隧道下穿高速铁路路基风险分级及风险评价方法研究

Research on Risk Classification and Assessment Method for Tunnels Crossing under High-speed Railway Subgrade

隧道下穿高速铁路路基的安全风险主要取决于隧道施工引起的扰动范围和高速铁路路基的承载范围,根据高速铁路路基荷载在土层中附加应力的分布特征,将高速铁路路基承载区域划分为主承载区、次承载区和无承载区,根据隧道施工引起围岩的扰动特征,将隧道周边划分为松动区、扰动区和未扰动区,根据高速铁路路基承载分区和隧道扰动分区的位置关系进行下穿工程的风险分级,并确定下穿工程对高速铁路影响范围以及高速铁路影响的隧道区间范围。该方法成功应用于北京地铁14号线马家堡东路站—永定门外大街站区间隧道下穿京津城际铁路工程中。

As for a tunnel crossing under the high-speed railway subgrade,the safety risk depends mainly on the disturbance caused by tunnel construction and the load bearing range of high-speed railway subgrade.According to the distribution characteristics of the additional stress in the soil layer of the high speed railway subgrade,it divides the load bearing area of the high speed railway subgrade into the main load bearing area,the secondary load bearing zone and the non-load bearing zone.According to the disturbance characteristics of the surrounding rock caused by the tunnel construction,it divides the tunnel surroundings into the loose,disturbed and unperturbed areas.According to the location relationship between the load bearing zone of the high-speed railway subgrade and the disturbance zone of the tunnel,the risk classification of the under-crossing tunnel project is carried out.The influence range of the under passing tunnel on the high-speed railway and the influenced tunnel section due to the high-speed railway are determined.The method has been successfully applied to the risk assessment of the running tunnel from Majiapu East Road station to Yongding Menwai Street station on Beijing Metro Line 14,which passes under Beijing-Tianjin intercity railway.