地下结构“可修”状态的层间位移角限值研究

Research on Limiting Value of Interlayer Displacement Angle of Underground Structure in"Repairable"State

我国地下结构抗震一般采用两阶段设计,抗震设防目标一般为“中震不坏、大震可修”,高于地上结构。规范中“大震可修”的性能指标以层间位移角表示,但层间位移角限值的确定依据并不明确。以地下结构“可修”状态的这一抗震性能指标为研究对象,首先对比国内外常用抗震设计规范中“可修”状态的层间位移角限值,分析不同规范性能指标存在差异的原因;然后,通过统计国内外框架结构和剪力墙结构拟静力试验的结果,评估我国抗震规范“可修”状态层间位移角限值的合理性;最后,以地铁车站和地上框架结构为例,通过推覆分析对比研究地下与地上结构的损伤破坏规律,比较地下结构"可修"层间位移角限值与地上结构的差异。研究结果可为地下结构抗震设计规范的修订提供参考。

In China, two-stage seismic design is generally adopted for the underground structures. The target of seismic fortification is generally "not damage in moderate earthquake, repairable in major earthquake", which is higher than ground structures. The performance index of "repairable in major earthquake" in the specification is expressed as the interlayer displacement angle, but the basis for determining the limiting value of interlayer displacement angle is not clear. Taking this seismic performance index of the underground structure in the "repairable" state as the research object, firstly, the limiting values of interlayer displacement angle in the "repairable" state in the common seismic design specifications at home and abroad are compared, and the reasons for the difference between the performance indexes of the different specifications are analyzed. Then, according to the statistic results of pseudo static tests of frame structures and shear wall structures at home and abroad, the rationality of the limiting value of interlayer displacement angle in "repairable" state in the seismic specification of China is evaluated. Finally, taking a metro station and a ground frame structure as the examples, the laws of damage and failure of the underground and ground structures are compared and studied by pushover analysis. The difference of the limiting values of interlayer displacement angle in the "repairable" state between the underground structure and the ground structure is compared. The research results can be referred for the revision of underground seismic design specification.