基于多元荷载耦合作用下高速铁路交叉隧道动力响应及损伤机理研究

For the current research achievement of dynamic response and damage mechanism of cross tunnel is mainly focused on a single load. Based on coupling effects of multiple load, this project intends to through numerical simulation, model experiment, field test and theoretical analysis to determine the characteristics and change rules of the dynamic modulus and damping of surrounding rock and lining, and also to determine the energy dissipation law and the stiffness attenuation characteristics of cyclic shear test. At last, established a practical dynamic constitutive model of surrounding rock and lining. Under the action of coupling effects of multiple load, analysis the internal microscopic damage mechanism after macro fatigue failure of tunnel typical surrounding rock. According to the whole process stress---displacement curve, select the appropriate damage variable, establishing the damage evolution equation and constitutive equations. At last, put forward a dynamic shear damage constitutive model of fragment expression material. On this basis, building a coupling three-dimensional dynamic model of the interaction between surrounding rock and tunnel structure under the action of multiple load. Analysis of the transient dynamic response and fatigue characteristics of tunnel structure, to reveal the dynamic responses law of the lining structure because of surrounding rock and lining structure parameters. And study the propagation rules of tunnel lining crack under the action of coupling effects of multiple load and the evaluation of Crack effects on the safety of the tunnel lining. Research results can provide the theoretical foundation for cross tunnel dynamic problems under the action of Multiple loads.

针对目前交叉隧道动力学响应及损伤机理方面的研究成果主要集中于单个荷载作用情况，本项目拟通过数值模拟、模型试验、现场试验和理论分析等手段，确定基于多元荷载耦合作用下围岩及衬砌的动力模量、阻尼的特点和变化规律及循环剪切试验中的能量耗散规律和刚度的衰减特性，建立围岩与衬砌的实用动力本构模型；分析多元荷载耦合作用下隧道典型围岩发生宏观疲劳破坏的内部微观损伤机理，根据剪应力-位移全过程曲线，选择合适的损伤变量，建立损伤演化方程和本构方程，进而提出一个分段表述的材料动态剪切损伤本构模型；在此基础上，构建多元荷载作用下围岩与隧道结构相互作用的耦合三维动力学模型，分析隧道结构的瞬态及疲劳动力响应特性，揭示围岩及衬砌结构参数对衬砌结构动力响应的规律；并研究既有隧道衬砌结构在多元荷载耦合作用下衬砌裂缝的扩展规律及裂缝对隧道衬砌的安全性影响评价。研究成果可为多元荷载作用下的交叉隧道动力学问题奠定理论基础。

针对目前交叉隧道动力学响应及损伤机理方面的研究成果主要集中于单个荷载作用情况，本项目拟通过数值模拟、模型试验、现场试验和理论分析等手段，确定基于多元荷载耦合作用下围岩及衬砌的动力模量、阻尼的特点和变化规律及循环剪切试验中的能量耗散规律和刚度的衰减特性，建立围岩与衬砌的实用动力本构模型；分析多元荷载耦合作用下隧道典型围岩发生宏观疲劳破坏的内部微观损伤机理，根据剪应力—位移全过程曲线，选择合适的损伤变量，建立损伤演化方程和本构方程，进而提出一个分段表述的材料动态剪切损伤本构模型；在此基础上，构建多元荷载作用下围岩与隧道结构相互作用的耦合三维动力学模型，分析隧道结构的瞬态及疲劳动力响应特性，揭示围岩及衬砌结构参数对衬砌结构动力响应的规律；并研究既有隧道衬砌结构在多元荷载耦合作用下衬砌裂缝的扩展规律及裂缝对隧道衬砌的安全性影响评价。研究成果可为多元荷载作用下的交叉隧道动力学问题奠定理论基础。