STUDY OF EFFECTS OF BLAST ON SHALLOW LARGE-SPAN DOUBLE-LINKED-ARCH TUNNEL OF EXPRESSWAY
Li Fei1，Chen Weizhong1，Li Shucai1，2，Li Tingchun3
(1Key Laboratory of Rock and Soil Mechanics，Institute of Rock and Soil Mechanics，The Chinese Academy of Sciences， Wuhan 430071 China) (2 Research Center of Geotechnical and Structural Engineering，Shandong University， Jinan 250061 China) (3Shandong University of Science and Technology， Taian 271019 China)
Abstract：The section from Yichang to Enshi of the Shanghai—Chengdu expressway goes through mountainous area，and bridges and tunnels account for 50% of the length of the section. Shallow large-span double-linked-arch tunnel was adopted to save investment at the transition between bridges and tunnels. The spacing of tunnels is 5.5～25 m in the transition segments. The blasting of tunnel will have big influence on the stability of the adjacent tunnel. In this paper，the FDM software FLAC3D is employed to simulate the dynamic load on boreholes of the tunnels in different rock masses during blasting. The influence of the charge on the vibration velocity at key points，vibration velocity history and the state of remained rock masses are obtained from numerical results. A reasonable dynamite charge is suggested. The conclusions are valuable in design and construction of the tunnels.
2004, Vol. 23 
