| Ground settlement induced by excavation is a key problem in tunneling. Recently, the most important theoretical methods for predicting the ground settlement induced by tunneling are empirical methods and analytical methods. But, most of them are applicable for tunnel with circular cross section and the ground loss is difficult to select. This paper uses equivalent area method to change general shaped cross section tunnel into circular one, as the ground loss is selected from fnished tunnel that was constructed by similar working operation in the same ground.Based on the project of Guomao Metro Station in Beijing, proper theoretical methods are selected to predict the ground settlement and affection to adjacent bridge foundation. Then the theoretical result is compared with the one done by numerical analysis. Through the comparison, we see that Loganathan analytical method is fit for predict ground settlement and affection to nearby pile foundation in Guomao metro construction.Tunnel excavation will have negative influence on nearby overpass. Although there have been some prescriptive values of pier settlement, the one for irregularly shaped slab is not carried out. The irregularly shaped slab member of Guomao Bridge, which is made from partial prestressed concrete, is within the influence range induced by tunneling and very dangerous. General finite elements analysis software of ANSYS is applied to set maximum allowable settlement for coping support of the bridge slab. Then, the maximum allowable settlement for coping support is changed into values of irregularly slab pier settlement.Lastly, settlement of pile foundations attaching to this slab member, induced by Guomao metro construction, is predicted by Loganathan analytical formulation. And the slab member's disease caused by settlement is estimated. |
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