基于震后复旧工程的断裂带区域轨道设计借鉴

Reference for Track Design in Fault Zone Areas Based on Post-Earthquake Restoration Engineering

针对兰新高铁震后轨道伤损评估及复旧工程设计无章可依且无经验可借鉴的情况,基于震后复旧工程设计,对断裂带区域轨道结构选型与设计有关经验进行分析。除大梁隧道F5断裂外,钢轨扭曲变形及扣件破坏主要发生在硫磺沟大桥上,是由地震荷载下桥梁支座螺栓剪断后梁体移位落梁,相邻梁体变形差异大引起。道床板存在局部1~2 m范围碎裂,主要与地震横波、纵波传递过程中的叠加有关。个别段落出现轨道不平顺超限的情况,主要是受线下基础类型和地质条件差异等因素影响。震后复旧工程应首先基于基准点的测设与平差开展区域性线形重构与拟合;断裂带区域轨道设防长度根据有砟轨道养护维修最小段落长度确定,不能满足震后轨道结构的调整需求,建议结合预估错位量及线路拟合范围、轨道调整能力综合确定;近断裂带区域无砟轨道建议采用无挡肩轨枕,在地震情况下使扣件弹条或者锚固螺栓发生破坏,而轨枕保持完整,以降低震后复旧工程难度及代价;为确保特殊条件下的整治效果,建议采取特种整治措施。

In response to the lack of regulations and no experience to draw upon for assessing post-earthquake track damage and restoration design for the Lanzhou-Xinjiang High-speed Railway,this study analyzed relevant experiences in the selection and design of track structures in fault zone areas based on post-earthquake restoration engineering.Apart from the F5 fault in the Daliang Tunnel,rail distortion and fastening failures mainly occurred on the Liuhuanggou Bridge.This was caused by the shear failure of the bridge support bolts under seismic loading,leading to displacement and dropping of the beams,with significant deformation differences between adjacent beams.The track bed slab exhibited localized fractures in the range of 1 to 2 meters,mainly related to the superposition during the transmission of seismic P-waves and S-waves.Instances of excessive track irregularity were noted in certain sections,primarily influenced by variations in subgrade types and geological conditions.The post-earthquake restoration should begin with the measurement and adjustment of benchmark points to facilitate regional linear restoration and fitting.The protective length of the track in the fault zone should be determined based on the minimum maintenance length for ballasted tracks.To meet the adjustment requirements of post-earthquake track structure,it was recommended to comprehensively determine this length based on estimated misalignment and the line fitting range,as well as the track adjustment capacity.In fault zone areas,it was advisable to use shoulderless sleepers for ballastless tracks,which would allow for the failure of fastening springs or anchoring bolts under seismic conditions while keeping the sleepers intact,thereby reducing the difficulty and cost of post-earthquake restoration.To ensure effective remediation under special conditions,it was recommended to adopt specialized remediation measures.