Study Of Strata Deformation Caused By The Three-bench Method Construction Of Large-span Tunnel And Construction Control Under Weak Surrounding Rock Geological Conditions

In recent years, with the development of the cause of China's transportation, a large amount of highway tunnel rail tunnel construction, various construction method of continuous use to tunnel construction, in numerous tunnel construction method, three steps method with its unique advantages and used by people concern. In order to further study the method, this article emphatically from the stratum deformation research.Based on the state highway rebuilding project 108 tunnel as the background, south village more meticulous study the method in construction stage, and analyzed the measured data of different interval period when three steps construction method of excavation cause strata distortion law, analyses the construction step of stratum deformation affected sequence.By using the finite element numerical simulation software "Midas", and will be simulated results and the measured data are compared and analyzed.Affecting vaults settlement, respectively, convergence factors, put forward the summing rules three steps should be paid attention to in the construction method of some problems.1) Using numerical calculation software in a "GTS-Midas"to in the calculation model of each of the three steps method to reflect the construction step, realization and sequence site construction step sequence roughly the same calculation simulation, according to the calculated results of three steps method was studied each construction stage of rules and features of strata distortion.2) According to the measured data contrast analysis of various excavation interval, three steps excavation construction when soil strata distortion rule, characteristics and reasons and puts forward the construction of some items should be paid attention to.3) Combined construction and monitoring results, analysis of the construction step sequence stratigraphic deformation affected.