finally to compare with calculation results and design curves in order to assess the safety of surface building.There are totally65figures,15tables and71references used in this thesis.