高速铁路隧道洞口危岩落石灾害评价方法及工程对策研究

A Study on Evaluation Method and Engineering Countermeasures of Dangerous Rockfall Disaster at Tunnel Portal of High-speed Railway

贵南高速铁路穿越岩溶地貌区,危岩落石成为影响隧道洞口安全的重要因素。本文将隧道洞口落石风险分为初始风险和残留风险,考虑隧道洞口仰坡坡度、危岩高度、危岩发育程度、危岩大小、落石冲击力、落石区与铁路工程的位置关系等关键因素,采用定性和定量相结合的方法构建初始风险评价方法;根据落石上道、隧道洞口结构局部破损、整体倾覆破坏3种落石灾害类型,结合落石运动规律计算和动力有限元数值分析,建立了Ⅰ期、Ⅱ期、Ⅲ期残留风险评估方法;将本文建立的危岩落石灾害全过程评价方法应用于贵南高速铁路隧道洞口工程中,确定了合理的工程措施及防护参数。

Guiyang-Nanning High-speed Railway passes through the karst landform area,and dangerous rockfall has become an important factor affecting the safety of tunnel portals· In this paper,the risk of rockfall at the tunnel portal is divided into initial risk and residual risk· Considering the key factors such as the gradient of the heading slope at the tunnel portal,the height of dangerous rocks,the development degree of dangerous rocks,the size of dangerous rocks,the impact force of rockfall,and the positional relationship between the rockfall area and the railway project,the initial risk assessment method is constructed by combining qualitative and quantitative methods· According to the three types of rockfall disasters:rockfall on the track,local damage of tunnel portal structure,and overall overturning damage,combined with the calculation of rockfall movement law and dynamic finite element numerical analysis,the residual risk assessment methods of Phase I,Phase Ⅱ,and Phase Ⅲ are established· The whole-process evaluation method of dangerous rockfall disaster established in this paper is applied to the tunnel portal project of Guiyang-Nanning High-speed Railway,and reasonable engineering measures and protection parameters are determined。