穿越土岩交界面的隧洞围岩变形数值模拟分析

Numerical Simulation Analysis of Surrounding Rock Deformation of Tunnel Crossing Soil-Rock Interface

针对强降雨导致穿越土岩交界面处隧洞围岩变形问题,依托某灌区工程总干渠1号隧洞,采用流固耦合理论的数值模拟方法,对该部位隧洞变形问题进行了模拟,并分析了围岩不同弹性模量、不同黏聚力、不同摩擦角、不同土岩交界面产状等参数对围岩变形的影响。结果表明:强降雨是隧洞变形的主要原因;拱顶沉降对弹性模量变化更敏感,地表沉降对黏聚力变化更敏感;土岩交界面倾角的变化对降雨后的围岩和地表沉降影响很大,地表沉降从0°时的5.82 mm变化到60°的37.16 mm,拱顶沉降从0°时的15.77 mm变化到60°时的26.17 mm。研究成果可以为类似工程选线布置和施工控制措施实施提供借鉴。

In view of the deformation of surrounding rock at the interface between soil and rock caused by heavy rainfall,relying on the No.1 tunnel of the main canal of an irrigation project,the numerical simulation method of fluid-solid coupling theory is used to simulate the deformation of the tunnel at this part,and the influence of parameters such as different elastic modulus,different cohesion,different friction angles and different soil-rock interface on the deformation of surrounding rock are analyzed.The results show that,(a)the heavy rainfall is the main cause of tunnel deformation;(b)the vault settlement is more sensitive to the change of elastic modulus,and the surface settlement is more sensitive to the change of cohesion;and(c)the change of inclination of soil-rock interface has a great influence on surrounding rock and surface settlement after rainfall,in which,the surface settlement changes from 5.82 mm at 0°to 37.16 mm at 60°,and the vault settlement changes from 15.77 mm at 0°to 26.17 mm at 60°.The research results can provide reference for route selection and construction control measures of similar projects.