Construction method for transverse expanding excavation conversion when tunnel section suddenly changes to large-span section

Abstract

The invention belongs to the field of tunnel engineering, and particularly relates to a construction method for transverse expanding excavation conversion when a tunnel section suddenly changes to a large-span section. According to the construction method, when the tunnel section enters the transition section of the suddenly-changed large-span section, firstly a preceding pilot tunnel is excavated, and then excavation expands towards the arch part of the suddenly-changed large-span section while excavating a following pilot tunnel; then 90-degree straight turning pilot tunnel expanding excavation is conducted in the side wall direction, during expanding excavation, a portal support is added to serve as temporary protection, and a portal cross beam is installed outside the large-span section contour line in the line direction; and after excavation is conducted to the position of a side wall arch foot of the large-span section, an annular arch frame of the large-span section is erected on the lower side of a portal cross beam at a time. According to the construction method, the portal support is large in operation space, high in safety and convenient to construct, meanwhile, the portal cross beam is arranged on the outer side of a main tunnel primary support arch frame, extension or erection of the main tunnel annular arch frame is not affected, the portal cross beam and upright end wall portal vertical supports at the junction of the two sections can serve as permanent primary supports, and the dismantling workload of the temporary portal is reduced.

Description

technical field

[0001] The invention belongs to the field of tunnel engineering, and more specifically relates to a construction method for lateral expansion and excavation conversion when the tunnel section suddenly changes to a large-span section, and more specifically relates to an excavation for lateral expansion and excavation conversion when the tunnel section suddenly changes to a large-span section , Support construction method. Background technique

[0002] In recent years, my country's railways have fully implemented the new development concept and paid more attention to the intensive use of underground space. New breakthroughs have been made in the construction technology of large-section tunnels and underground space engineering, and the design of variable diameter sections in large-section tunnels has gradually increased. Qiaopingshan Tunnel is a newly added tunnel for the station adjustment of Chongqing East Station on the East Ring Road of Chongqing Railway Hu...

Examples

Embodiment 1

[0053] Qiaopingshan Tunnel is a newly added tunnel for the station adjustment of Chongqing East Station on the East Ring Line of Chongqing Railway Hub. The tunnel is located in Banan District and Nan'an District of Chongqing. Since the main line of the East Ring Road needs to be connected to Chongqing East Railway Station, two large-span sections need to be set up in the cave, leading to the left connecting line of Chongqing East Station and the right connecting line of Chongqing East Station respectively. The starting and ending mileage of the large-span section of the right connecting line is DK43+ 150~DK43+304, 154m long. The first section is 19.72m wide x 14.29m high, and the second section is 24.52m wide x 16.13m high. This embodiment is the large-span transition construction of the first section of the right tie line of Chongqing East Railway Station, see figure 1 .

[0054] The bedrock of the lead-out connecting line section is Shaximiao Formation mudstone interbedded...

technical field

[0001] The invention belongs to the field of tunnel engineering, and more specifically relates to a construction method for lateral expansion and excavation conversion when the tunnel section suddenly changes to a large-span section, and more specifically relates to an excavation for lateral expansion and excavation conversion when the tunnel section suddenly changes to a large-span section , Support construction method. Background technique

[0002] In recent years, my country's railways have fully implemented the new development concept and paid more attention to the intensive use of underground space. New breakthroughs have been made in the construction technology of large-section tunnels and underground space engineering, and the design of variable diameter sections in large-section tunnels has gradually increased. Qiaopingshan Tunnel is a newly added tunnel for the station adjustment of Chongqing East Station on the East Ring Road of Chongqing Railway Hu...

Examples

Embodiment 1

[0053] Qiaopingshan Tunnel is a newly added tunnel for the station adjustment of Chongqing East Station on the East Ring Line of Chongqing Railway Hub. The tunnel is located in Banan District and Nan'an District of Chongqing. Since the main line of the East Ring Road needs to be connected to Chongqing East Railway Station, two large-span sections need to be set up in the cave, leading to the left connecting line of Chongqing East Station and the right connecting line of Chongqing East Station respectively. The starting and ending mileage of the large-span section of the right connecting line is DK43+ 150~DK43+304, 154m long. The first section is 19.72m wide x 14.29m high, and the second section is 24.52m wide x 16.13m high. This embodiment is the large-span transition construction of the first section of the right tie line of Chongqing East Railway Station, see figure 1 .

[0054] The bedrock of the lead-out connecting line section is Shaximiao Formation mudstone interbedded...

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