高速铁路跨地裂缝带路基动力响应机制及长期沉降研究

China is the most typical country suffered from serious ground fissure hazards in the world, ground fissures are so widely distributed in China, and the engineering hazards induced by ground fissure are rising gradually every year, which poses a serious threat to the large-scale construction of high-speed railway in the context of the implementation of China national strategy “One belt, One road”. In this project, taking the ground fissure hazards in Feiwei basin as research background, the Da-xi (from Datong to Xi’an) high-speed railway crossing many active ground fissure zones is taken as the research object, to study the dynamic response and long-term settlement of high-speed railway subgrade crossing ground fissure zone under the long term vibration load of train with large-scale model test, numerical simulation and theoretical analysis. Through this project research, the dynamic response attenuation laws of high-speed railway subgrade crossing ground fissure zone, dynamic interaction of ground fissure and subgrade, and the influential mechanism of foundation stiffness and groundwater level change on dynamic response of subgrade will be revealed and prediction model and calculation method of accumulation deformation and long-term settlement of subgrade crossing ground fissure under the action of long term vibration load of train will be proposed. The project research achievements will provide theoretical basis and technical support to subgrade design, long-term stability assessment, disease prevention and treatment of high-speed railway crossing the ground fissure zone in the ground fissure development regions of China.

我国是世界上地裂缝灾害最为严重的国家，地裂缝分布十分广泛，其发生频率和灾害程度逐年加剧，对我国当前“一带一路”国家战略实施背景下的大规模高速铁路建设带来了严重威胁。本项目以汾渭盆地地裂缝灾害为研究背景，以大西客运专线高速铁路穿越地裂缝带为研究对象，采用物理模型试验、数值模拟和理论分析计算相结合的方法，重点开展列车长期振动荷载作用下跨地裂缝带高速铁路路基动力响应及长期沉降研究。力求通过本项目的研究，揭示列车长期振动荷载作用下跨地裂缝带路基动力响应衰减规律、地裂缝-路基动力响应的互馈机制以及地基刚度和地下水位变化对高速铁路路基动力响应的影响机制，提出列车长期振动荷载作用下跨地裂缝带路基累积变形与长期沉降预测模型和计算方法，为我国地裂缝发育区高速铁路跨越地裂缝带的路基设计、长期稳定性评估以及病害处治提供理论依据和技术支持。

我国是世界上地裂缝灾害最为严重的国家，地裂缝分布十分广泛，其发生频率和灾害程度逐年加剧，对我国当前“一带一路”国家战略实施背景下的大规模高速铁路建设带来了严重威胁。本项目以大西客运专线高速铁路穿越我国地裂缝最为发育的地区—汾渭盆地为研究背景，采用野外调查、地质钻探、现场测试、室内土工试验与物理模型试验、数值模拟和理论分析计算相结合的技术手段，系统开展列车长期振动荷载作用下跨地裂缝带高速铁路路基动力响应及长期沉降研究。通过本项目的研究，首次揭示了列车长期振动荷载作用下跨地裂缝带路基动力响应衰减规律、地裂缝-路基动力响应的互馈机制以及地基刚度和地下水位变化对高速铁路路基动力响应的影响机制；厘定了高铁列车振动荷载作用下天然地基和复合地基路堤穿越地裂缝上、下盘动力响应的影响范围及临界影响深度，发现地裂缝场地动力响应具有明显的“上盘放大效应”即上盘动力响应要大于下盘；构建了列车长期振动荷载作用下跨地裂缝带路基累积变形分析模型与长期沉降计算方法，提出了跨地裂缝带高铁路基加固技术措施；自主研发了一套高速铁路跨地裂缝带动力响应模拟试验系统，为高速铁路跨地裂缝、断层等地质软弱面（带）路基、桥梁结构动力响应及工程致灾机理与病害防治研究提供了重要试验平台，具有较好的应用前景。上述研究成果为我国地裂缝发育区高速铁路跨越地裂缝带的路基设计、长期稳定性评估、沉降控制与病害防治提供了重要的理论依据和技术支持。