重载铁路隧道基底结构损伤-脱空激励下衬砌劣化及服役性能研究

Dynamic response of tunnel base structural system , disengaging evolution mechanism of tunnel basement rock, cumulative damage of tunnel base structure and its service performance caused by cumulative damage/disengaging interaction under repeated dynamic loading of heavy haul train are the key issues to be addressed during heavy haul railway tunnel design, operation and maintenance..By analyzing the interaction between tunnel base structure/surrounding rock for heavy haul railway tunnel system, a three-dimension dynamic model of dynamic load/tunnel/ surrounding rock is established to study dynamic response characteristics for different disengaging conditions, optimal tunnel base conditions for different surrounding rock are thus concluded. Cyclic plasticity constitutive model of surrounding rock is introduced to set up dynamic calculation method under repeated dynamic loading, reveal evolution process and formation mechanism of disengaging. Based on the degradation behavior of concrete under dynamic load, the constitutive model with viscous cyclic plastic damage is established and the process of nonlinear cumulative fatigue damage of tunnel base structure is reconstructed. By means of high precision, large proportion (1:10) and wide threshold load simulation test, the influence of failure sensitive factors to cumulative damage/disengaging is studied; the cumulative damage mechanism of tunnel base structure is to be detected, thus the failure threshold of tunnel base structure is determined. Finally, the failure assessment and fatigue life prediction method for tunnel base structure is established, and the key technique of service performance evaluation and degradation control of heavy haul railway tunnel are formed.

重载列车反复冲击作用下隧道基底结构体系动力响应、基底结构累积损伤、围岩脱空形成演化机制以及损伤-脱空激励下基底结构服役性能是重载铁路隧道设计、运营及维护期间亟待解决的关键科学问题。.从重载铁路隧道基底结构与围岩相互作用动力分析入手，建立列车动载-隧道-围岩三维动力学模型，研究不同脱空条件下基底结构体系动力响应特征，提出不同地层所匹配的基底技术条件。引入围岩循环塑性本构，建立反复冲击作用下围岩动力学性能计算方法，探明基底脱空演化过程、成因机制。基于动载作用下混凝土劣化力学行为，建立混凝土循环粘塑性损伤模型，再现基底结构累积损伤-失效全过程。结合高精度、大比例（1∶10）、宽域值循环动载模拟试验，研究各失效敏感因子对基底结构损伤-脱空影响，揭示基底结构累积损伤劣化机理，确定其体系失效阈值点，建立损伤-脱空激励下基底结构失效评价及寿命预测方法，形成重载铁路隧道服役性能评价及劣化控制关键科学技术。

重载列车反复冲击作用下隧道基底结构体系动力响应、基底结构累积损伤、围岩脱空形成演化机制以及损伤-脱空激励下基底结构服役性能是重载铁路隧道设计、运营及维护期间亟待解决的关键科学问题。.从重载铁路隧道基底结构与围岩相互作用动力分析入手，建立列车动载-隧道-围岩三维动力学模型，研究不同脱空条件下基底结构体系动力响应特征，提出不同地层所匹配的基底技术条件。引入围岩循环塑性本构，建立反复冲击作用下围岩动力学性能计算方法，探明基底脱空演化过程、成因机制。基于动载作用下混凝土劣化力学行为，建立混凝土循环粘塑性损伤模型，再现基底结构累积损伤-失效全过程。结合高精度、大比例（1：10）、宽域值循环动载模拟试验，研究各失效敏感因子对基底结构损伤-脱空影响，揭示基底结构累积损伤劣化机理，确定其体系失效阈值点，建立损伤-脱空激励下基底结构失效评价及寿命预测方法，形成重载铁路隧道服役性能评价及劣化控制关键科学技术。