Study On The Stability Of Cross Of Underground Overpass Tunnel

As rapid development of China's economic and acceleration of urbanization process, the development and utilization of urban underground space is attaracting serious concern of more and more people. Among them,urban underground interchange is one form of development and utilization of underground space,which appeared in recent years. The urban underground Interchange cross paragraph often has the features of complex structure, small spacing, large excavation width and height, complex space relations . And the construction process will inevitably lead to the repeated stress redistribution of rock and the changes of the stress state of the tunnel structure itself.So it is very significant to concern about the variation of its mechanical behavior and the impact on the surrounding environment in the construction process.Based on the underground interchange tunnels project, which is in the planning, of Chongqing's Chaotianmen underwater overpass tunnels , the paper discusses simulatation of the site excavation to study the construction of underground interchange dynamic cross-section by researching a physical model of the mechanical construction of the underground tunnel interchange cross section. The comparsion with the numerical simulation results verifies the technical programs We have the following conclusions in this paper:â‘ Based on the underground interchange tunnels project, which is in the planning, of Chongqing's Chaotianmen underwater overpass tunnels,the paper determines the construction of the underground interchange tunnel's cross-section and mechanical parameters of the program and prepare the similar material which meets the requirements of similarity theory. In the meanwhile,we use an integrated highway tunnel and rock experimental system,which can make all-round physical simulation of the interchange cross-section of the underground construction, to obtaine cross-section of the construction of mechanical effectâ‘¡By the physical model test, we analyze the effect of its representation underwent excavation section of the hole around the first hole and underwent rock stress and displacement distribution, first hole has built support in the folder internal force distribution and the rock stress field may the surrounding stress field and displacement field and supporting internal forces in the dynamic changes of the construction process.â‘¢By the numerical analysis, we analyze and simulate the impact of test section's excavation corresponding to the representative underwent on the surrounding rock stress and displacement distribution, underwent Excavation's impact on the first hole surrounding rock stress and displacement distribution and the impact of the first underwent built hole's excavation on internal force distribution and support's stress field in the folder rock. So the comparision of the model test results with each other validation could provide reference for the practical engineering's design and construction.â‘£Based on the numerical analysis method, we analyze the surrounding stress field, displacement field and the internal forces in the cross-section of the whole construction process, where has been built support, of a number of sections in different spacing, by which we summary the impact of spacing change in cross-section of underground interchange on the construction's mechanical effect.