高速铁路黄土隧道内轨道板上拱机理及整治方案

采用现场钻探、调查等方法对高速铁路黄土隧道运营前洞口段轨道板上拱现象进行分析,研究轨道板上拱机理,并给出相应处理方案.分析结果表明:中心水沟渗漏导致地基土含水率增大是轨道板上拱的主要原因;隧底湿陷性新黄土受水浸泡软化,仰拱填充层开裂,明洞段受其两侧暗洞段与路基桩板纵向挤压作用产生隆起;受水浸泡后,寒季冻涨作用使轨道板上拱.整治前隧道进口洞门段轨道板上拱最大值为12.9 mm,采用旋喷桩对隧道仰拱底予以加固并采取隧道疏排水措施后上拱现象消失,说明该措施可有效控制轨道板上拱变形.

Track Slab Upwarp Mechanism and Its Treatment Scheme for Loess Tunnel of High Speed Railway

By on-site drilling,investigation and other methods,the phenomenon of track slab upwarp at the loess tunnel portal section of a high speed railway before operation was analyzed,the upwarp mechanism of track slab was studied and a related treatment scheme was proposed.The analysis results show that the increase in the moisture content of the foundation soil caused by central gutter leakage is the main reason for track slab upwarp.The new collapsible loess at the tunnel bottom is softened by water immersion,the filling layer of the invert is cracked,and the open-cutting section is arched by the longitudinal compression of the under-cutting section and the pile foundation of the roadbed.The frost heaving in cold season also makes track slab arch up after soaking in water.Before remediation,the maximum value of track slab upwarp at the tunnel entrance portal section is 12.9 mm.However,the upwarp phenomenon disappeared after using the jet grouting pile to reinforce the tunnel invert bottom and taking the tunnel drainage measures,which indicates that the measure can effectively control the upwarp deformation of track slab.