复杂层状岩基上重力坝极限抗震能力评估方法初探

针对复杂层状岩基上典型工程的特点,从结构系统功能的潜在失效模式出发,利用数值仿真分析方法,结合基于功能的地震破坏等级评价模型、基于断裂力学的坝体开裂行为分析模型和基于变形体突变的系统极限承载力分析评价模型,建议从坝体混凝土损伤破坏等级、开裂破坏模式、坝基岩体极限承载能力和系统稳定性突变等方面综合评价大型重力坝的极限抗震能力.实例分析结果表明,阿海重力坝溢流坝段极限抗震能力为0.550g～0.600g.基于数值试验的极限抗震能力综合评估方法,可以全面考虑各种关键性能对极限抗震能力的影响,避免了单一收敛性或系统突变评价准则的缺陷,在一定程度上弥补了振动台模型试验的不足.

Evaluation Method of Maximum Aseismic Capability of Gravity Dam on Complex Layered Rock Foundation

The performance failure of the gravity dam under ultimate seismic load is on important characteristic which means its aseismic capability has reached the limit, but there is no unified standard reference to make the evaluation. Based on the characteristics of typical engineering and the potential failure modes, with performance-based seismic damage assessment model, cracking behavior analysis model as well as the foundation stabilization safety and limit load carrying capacity analysis model, the maximum aseismic capability was studied and evaluated by focusing the emphasis on damage levels, cracking extending mode, foundation load carrying capacity and displacement jump of typical position for the gravity dams on complex layered rock foundation. Example results show that the maximum aseismic capability of the overfall section of Ahai gravity dam is evaluated as 0.550g-0.600g. The proposed method has been successfully applied to the maximum aseismic capability evaluation by considering the comprehensive influ- ence of the key performance failure. It avoids the shortage of the single convergence or abrupt system changeover criteria, and also overcomes the shortage of the experimental research to some extent.