Mountain Tunnel Monitoring Measuring And Back Analysis Of Rock Mechanics Parameter

In the context of overall highway construction, New Austrian Tunneling Method(NATM) is widely used in construction of highway tunnels. As the key of NATM,monitoring and measuring plays a vital role in the construction of the tunnel. The most important function of monitoring and measuring is that we can forecast and feedback the deformation and stress of surrounding rock, guide the construction, optimize the design and ensure construction safety and stability of surrounding rock and tunnel support lining structure based on monitoring data analysis and the necessary calculations and judgments.Taking into account the rock mass is uneven, discontinuous, the mechanics parameters gained through preliminary geological survey, laboratory test and local field test is not fully describe the nature of the rock mass. Given the displacement measurement is relatively accurate and easy, back-analysis of displacements has become a reliable method for determining rock mechanical parameters.Based on Guangdong Jie(Yang) Hui(Lai) highway Xiao Beishan No. 1 engineering,the research methods of field survey, prediction, regression analysis, numerical simulation and the golden section algorithm is adopted in the paper in order to carry out monitoring and measuring of tunnel construction, analyze the field monitoring data and explore reverse application. The main conclusions are as follows.First, for complex engineering geological conditions, construction methods and the type of support of the tunnel, an appropriate program of monitoring and measurement is put forward. Cumulative convergence curve of crown settlement and convergence periphery are drawn. And line type shape is consistent with excavation methods.Second, with the peripheral convergence measured data of ZK16 + 950 section, the gray prediction GM(1,1) model is carried out to analyze and predict the final deformation of surrounding rock and time of the secondary lining. Compared with regression analysisalgorithm, the results show that, the results of GM(1,1) model has higher precision than hyperbolic model.Third, based on the measured data of the K14 + 620 section, geotechnical parameter elastic modulus and cohesion is obtained through geotechnical engineering analysis software FLAC3 D, the golden section algorithm and back-analysis of displacements. The measured data of K14 + 640 section is selected to check accuracy and the calculation error is small.