某膨胀性围岩地层铁路隧道仰拱上拱原因分析及整治

某隧道长10 649 m,设计行车速度250 km/h,采用双块式无砟轨道结构,洞身通过地层主要为白垩系下统泥岩,局部夹薄层砂岩;在铺轨完成后,隧道局部段落基底出现不同程度上拱,导致无砟轨道道床板与仰拱填充表层脱空,仰拱及填充层开裂,轨道结构几何状态发生变化。通过现场调查、基底钻探、取样化验及局部破检探查等手段,查找、分析病害原因,根据病害情况及整治工期要求,分别采取仰拱返工、基底钻孔桩加固或锚杆加固等方式进行处理,如期完成了整治,确保线路开通运行。

Analysis of Causes and Improvement of Inverted Arch Heaving of a Railway Tunnel in Swelling Rock Formation

The FC tunnel of designed speed of 250 km/h and double-block ballastless track is 10 649 m in length and it located in inter-bedded strata of lower cretaceous mudstone and sandstone. After track-laying,various degrees of heaving appeared in local paragraphs,resulting in separation of track beds from surface layer of the invert,cracks in inverted arch and filling layer,and changes of track geometry. This paper analyzes the causes of the heaving of the inverted arch by means of field investigation,basal drilling,sampling test and local test probe. According to defects conditions and construction progress,inverted arch rework,basal drilled pile reinforcement and the reinforcement of bolt are used to treat the defects and ensure line service.