震裂岩体隧道灾变失稳机理及安全控制对策

Taking the mountain tunnels passing through a large quantity of shattering rock mass which neither move nor collapse in infrastructure construction in earthquake areas as research objects, adopts some advanced research methods like data collection，in-situ investigation and tests, numerical simulation and lab vibration test to study on the variation characteristics of typical characters of rock mass before and after earthquake, and the mechanical mechanism of fracture for rock mass under dynamic effect of earthquake, and then revealed basic damage properties and formation-evolution mechanism of shattering rock mass. Under this premise to further research on the rules of mechanical evolution and typical disaster form of shattering rock mass about tunnel surrounding rock-structure stability from deformation to unstable failure, characteristics of seismic disaster for tunnel engineering and dynamic response rules of surrounding rock-structure system under aftershock, bearing mechanism and aseismic-cushioning effects of reasonable support structure system for tunnels in shattering rock mass. And then revealed the failure mechanism and disaster character of shattering rock mass tunnel during construction. Finally, put forward security control methods and countermeasure of tunnels passing through shattering rock mass in strong earthquake areas.

以震区基础设施建设过程中穿越大量"松"而未"动"，"裂"而未"塌"的山区隧道为研究对象，基于广泛的资料搜集、现场调研和测试，结合室内振动试验与数值模拟分析等多种研究手段，通过对地震前后岩体典型性状的变化特征、地震动力作用下岩体变形破裂的力学作用机理的深入研究，揭示震裂岩体基本特性及成因机制，以此为基础，进一步开展震裂岩体隧道围岩-结构稳定性变形到失稳破坏的力学演变规律与典型灾害型式、余震作用下隧道工程震害特征、围岩-结构体系动力响应规律及震裂岩体区隧道合理支护结构体系的承载机理及抗减震效应的系统研究，进而揭示震裂岩体隧道修建过程中失稳机理与灾变特性，提出穿越震裂岩体区隧道的安全控制方法与对策。

项目以穿越强震动力作用后形成的大量“松”而未“动”，“裂”而未“塌”的软岩隧道为研究对象，以5.12汶川地震发震断裂---龙门山活动断裂带上在建的广甘高速公路隧道群为依托，基于广泛的资料搜集与现场调研，结合现场试验、室内模型试验、数值分析等综合研究手段，通过对强震后震裂岩体隧道关键科学问题的系统研究，揭示了强震区震裂岩体的基本特征及成因机制；探明了震裂岩体区软岩隧道失稳破坏模式、影响因素及其成因机制。建立了强震区震裂软岩隧道安全控制基准及管理控制体系，探明了震裂软岩隧道各工法下围岩-支护结构的力学行为特征及相互作用机理，确定了震裂岩体隧道的适宜工法及相关参数指标，揭示了震裂软岩隧道的支护承载特性及演变机理；剖析了震裂软岩隧道支护结构变形及受力的长期演变特性，确定了支护结构体系中关键性设计参数。探明了余震作用下围岩-支护结构的动力响应规律，揭示了震裂岩体区软岩隧道施工期余震作用下的失稳机理。提出了震裂岩体隧道防失稳控制对策。形成的系列研究成果对跨龙门山断裂带及其影响区内的在建及拟建的大量铁路、公路软岩隧道建设提供了宝贵的技术参考，揭示的强震区余震作用下震裂岩体隧道的动力响应特性及失稳机理对我国隧道地震研究进行了有益补充，研究成果对我国高烈度西部山区的隧道建设具有极高的理论参考价值与现实指导意义。