高速铁路浅埋隧道入口危岩落石分析及防护设计

Protection Design of High-speed Railway Shallow Buried Tunnel Entrance for Dangerous Rock Fall

为了分析危岩落石对铁路隧道的影响并提出相应防护措施,以某高速铁路浅埋隧道入口为研究区域,对所在范围内的危岩落石进行评价,先采用人工调查法确定危岩落石分布范围,后对收集数据的发生概率和危害程度进行评分,根据分值进行危险级别的划分,最后对高风险级别以上危岩落石,取典型危岩体进行稳定性计算,并采用Rockfall软件对危岩落石的崩塌轨迹进行数值模拟。研究结果表明,晏家塆隧道入口附近存在典型危岩体4处,碎石散落区5处,均为高风险区域,危岩体欠稳定;rockfall模拟结果发现,危岩体以倾倒方式破坏,并以89°倾向崩塌,崩塌最大水平位移为89.8 m,最大落差为84.21 m,最大冲击能为109.32 kJ,最大弹跳高度为5.69 m。根据以上情况,建议采用清除危岩落石,在入口处设置被动防护网和明洞等工程措施。

In order to analyze the impact of dangerous rock fall on the tunnel and propose corresponding protective measures,a high-speed railway shallow buried tunnel entrance was adopted as the study area and the evaluation of dangerous rock fall within the scope was developed.Firstly,manual survey method was used to determine the distribution range of dangerous rock fall,and then the probability of occurrence and the degree of hazard of the collected data was calculated according to the score for the confirmation of the risk level.Finally,for the high-risk level above the dangerous rock fall,a typical dangerous was calculated and the collapse trajectory of the rockfall was numerically simulated by using Rockfall software.The result shows that,there are 4 typical rockfalls and 5 debris scattering areas near the entrance of Yanjiawan tunnel,all of them are high-risk areas and the rockfalls are unstable;rockfall simulation results show that the rockfalls are damaged by tipping and collapse with 89°tendency,the maximum horizontal displacement of the collapse is 89.8 m,the maximum drop is 84.21 m,the maximum impact energy is 109.32 kJ and the maximum bouncing height is 5.69 m.Therefore,it is recommended to adopt engineering measures such as removing dangerous rock fall,setting passive protection net and open hole at the entrance.