Construction method of cross section-expanded loop type depressurizing portal for high-speed railway tunnel

Abstract

The invention relates to a construction method of a cross section-expanded loop type depressurizing portal for a high-speed railway tunnel, which comprises the following steps of: A, constructing an expanding section at the portal of a tunnel, wherein the cross-sectional area of the expanding section is 1.3-1.6 times larger than that of the tunnel; B, constructing lateral pilot tunnels at both sides of the portal of the tunnel, wherein the lateral pilot tunnels are parallel to the tunnel and are communicated with the outside, the lateral distance between each lateral pilot tunnel and the tunnel is 20-30m, and the cross-sectional area of each lateral pilot tunnel is 25-35% of the cross-sectional area of the tunnel; and C, constructing first, second and third transverse channels which transversely penetrate through the lateral pilot tunnels and the tunnel between the two lateral pilot tunnels. The portal of the railway tunnel constructed by using the method can effectively reduce micro pressure waves produced by a high-speed train moving into the tunnel, is easy to construct, is not influenced by the surrounding topography of the tunnel and has low construction cost.

Description

technical field [0001] The invention relates to a method for constructing a railway tunnel, in particular to a method for constructing an opening of a high-speed railway tunnel. Background technique [0002] With the opening of the Beijing-Tianjin Intercity Express Line, Zhengxi, and Wuhan-Guangzhou Passenger Dedicated Lines with a speed of 350km / h, it marks that my country's high-speed train technology is becoming more and more perfect, so that Chinese people can look forward to the travel problems that will plague 1.3 billion people in the near future can be completely resolved. Of course, with the increase of the speed of high-speed railway, it will also cause many new problems. When a train enters a railway tunnel at high speed, an initial compression wave will be generated in front of the train, and this wave will propagate forward along the tunnel. When the compression wave reaches the exit of the tunnel, it will be reflected to the entrance as an expansion wave. At t...

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Problems solved by technology

For extra-long tunnels, often because of the great depth of burial, the difficulty of shaft construction and high cost, this decompression method is difficult to popularize and use; 2. Enlarging the cross-sectional area of ​​the tunnel, by reducing the blocking ratio (the ratio of the cross-sectional area of ​​the train to the cross-sectional area of ​​the tunnel) ) to decompress, due to the adoption of this method, the amount of tunnel construction has increased greatly, and its construction cost is high, so its use is also limited; 3. To improve the air tightness of rolling stock, this method can only improve the ride in the compartment However, when the airtightness of the locomotive reaches a certain level, it is difficult to improve the airtightness, the technical difficulty is high, the maintenance cost is high, and the economy is poor, so it cannot be widely used.

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