Large Cross Section Tunnel At Shallow Depth Excavation Deformation Control Researcl In Both The Urban Road

After entering the 21 st century,the number of urban underground space development in China has increased rapidly,and the system has been continuously improved.The overall scale and development speed of the development and utilization of underground space in metropolises have ranked in the advanced ranks of similar cities in the world.China has become the world's urban underground space development and utilization of power.Underground space will be the second space for human survival,and pointed out that the development and utilization of underground space has become an important measure to improve urban capacity,ease urban traffic and improve urban environment,and become an important way to solve China's sustainable development.With the development of urban underground space,more and more underpasses of existing super-shallow buried large-span tunnels appear,along with more and more flat-topped vertical wall tunnels,in order to increase the overall stability,control the road surface settlement,It is necessary to adopt the advanced support measures,the pipe shed support as the most commonly used support measures,the optimization of the pipe roof parameters can achieve the purpose of safety,but also reflect the economic principles.By using ABAQUS software to simulate the road surface subsidence under different excavation steps,the construction plan can be optimized,which has important guiding significance for the similar engineering under similar geological conditions.The main contents of this paper are as follows:(1)After field investigation and collection of relevant data,we have a certain understanding of the geology of Jiaozhou area in Qingdao.According to the geological conditions of Jiaozhou city,Qingdao,we study the initial supporting system of tunnel strength and deformation requirements of strata.(2)Aiming at the characteristics of ultra-shallow-buried,long-span,flattopped vertical wall structure,the auxiliary method of tunnel excavation is to support the large-span pipe support and soil reinforcement grouting,to study the arching effect in the pipe shed support,Spacing,and the spacing and size of the pipe shed to optimize the study of pipe shed caused by the construction process of surface subsidence.The reasonable control technology is put forward by analyzing the deformation mechanism of the tunnel with super-shallow-buried.(3)ABAQUS software was used to analyze the excavation order of different guide holes,and the stress-strain curves were obtained.The stress,deformation and surface subsidence of surrounding rock were analyzed during the tunnel excavation.Excellent construction parameters.In this paper,using finite element analysis combined with the formula,the parameters of the advance support in the area are obtained,and ABAQUS is used to simulate the influence of different excavation steps on the ground subsidence under the same condition of advance support,which is instructive to the construction sequence.