大型地下空间结构地震风险评估方法

地下结构的薄弱环节在地震作用下可能发生破坏,进而影响整个结构体系的整体稳定性,地下结构的抗震能力成为结构工程领域研究的热点问题之一。采用弹塑性时程分析与风险矩阵相结合的方法对地下结构地震风险进行评估,以1995年阪神地震中遭受严重破坏的大开地铁车站为例阐明该方法的具体步骤。弹塑性时程分析能够考虑地下结构的各种复杂情况,直观地得到地下结构的损伤破坏情况,根据破坏情况建立风险矩阵对结构进行系统的风险管理。结果表明,弹塑性时程分析结合风险矩阵的风险评估方法具有较好的精确性和可靠性,适用于重要大型地下空间结构的地震风险评估。

Assessment of seismic risk of large underground structures

When st ro ng shock happens, the foundat ion soil may underg o larg e deformat io n and be fo llow ed by the failure o f w eak par ts of the structure. T o evaluate the seismic r isk of underg round st ructure, a risk assessment method w as proposed combining elasto-plast ic t ime histor y analysis w ith risk matr ix . The implementat ion procedur e, the basic funct ions and the special features of the method w er e int ro duced in detail. The elasto-plastic time history analy sis could describe the failure modes of the underg round st ructures by considering dif ferent complex condit ions. According to the damage o f the st ructure, the seismic risk mat rix w as established and the seriousness of seismic risk w as obtained. T aking Dakai subw ay station as an example, the dynamic responses under three earthquakes of dif ferent grades w ere simulated by elastoplast ic t ime histo ry analy sis, and the risk assessment o f the st ructur e w as analyzed by the risk matr ix metho d. The result show s that the metho d combining elasto-plast ic t ime histor y analysis w ith risk matr ix is useful and suitable for seismic risk assessment of larg e under ground st ructures