基于《城市轨道交通结构抗震设计规范》的地铁地下结构抗震设计问题探讨

Discussion on Seismic Design of Underground Subway Structure Under the Code for Seismic Design of Urban Rail Transit Structure

GB 50009—2014《城市轨道交通结构抗震设计规范》的颁布为我国城市轨道交通结构的抗震设计提供了技术标准。如何理解和运用该规范是做好地下结构抗震设计的基础。针对该规范,通过与地上民用建筑抗震设计相关参数的对比分析,重点对地铁地下结构的抗震设防目标及水准、地震动参数及抗震措施等方面进行了探讨。结果表明:对于一般的地铁地下结构可遵循"两水准、两阶段"的设计思路;结构抗震设计地震动参数的选取应与其设计基准期一致;结构抗震等级应通过结构形式、结构高度、地震烈度等综合考虑确定,并根据不同抗震等级来进行结构抗震措施的调整;应明确地震作用效应调整方法,尤其针对地下区间矿山法马蹄形和盾构圆形隧道,应给出更为具体的抗震构造措施,以完善地铁地下结构抗震措施的可操作性。

The promulgation of the Code for Seismic Design of Urban Rail Transit Structure provides a technical standard for seismic design of rail transit structure in China,good understanding and implementation of the new code is the foundation for the seismic design of underground structure.Through a comparison with the related parameters in civil building construction,the goal and level of seismic fortification,the ground motion parameters and the seismic measures are mainly analyzed.The results show that the seismic design for ordinary subway underground structure can follow the"Two-level,Two-phase"design principle;while the ground motion parameters in seismic design should be selected according to the structural design reference period;seismic grades should be comprehensively determined by structural form,structural height and seismic fortification intensity,on this basis the seismic measures should be adjusted;the effects of adjustment method should be clarified especially for the horseshoe-shaped and circular tunnels built with mine tunneling method;and more detailed measures for seismic structures should be adopted to improve the maneuverability of underground structure seismic measures.