Influence on the neighboring viaduct pier’s extending footings was numerically studied by using MSC.Marc 3-D software

which induced by the tunnel staged construction and the traffic loading during the working period. The incremental developments of these extending footings’ stresses

settlements and inclinations were analysised

as well as the retaining structure’s lateral displacements. And the obtained results indicate that: (1) These extending footing’s unloading during the construction is due to that the tunnel bottom level is higher than these extending footing’s. (2) The No. 6 extending footing’s inclination and settlement is mainly induced by the planning traffic loading which directly acting on its one top side. (3) The extending footing’s maximum inclination is 0.000 6. (4) The extending footing’s maximum settlement induced by the tunnel traffic loading is 3.7 mm. Combined with the obtained results of the groundwater seepage

it deems that the tunnel construction and working period does not endanger the viaduct’s safety theoretically.