The Study Of Ground Movements And Adjacent Pile Responses Induced By Tunnelling

Underground transportation systems have increased rapidly in many large cities these years in the world,especially those facing a problem with traffic. This system requires a tunnel construction which generates ground displacements and deformations which can affect the preexisting buildings and main services in urban sites and could lead to unacceptable damages. In an urban environment,many high-rise buildings are supported by pile foundations and tunneling almost invariably will cause ground movements,which in turn will impose axial and lateral forces on the pile foundations. So it is important to research the effects of tunneling on soil around and adjacent pile foundations.In this thesis,the author first takes a review on the computational theories of the ground movements and pile responses induced by tunnelling. Second,a brief introduction is made about theories of constitutive models and ground movements. Then a few words are said about the Finite Element Analysis Software-ABAQUS,which is used to analyze the ground movements and pile responses in a two-dimension FEA model. The contact interactions between soil and lining,and between soil and pile are taken into account. The constitutive model employed is Mohr-Coulomb plasticity with linear elasticity assumed within the yield strength surface.The main study of this thesis includes two parts. First,estimation of the free-field ground movements induced by tunneling (both vertical and horizontal),i.e.,the effects of tunneling on soil around without the presence of the pile,and comparing the results with the elastic analytical results;second,the imposition of these movements on the adjacent pile and the computation of the consequent pile responses.