Study on the Influence of Fault Dislocation on Metro Viaduct and its Structural Optimization
The creep-slip and dislocation of urban active faults poses a potential safety threat to municipal construction.Different from abrupt earthquake disasters,the creep-slip dislocation of fault is a slow-deforming disaster with controllability.In order to reveal the influence of creep-slip dislocation on metro viaducts,this paper takes the Xi'an Metro Line 10 viaduct crossing the Weihe fault(F1)and Jingyang-Weinan Fault(F3)as the engineering background,a strata-fault zone-viaduct calculation model is established with finite numerical software,and the deformation characteristics of the metro box girder viaduct with different spans and pile lengths under the creep-slip dislocation of the fault are analyzed.The results show that the strata deformation in the viaduct site is approximately"V"shaped under the fault dislocation,and the influence range in the hanging wall is greater than that in the footwall of active fault.Under the creep-slip dislocation of active fault,the deformation of the bridge structure crossing active fault and the ground surface decreases with the increase of viaduct pile length,and when the span of the bridge is 40 m and the pile length is 60 m,the surface settlement and the deformation of box girder and pier of viaduct are the smallest.The deformation of the bridge structure is related to its angle across the fault zone.When crossing the fault zone at a small angle,the deformation of the bridge structure is greater than that of the orthogonal and large angle crossing conditions.When the viaduct crosses the fault zone at large angle obliquely or orthogonally,the optimal span of viaduct is about 40 m and the optimal pile length for bridge piles adjacent to the fault zone is about 55 m.When the viaduct crosses the fault zone at a smaller angle,the optimal span of viaduct is about 50 m and the optimal pile length of the bridge pile adjacent to the fault zone is about 60 m.The impact of fault dislocation of metro viaduct on the bridge can be reduced by adopting large angle intersection,appropriate pile length and bridge span length.
metroviaductfault dislocationnumerical simulationdeformation characteristicsoptimal span and pile length
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