Study On Approaching Construction Of Two-Tube Shield Tunnels By Centrifuge Model Test

The rapid development of economy in China speeds up the process of urbanization, continuously expands the size of cities, population density in the centre area of big cities and megalopolis. Crowded space, traffic congestion, slow pace of traffic forms a so-called "City Syndrome". For a long time, the expansion of urban transportation, infrastructure and capacity of major cities is based on the expansion of urban land use, but growth in population and living demands, the shortage of urban land use, has become the focus of contradictions. To achieve the sustainable development strategy, in addition to develop in high-altitude area, eyes are focused on the development and utilization of underground space, resulting in a large number of underground engineering and approaching construction of tunnels, which will inevitably cause complex relationship among the adjacent tunnels, putting forwards to a negative impact on tunnel construction.Underground tunnel excavation are more sensitive and vulnerable to disturbance, while the design and construction are also of no norms or standards, mechanical theory of all types of approaching excavation construction system has not elaborated. As a result, the reinforcement and safety measure are always excessively strict, based on which the construction is of much more difficulties. One way is to raise manufacturing cost and is likely to waste money. The other way is to take a risk to adapt blind countermeasure and results in safety problem. As the scale of city construction increases and shield method is used comprehensively, the study on influence rule and countermeasure of approaching excavation of shield tunnel are urgent affairs. Hereby study on approaching excavation of shield is of urgent needs.This dissertation proceed four groups of centrifugation model test on different position of double shield tunnels, by measuring ground settlements, wall rock pressure and lining internal force of shield tunnel in different construction course. Regularities of distribution of ground settlements, wall rock pressure and lining internal force is given based on the analysis of test data. This dissertation generalizes principium of centrifugation model test, design and execution of model, design for measurement system, fixing of test units and test results, based on which the safety control countermeasure of approaching excavation of shield tunnel is given and the problem in design and construction is solved, putting forwards to ensure project safety and economy, providing reference for similar project engineering.