活动地裂缝对高速铁路简支梁桥危害机理及工程措施研究

China suffers the most serious ground fissure hazards in the world: the ground fissures are widely distributed, and its frequence of occurrence as well as extent of disasters are increased year by year. All of these threaten high-speed railways which are under large scale construction in our country seriously. Based on the research of ground fissures in Shanxi fault basin, taking ground fissure area which is crossed by the now commenced Da-Xi passenger dedicated line as research object, using physical model test ,numerical simulation and theoretical analysis combined with calculation as research methods, this project mainly focuses on the research of high-speed railway bridge engineering damage mechanism caused by active ground fissure, reveals deformation and failure mechanism of simple supported bridge and track with different spans under the action of ground fissure,and propose a reasonable span for simple supported bridge, which provides bridge engineering as well as ground fissure hazards prevention in ground fissure area crossed by Da-Xi passenger dedicated line with theoretical basis and technical guidance. The achievement of this project not only has important reference value for the prevention of high speed railway ground fissure hazard in other area, but also enrich our research on ground fissure hazards, especially research on prevention and control of high speed railway ground fissure hazards, which has important theoretical and practical significance.

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，对我国当前正在大规模建设的高速铁路构成了严重威胁。本项目以山西断陷盆地地裂缝灾害为研究背景，选择已开工建设的大西客运专线穿越地裂缝段为研究对象，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，重点开展活动地裂缝对高速铁路桥梁工程危害机理研究。力求通过本项目的研究，揭示地裂缝活动作用下不同跨度的简支梁桥及轨道变形破坏的机理，并提出简支梁桥的合理跨度，为大西客运专线跨越地裂缝带的桥梁工程及地裂缝灾害防治提供理论依据和技术指导。项目研究成果不仅对其它穿越地裂缝发育区的高速铁路灾害防治具有重要参考价值，而且将丰富我国地裂缝灾害研究，尤其是高速铁路地裂缝灾害防治研究，具有重要的理论意义和工程实际意义。

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，对我国当前正在大规模建设的高速铁路构成了严重威胁。本项目以大西客运专线穿越地裂缝段为研究对象，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，重点开展活动地裂缝对高速铁路桥梁工程危害机理研究。项目研究成果不仅对其它穿越地裂缝发育区的高速铁路灾害防治具有重要参考价值，而且将丰富我国地裂缝灾害研究，尤其是高速铁路地裂缝灾害防治研究，具有重要的理论意义和工程实际意义。.在区域地质背景分析的基础上，调查并分析了大西客运专线典型地区和地段的地裂缝及其工程灾害特点、地裂缝活动变形特征。.发明了一种地裂缝危害模拟方法和一种地裂缝活动对高铁桥梁危害的模拟装置。通过高铁桥梁穿越地裂缝带的物理模型试验和实体工程数值模拟计算，揭示了高铁桥梁桥基、箱梁及轨道的受力变形机制：①随着地裂缝位错量的增加，地表逐渐出现了错台；上盘桩所受上部荷载变小，下盘桩所受荷载明显增大；桩身弯矩不随地裂缝变化而变化。②地裂缝活动作用下，桥梁结构中上盘紧靠地裂缝的箱梁与桥墩发生了脱空；位于上盘的紧靠地裂缝的两箱梁接头发生张开。地裂缝活动对跨越地裂缝的箱梁影响较大，而对未跨越地裂缝的箱梁影响较小。.通过对不同跨度高铁桥梁跨越地裂缝带的数值计算，分别分析了地层整体位移场及应力应变，箱梁位移场及应变及桩基础位移场、轴力和弯矩的变化规律及相互关系，提出了选择常规孔跨较为合理。.提出了桥梁跨越地裂缝时，应采取如下措施：桥梁采用常规孔跨简支结构；桥梁基础适当加强，桩基础采用桩身通长配筋；采用可调高支座，支座预埋套筒和加长螺栓；简支结构的横向和纵向活动支座均布置在靠近地裂缝的一侧，必要时两侧增加双固定支座桥墩，同时加大桥墩垫石尺寸，预留发展空间；地裂缝附近的简支梁梁端底板纵向均预留槽口，以备顶梁时作为操作空间。