非一致地震动作用下长大隧洞动力响应的时空效应与破坏机制研究

As an important infrastructure for national strategy and lifeline engineering, the long and large tunnels in west China are in the complex seismic geological environment and they have significant seismic safety problems, and the dynamic response and failure mechanism under non-uniform seismic excitation is urgent research topic. In this project, taking the Xianglushan tunnel of centralYunnan diversion as an engineering background, on the basis of the investigation and experience of earthquake damage of tunnels, using the geological survey, field testing, laboratory experiments, model test and numerical simulation methods, the spatial non-uniformity and input mechanisms of ground motion in the long and large tunnel site are investigated, and the dynamic model and analysis method are also developed; then, through studying three aspects, including the spectrum correlation between seismic excitation and dynamic response of surrounding rock, the spatial non-uniformity of seismic dynamic response in different surrounding rock, and the relevance and coordination of seismic dynamic response between surrounding rock and structure, the time-space effect of dynamic response of the long and large tunnel is revealed; last, dynamic damage evolution of surrounding rock in the unfavorable geologic structure belt is studied, dynamic interaction mechanism between the surrounding rock and structure and induced structural damage characteristics is analyzed, and dynamic failure mechanism of the long and large tunnel is revealed. The research results can provide theoretical and technical support for the seismic safety of the long and large tunnel, and also effectively push the development of the rock dynamics and underground engineering.

西部地区长大隧洞作为国家战略和生命线工程的重要基础设施，面临复杂地震地质环境，其地震安全问题突出,非一致地震动作用下的动力响应与破坏机制是亟待突破的理论与技术难题。本项目拟以滇中引水工程中的长大隧洞—香炉山隧洞为依托，以隧洞震害调查与经验认识为基础，通过地质调查、现场测试、室内实验、模型试验、数值模拟等方面的集成研究，探讨长大隧洞工程场地空间非一致性地震动的输入机制，发展长大隧洞地震动力响应分析模型与方法；通过研究输入地震动与围岩动力响应的频谱相关性、不同部位围岩地震动力响应的空间非一致性、围岩与结构地震动力响应的相关性与协调性，揭示长大隧洞地震动力响应的时空效应；通过研究不利地质结构带围岩地震动力破坏演化规律，分析围岩与结构动力相互作用机制及诱发的结构破坏特征，揭示长大隧洞地震动力破坏机制，从而为长大隧洞抗震安全提供理论与技术支持，在推动岩石动力学和地下工程学科发展方面发挥积极作用。

本项目以滇中引水香炉山隧洞为依托工程，采用理论分析、实验研究、数值模拟多手段综合开展了系统的研究，研发了隧洞围岩-衬砌接触面的循环剪切试验设备，提出了考虑法向闭合量与加卸载滞回效应的动力接触本构模型；构建了适用于地震作用下岩石材料的动态非线性本构模型，研发了一套面向对象的岩石地下工程地震动力响应的高效并行计算的有限元软件；基于随机过程理论，建立了适合长大隧洞工程场地的空间非一致性地震动模型，在此基础上，提出了考虑非一致性地震动的多点多维输入方法、输入与响应地震动相关性的分析方法，形成了非一致地震动作用下长大隧洞动力响应的模拟与分析方法。基于非一致性地震动输入方法，分析了输入地震动与围岩动力响应的频谱相关性、不同部位围岩地震动力响应的空间非一致性、围岩与结构地震动力响应的相关性与协调性，总结了非一致地震动作用下长大隧洞动力响应的时空效应。通过收集和整理隧道等地下工程灾害资料，建立了地下工程震害资料数据库，基于统计分析提出了地震作用下地下工程动力破坏模式；基于数值方法，分析了不同倾角、厚度和岩性不利地质结构带下围岩地震动力破坏演化规律，通过研究不同情况下不利地质结构带隧洞衬砌结构的震害变形及受力分布，揭示了非一致地震动作用下长大隧洞动力破坏机制。该成果可为长大隧洞抗震安全提供理论与技术支持。