Research On Dynamic Evaluation Method Of Surrounding Rock Construction Safety Of Highway Tunnel

In adopting the New Austrian Tunneling Method of the construction of mountain highway tunnel, the tunnel engineering of the safe and stable state monitoring and evaluation is very important, but the amount of monitoring data is not timely and effective used to guide the design and construction, and so far, domestic haven’t form a widely accepted method of highway tunnel construction safety evaluation. So how to effectively monitor measuring data processing, a reasonable evaluation of highway tunnel construction safety, further to guide tunnel construction become a need to solve the problem.Based on the YunHu no.1tunnel monitoring measurement data, during construction of highway tunnel safety evaluation method is studied. The main research contents and research results were as follows:(1) Based on advance geological forecast of the situation of the surrounding rock detection level of surrounding rock of highway tunnel design stage has carried on the correction, the use of advanced geological forecast revision levels of the basic flow of the surrounding rock and the fixed point.(2) On the basis of field monitoring measurement data, according to rock mass, buried depth range of different statistical deformation law of surrounding rock, and carries on the regression analysis of monitoring data, get the function relation between the displacement and excavation of the time.(3) According to the measured displacement variation, with incremental displacement back analysis method based on genetic algorithm for surrounding rock mechanics parameters for the inversion, the inversion result is the equivalent elastic modulus and poisson’s ratio of surrounding rock.(4) Using the inversion of the mechanical parameters of surrounding rock, the three-dimensional simulation of tunnel excavation.①In the process of tunnel excavation, the tunnel vault sink, peripheral convergence, and the relationship between the time tunnel buried depth, excavation were studied, obtained the deformation law of surrounding rock and the displacement of surrounding rock deformation, deformation and displacement of surrounding rock is established and the buried depth, excavation time binary prediction function.②Primary support for tunnel safety coefficient distribution rule is studied, the different excavation method, the location of the minimum safety factor of under different buried depth, displacement and the minimum safety factor are established binary prediction function.(5) According to the results of the study are to establish the safety of the surrounding rock comprehensive dynamic evaluation method, and the application of this method in practical engineering to do the validation, proved that this method can effectively evaluate the safety of surrounding rock.