A Study On Support Structures And Control Technology Of Surrounding Rock Deformation In Soft Rock And Large-Section Tunnels Going Through Under Landside

The existence of the landslide and soft surrounding rock has brought a great challenge to the construction and operation of tunnel. How to effectively control the deformation of soft surrounding rock and ensure the safety of the tunnel-landslide system in the process of construction and operation is a problem for the builders and designers of tunnel engineering. Based on Weihe tunnel going through under landslide, through data survey, engineering analogy and numerical simulation method, monitoring measurement, research on control technology of surrounding rock deformation and tunnel-landslide interaction relation was carried out and an effective construction method to control the deformation of soft surrounding rock has been put forward finally. The main contents and conclusions are as follows:(1)Based on investigation and study of engineering literature, the characteristics and application status of excavation and supporting methods in soft-rock tunnels and similar tunnel engineering were summed up.(2)Through theory analysis for the impact on the stability of surrounding rock of excavation and supporting, combined with the engineering characteristics of Weihe tunnel and the mechanical properties of soft rock, what may happen after excavation were summed up and three kinds of construction method were put forward.(3)Three kinds of the construction method above were analyzed by numerical simulation method. The results showed that the method of "two-side drifting method-reinforced composite lining structure" had obvious advantages in controlling the deformation of soft surrounding rock and ensuring the safety of supporting structure. Therefore the construction method above was recommended as the best construction method of Weihe tunnel.(4)According to the results of the numerical simulation, this paper analysed the two formal interaction in tunnel-landslide system and indicated that the excavation had less effect on the landslide, while the extreme rainfall had a great influence on the stability of the landslide, which was the key to the safety control.(5)The results of the on-site monitoring measurement showed that the method of "two-side drifting method-reinforced composite lining structure" was suitable for Weihe tunnel. The comparison of results between the numerical simulation and the on-site monitoring showed that the numerical simulation method adopted was feasible, which could reflect the actual situation of the tunnel engineering.