Rich Cement Rock Tunnel Construction Method Of The Research

With the development of society and technology, complicated geological environment can no longer stop human beings building various transportation facilities. However, how to construct underground projects properly and scientifically in the condition of water-abundant mudstone is an important yet difficult problem. Based on the Shuangfeng tunnel project in the line of Mu-sui, this thesis comparatively analyzes the deformation and force conditions of multiple construction methods via field monitoring, measuring and numerical simulating, and explores the construction method best suited for the standard of tunnel construction in the condition of water-abundant mudstone. The main work and outcome in this thesis are as follows: 1. It summarizes the previous studies and proposes a reasonable constitutive model. 2. It observes the field monitoring data and gets a conclusion via analyzing the deformation condition of surrounding rocks around the tunnels as well as the supporting condition that, the surrounding rocks around the tunnels which is just excavated have such features like a big deformation, a fast rate and a long time. 3. Through the comparative analysis of drainage and decompression project, it comes to the conclusion that, the decompression effect of two drainage wells is much better than that of one, but the two wells are interactional. Thus the arrangement of drainage wells must be properly considered so as to increase the decompression efficiency. 4. Through comparing the deformation condition of surrounding rocks and supporting condition, it concludes that the three-bench seven-step excavation method is more suitable for the tunnel construction in the condition of water-abundant mudstone than the two-bench excavation method. 5. Through comparatively analyzing the construction projects with or without temporary inverts, advanced small pipe supportings, or pipe shed supportings and the contrast of different step heights, it comes to the conclusion that, the temporary invert measure can effectively control the deformation condition of the surrounding rocks, though it has few influence on the force distribution of the supporting; the construction measure of advanced small pipe grouting is effective in controlling deformation, plus, it can turn the surrounding rocks on the top of the tunnels into an effective entirety, and decrease the distribution of plastic zones and the force peak of the supporting; the measure on pipe shed has an efficient effect on deformation controlling, and it can effectively decrease the force peak of the supporting as well as the force stable value after the supporting is balanced; by comparing the surrounding rock deformation, supporting force and the plastic zone distribution during the constructions of different top bar heights, it finds out that the top bar height of 3.5 meters is superior than the height of 4 meters or 3 meters. Thus the top bar height should be suitable, neither too long nor too short.