Numerical Simulation And Intelligent Prediction Of Approaching Excavation In City Subway Station

In the 21st century, with the appliance and development of underground space-avaluable resource, urban metro as a convenient, fast and environmental rail transport of modern cities, is being built in recent years. However geologic body which metro tunnel was located has the characteristics of complexity and variance, the influence of construction process to the surrounding rock and structures should not be ignored. On the basis of constructing the new tunnel safely, ensure the existing structures maintain normal utilization is a problem which need to be solved in the tunnel construction.By the means of calculation analysis and field monitoring, this paper, combined with the construction method of each excavation stage in the Xianggong street station of Dalian metro line 2, makes a scrutiny into excavation stability of the station and the influence of excavation on adjacent pile foundations, and then guides construction.Combined with the geological survey information and field construction monitoring data, the paper analyzed stability of surrounding rock with different construction methods based on the numerical simulation of construction process. In the simulation of center cross diagram method, combined with triaxial compression test on calcareous slate, the Mohr-Coulomb model and the Strain-Softening model are used to calculate the bearing capacity of excavated tunnel. After the simulation of the Strain-Softening model got the progressive failure pattern of tunnel roadbed bearing capacity, the paper compared the results of two methods with each other. In the numerical simulation of covered excavation method, according to orthogonal design principle, the paper designs the orthogonal design plan, and then the finite difference software FLAC3D is used to calculate. Using the extreme difference analysis for statistical analysis, the comparison of the difference of the sensitiveness of physical and mechanical parameters in the various soil formations was made in this paper.In the construction process, the remote automation monitoring system was constructed to monitor their real-time data as well as manipulate data at any moment. The monitoring data is used for roll forecast by the means of GA-SVM. The results show that:Intelligent forecast results are consistent with field monitoring results. This method forecast a collapse accident. Through grouting to strengthen strata, the safe excavation was achieved.The research of Xianggong street station provides the theory and engineering basis for adjacent construction theory, and has important guidance to field construction, and also provides reference and guidance for similar constructions.