Investigation Of Influence Of Ground Surface Settlement Induced By Tunnel Excavation On Adjacent Buildings

With the development of subway tunnel, environment damage due to the construction of tunnel attracts more and more attention. During and after the construction the tunnel should be responsible for the damage which can occur at the appearance of buildings or cause functional expense for the buildings. The cost of economy for strengthening buildings is relatively significant. In general, the protecting of buildings is not included in the design when starting a subway project, and it depends mainly on the control of ground surface settlement under construction. Now it can often be done to set a limited settlement for protecting buildings, for example, like 3cm for Beijing. If the limit was exceeded the adjusting of the order of excavation or the correction of initial plan could be done. This processing, however, ignores specific type of buildings and corresponding response to the tunnel excavation for the buildings, then those strengthening measures are not very essential, sometimes it seem to be very conservative. To clearly understand the tunnel induced damage and the interaction of structure and tunnel, this paper collects damage evaluation details and makes a numerical modeling of the interaction, finding some useful laws and providing guidance for the construction close to building. Emphases of this paper are placed on dynamic construction process, sensitive analysis of parameters, calculation of deformation parameters reflecting the structure'damage, comparison of coupled analysis with traditional approach for the evaluation of structure damage, and the generalization of evaluation approaches. Several main conclusions are listed as follows: (1) With the proceeding of tunnel excavation, differential and mean settlement increase and are close to stable value; (2) The presence of structure confine the deformation of ground surface, evening the concave and convex area caused by tunnel construction, and due to the viscous and frictional effect of interface between the foundation and soils, horizontal displacement and strained are significantly confined; (3) The structure also confines displacement occurring around the tunnel, which include lateral and vertical displacement; (4) When tunnel approaching the structure, internal forces of tunnel liners are increased to different degree; (5) The distance between buildings and tunnel, burial depth difference and the...