Back-Analysis On The Structural Load Of Shallow-Buried Tunnel

With the rapid development of highway transportation construction, tunnel engineering, of which unsymmetrical loaded tunnel takes an important proportion, increased immediately. The size of the surrounding rock pressure during the design and construction of the unsymmetrical loaded tunnel determines the selection of the design of supporting parameters and construction method, so the solution of the surrounding rock pressure has a vital significance. As the background to Dahuyu tunnel of Wenxi-Jiyuan Expressway, The paper, used the study methods so model experiment and back analysis, relying on The Design and Construction Methods Research Subject of Bias Tunnel which sponsored by Shanxi Communication Department, studyed the distribution features and regularity of the surrounding rock pressure under different partial pressed angle and how the whole structure loads roundly. The main research contents and results are as follows:(1) Aimed at the characteristic that the load of lining is difficult to determine in the load-structure mode, the internal force back analysis method how to make sure the load of the bias shallow tunnel is studied and the corresponding calculation formulas which are suitable for it are derived out, while the relevant calculation program is developed, and combined with the testing data in the spot. The results of the sample calculation demonstrate that the procedures could satisfy the engineering demand.(2) As the background to Dahuyu tunnel, developing the model test of typical bias shallow tunnel section, study the dynamic distribution and deformation laws of the surrounding rock pressure、lining structural stress and ground surface settlement under different partial pressed angle in the tunnel construction, in order to analyze the stability of surrounding rock.(3) A back-analysis of the load of the supporting frameworks bearing is made by using the back-analysis program and the model test profit, and compared with the results worked out with the code for design of road tunnel. At the same time, the feasibility of an optimization scheme, which could be given used by back analysis results, was demonstrated. (4) Based on the influencing factor of the lining loading, the method how to ascertain the load of bias shallow tunnel is also discussed, and the corresponding formula of calculation of load have been drawn out, which can be referenced by the tunnel of the same type, by regression analysis.The above research results could provide scientific guide basis for the design and construction of the unsymmetrical loaded tunnel.