混凝土重力坝动力弹塑性损伤安全评价

Safety assessment of concrete gravity dams based on dynamic elastoplastic-damage analysis

本文利用能考虑混凝土软化并可反映实际损伤耗散的模型,对结构进行动力损伤分析,用损伤量这一表明材料或结构渐进破坏的指标,并结合结构应力重分布,对大坝进行地震安全评价。对Koyna坝动力弹塑性损伤分析结果表明,大坝的最大拉应力、最大压应力和损伤分布与Koyna大坝实际破坏情况大致相符,验证了计算模型的有效性。将其应用于三峡大坝的一个非溢流断面,得到地震作用下的弹塑性损伤响应,并据此评价大坝结构的安全性能和超载潜能。研究表明,利用损伤力学进行混凝土重力坝安全评价将取得较合理的结果,损伤是除应力之外对结构安全评判的可信指标。

A damage mechanics model associated with strain softness after post-peak for concrete is proposed, which can reflect reasonable damage dissipation of concrete fracture. Combined with redistribution of stress, the damage index is used to perform safety assessment of gravity dams in dynamic elastoplastic-damage analysis. The validity of the model is verified by the observation data of the Koyna Dam. The model is applied to analyze a section of the gravity dam in the Three Gorges Project. The elastoplastic-damage response of the dam is obtained and the safety and overload potential of the dam are assessed accordingly. It is concluded that damage is a credible nonlinear index which can be used to assess the safety of dams subjected to earthquake.