考虑结构—土—结构动力相互作用的重力坝地震响应分析

Structure-soil-structure dynamic interaction-considered seismic response analysis of gravity dam

为研究地震作用下相邻新、老重力坝的彼此相互作用对响应的影响规律,基于阻尼溶剂抽取法(Damping Solvent Extraction Method,简称DSEM)模拟无限地基辐射阻尼效应的思想,建立了新坝—土—老坝动力相互作用模型,并推导了具体的数值实现公式。进而运用UPFs的二次开发特点,通过创建用户单元在ANSYS中实现了所开发模型的嵌入。最后,结合工程实际条件,探讨了地震作用下老坝拆除前后对新建重力坝动力响应的影响规律。计算结果表明:老坝的存在降低了新坝在地震动作用下的动水压力的大小,在老坝拆除前后对新坝的动力特性分布规律影响较小,而对于幅值有一定的影响。本模型表现出了良好的工程适用性,结合通用有限元软件丰富的结构单元模型及非线性分析能力可开展类似工程的抗震安全评价分析。

In order to study the influence law of the response under the earthquake action of the dynamic interaction between the new and old adjacent gravity dams,the idea of unbounded foundation radiation damping effect is simulated based on the damping solvent extraction method(DSEM)and a new dam-soil-old dam dynamic interaction model is established,and then the formula for the numerical implementation is deduced.Moreover,the embedding of the developed model into ANSYS is realized through establishing user element by applying the characteristics of the secondary development of UPFs.Finally,the influencing laws of the dynamic responses from the old dam before and after its removal on newly built dam are discussed in accordance with the relevant actual engineering condition.The calculation result shows that the existence of old dam lowers the hydrodynamic pressure of new dam under earthquake action and has slight influence on the distribution law of the dynamic characteristics of new dam before and after removal of old dam,but has a certain influence on its amplitude.The model exhibits a better engineering applicability,with which the seismic safety assessment on the similar project can be made in combination with the general finite element software with rich structural unit models and the non-linear analysis capacity concerned.