Full-section Tunnel Construction Technique In Rock Masses And Its Support Alternatives

With the development of road , railway tunnel and city water-conveying tunnel, the construction and support technique of tunnel has been the hot area of research. The key techniques of full-section tunnel construction are discussed on the basis of the Dahuofang reservoir super long water-conveying tunnel project. TBM construction technique and support alternatives are studied by engineering analogy, experience summarizing, and numerical analysis. The main points of this dissertation are as follows:(1) The operating principle, the composition structure and the classification of TBM are studied. The advantage and disadvantage of TBM and those of drilling and blasting method are discussed and compared. The applicable condition and the working characteristic of TBM are also studied.(2) The design and the selection of the support type of TBM are discussed on the basis of the analysis of the key technique used in the construction support of TBM. The effect of anchor-shotcrete support and segment support are analyzed by FLAC method and Load-Structure method.(3) Based on the Dahuofang super long water-conveying tunnel project, the feasibility of the application of TBM in this project is discussed;the factors that affect the layout of TBM are analyzed;the construction area of TBM and NATM are determined;the key factors of the selection of the TBM style are discussed thoroughly;the construction plan and parameters of TBM are given.(4) According to the characteristics of the Dahuofang reservoir water-conveying tunnel, the combined support of anchort-shotcrete and prefabricated segment is given. The internal force and the stability of the support lining and the wall-rock are analyzed. The rationality of the support structure design is proved.