Abstract: The safety of the present supporting parameters for double-track tunnels on 350 km/h high-speed railways in China is calculated on the basis of the overall safety factor method of the tunnel support structure design, and the reasonable supporting for these tunnels are studied, in order to further optimize the supporting parameters of railway tunnels and advance the quantitative design of the supporting parameters. Furthermore, the concept and method for the optimization of the railway tunnel supporting parameters are suggested. The main conclusions drawn are as follows: (1) Only considering the surrounding rock pressure, the safety factor of the existing supporting parameters of the doubletrack tunnels on 350 km/h high-speed railways in China is relatively high, which has some room for optimization; (2) Reasonable supporting mode for double-track tunnels on 350 km/h high-speed railways in China is proposed; (3) It is suggested to optimize the support types according to different cover depths (groud stress) and groundwater conditions; (4) With different tunnel spans and stress/strength ratios, the reasonable supporting modes are different, and with the increase of the tunnel span, the ground stress and the stress/strength ratio, the necessity of adopting bolting support and the required support strength are also increasing.
Keywords: railway tunnel; overall safety factor method; support structure design; supporting parameter optimization
Source: Chinese Railways No.5 2021 Serial No.56
