Monitoring Measurement And Data Inversion Analysis Of Large-span Tunnel With Weak Surrounding Rock

With the development of Chinese transportation, a large number of tunnel projectsto be approved and set into construction. Some of these tunnels excavated incomplicated geological conditions with soft surrounding rock. On the other hand, inorder to meet the demands of mass transportation, the excavation section is alsoincreased. As an important tool of the NATM, monitoring measurement has been widelyused. In this paper, based on the measurement of crown settlement, convergence,internal forces of steel arch, the rationality of the process of tunnel excavation and thestability of supporting structure were analyzed. At the same time, introduces theresearch status of the inverse analysis method, and combined with practical engineering,study the application of the inverse analysis in tunnel engineering.Based on the excavation of Jinpenwan tunnel, this paper briefly introduces theproject of Jinpenwan tunnel, clarifies purpose of tunnel monitoring measurement,meaning, and monitoring content. Combining the pictures for the crown settlement,surface subsidence, and surrounding rock pressure monitoring measurement items arediscussed in detail; the difficulties in the work of the Monitoring and Measurement areintroduced, and give specific solutions.Secondly, based on the vault settlement measurement data at locations K154+955and K155+161on the right line of Jinpenwan tunnel, regression analysis was conducted.The mechanism and change rule of these settlements were numerically studied in thisthesis. These results provided a comprehensive reference both to the selection of tunnelexcavation process and selection of optimal supporting time.Thirdly, according to the geological conditions at locations K155+101andK155+161on the right line of Jinpenwan tunnel and using commercial software ABAQUS, a three-dimensional FEM model is established. Based on this numericallymodel, the evolutions of surrounding rock deformation with the supporting time andexcavation space for each step during tunnel construction was numerically simulated.Finally, theoretical investigation was conducted to do the inverse analysis. Theoryof elastic foundation beam is employed to build the theoretical model. Considering thebasic parameters taken from Jinpenwan tunnel, pressures between surrounding rock andsupport structures is numerically analyzed by using this theoretical result. Comparisonsbetween the theoretical results and site measurement data are also presented to verifythe reasonability of this theoretical result. The variation of shotcrete structural forces isstudied in detail.All of results in this thesis have been applied in Jinpenwan project.