The Research Of Tunneling-induced Ground Surface Movements And Their Influence To Adjacent Utilities

Tunneling will inevitably result in a loss of ground due to soil deformation and displacement into the opening. The tunneling-induced soil movement and deformation may do damage to the pre-existing structures and underground utilities. It is necessary to predict the ground surface movements and their influence to adjacent utilities so that precautious measures can be taken to protect these utilities from tunneling. A FEM computational model is established in according to the characteristics of tunneling, and elastic-plastic FEM is used to research into the influence of the tunneling on ground movement and underground utilities, and the main content of this paper as follows: 1. The displacement loading finite element method is used to simulate tunneling, and the analogue method and computation formula are also brought forward. Moreover, a reciprocal calculating program, DLFEA-TGM, is developed. The tunneling-induced ground movement and characteristic of stress variation are analyzed. 2. A reciprocal FEM analogue method is brought forward, by means of taking into account the interaction of tunneling, the peripheral soil and underground utilities. And the calculating program, DLFEA-TPR, is developed to calculate the tunneling-induced deformation and stress of adjacent utilities. 3. Simulation analysis of construction of Thunder Bay tunnel in Canada and a subway in Shenzhen is carried through, and the settlement of ground and adjacent underground utilities is computed. The calculating results are in accord with the field data. 4. Influencing factors of tunneling on adjacent underground utilities are analyzed, which mainly include the relative position of pipelines and tunnel, ground lose, buried depth of pipelines, tubes and so on. And the corresponding charts are obtained to provide a reference for security appreciation of underground utilities. 5. Security discrimination method and protective measures of underground utilities are generalized and a new security discrimination method of pipelines based on FEM is put forward.