Abstract The impact force of rockfall, as the main accidental load, must be considered in the design for the open cut tunnel section and the open cut tunnel and shed tunnel sections specifically designed to prevent high-level collapse and rockfall. Due to the high research difficulty and complexity, the impact force of rockfall has always been a difficult problem to be solved in the industry, which determines that the current design of open cut tunnels and shed tunnels still relies mainly on experience analogy, supplemented by structural calculation and analysis. There are some problems in the current Guidelines for Design of Highway Tunnel (JTG D70-2010) that have not been discovered and corrected in a timely manner for the calculation of impact force of rockfall. This has led many scholars and designers in China to believe that the calculation results are severely distorted, resulting in small guiding significance of the Guidelines. In this paper, the abovementioned problems are corrected. Meanwhile, the issues not clearly specified in the Guidelines are analyzed and discussed, such as the difference between the contact force and the response force while the rockfall impacting the structure, the scope of action of the rockfall impact load, the effective length of the structure and the most unfavorable fortification object, and the corresponding modification suggestions are proposed. It is suggested that when the Guidelines is revised in the next edition, it should be more perfect, so as to better guide the calculation and design of the open cut tunnel and shed tunnel structures.
Abstract：
The impact force of rockfall, as the main accidental load, must be considered in the design for the open cut tunnel section and the open cut tunnel and shed tunnel sections specifically designed to prevent high-level collapse and rockfall. Due to the high research difficulty and complexity, the impact force of rockfall has always been a difficult problem to be solved in the industry, which determines that the current design of open cut tunnels and shed tunnels still relies mainly on experience analogy, supplemented by structural calculation and analysis. There are some problems in the current Guidelines for Design of Highway Tunnel (JTG D70-2010) that have not been discovered and corrected in a timely manner for the calculation of impact force of rockfall. This has led many scholars and designers in China to believe that the calculation results are severely distorted, resulting in small guiding significance of the Guidelines. In this paper, the abovementioned problems are corrected. Meanwhile, the issues not clearly specified in the Guidelines are analyzed and discussed, such as the difference between the contact force and the response force while the rockfall impacting the structure, the scope of action of the rockfall impact load, the effective length of the structure and the most unfavorable fortification object, and the corresponding modification suggestions are proposed. It is suggested that when the Guidelines is revised in the next edition, it should be more perfect, so as to better guide the calculation and design of the open cut tunnel and shed tunnel structures.
LI Liangpu1 YUAN Song1,
2 LIAO Peiyuan1 WANG Xibao1
.Suggestions on Revision of the Provisions for Calculating the Impact Force of Rockfall in Guidelines for Design of Highway Tunnel (JTG D70-2010)[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(3): 65-73
2023, Vol. 60 