A ventilation shaft for a large rescue station in a high-stress soft rock formation and a construction method thereof

Abstract

The present application provides a ventilation shaft for a large rescue station in a high-ground stress soft rock formation and a construction method thereof, which relates to the technical field of railway tunnels, including a main tunnel, wherein the main tunnel is provided with a reserved interface for connection with a connecting shaft, the connecting shaft includes a horizontal section and a vertical section that are interconnected, the horizontal section is connected to a smoke exhaust duct, and the vertical section is connected to the main tunnel via a reserved interface, and a reinforcement mechanism is provided at the reserved interface. By providing a reinforcement structure at the reserved interface, a group hole effect can be avoided, the possibility of collapse can be reduced, and the impact on the main tunnel can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of railway tunnels, and in particular to a ventilation shaft of a large rescue station in a high-ground stress soft rock formation and a construction method thereof. Background Art

[0002] In the design of the Yuntunbao Tunnel rescue station of the Chengdu-Lanzhou Railway, the smoke exhaust duct is connected to the main tunnel through a vertical shaft. The geological conditions of the Yuntunbao Tunnel are special. It is located on the right side of the Minjiang River (fault) in a north-south direction. The tunnel area is located in the terrain abrupt change zone on the east side of the Sichuan Basin and the Qinghai-Tibet Plateau. The geological structure belongs to the "A"-shaped structure of northwest Sichuan composed of the Longmenshan fold fault zone, the West Qinling fold fault zone, and the Minjiang fault. It has "four poles, three highs, and five complexities" (four poles: extremely strong terrain cutting, extremely complex and active structural conditions, extremely weak and broken lithological conditions, and extremely significant seismic effects). The geological characteristics of the project are as follows: three highs: high crustal stress, high seismic intensity, and high geological disaster risk; five complexities: complex tectonic movement history, complex structural features, complex and changeable flysch construction, complex geostress environment, and complex groundwater conditions. The lithology of the entire construction environment is phyllite, carbonaceous phyllite, and other rock strengths are less than 5MPa, which faces the disaster of large deformation of soft rock. At the same time, the intersection of the shaft and the main tunnel has obvious cave group effect, which increases the possibility and degree of large deformation of soft rock disasters, and even induces instability and collapse of surrounding rock and structure. Conventional shaft support measures and construction methods are difficult to ensure construction safety.

[0003] Application Contents

[0004] The first purpose of the present application is to provide a ventilation shaft for a large rescue station in a high-ground stress soft rock formation, which avoids the occurrence of a cluster hole effect, reduces the possibility of collapse, and reduces the impact on the main tunnel by providing a reinforcement structure at the reserved interface.

[0005] The second object of the present application is to provide a construction method for a ventilation shaft of a large rescue station in a high-ground stress soft rock formation, which adopts the setting of a temporary steel frame arch to avoid the impact of excavation on the main tunnel, and can complete the construction of the above-mentioned shaft safely and quickly.

[0006] The embodiments of the present application are implemented through the following technical solutions:

[0007] A ventilation shaft for a large rescue station in a high-ground stress soft rock formation is applied to the rescue station. The rescue station comprises a main tunnel and a smoke exhaust duct. The main tunnel is provided with a reserved interface for connecting to a communication shaft. One end of the communication shaft is connected to the smoke exhaust duct, and the other end of the communication shaft is connected to the main tunnel via the reserved interface. A reinforcement mechanism is provided at the reserved interface.

[0008] Furthermore, the communication shaft includes a horizontal section and a vertical section that are interconnected, the horizontal section is connected to the smoke exhaust duct, and the vertical section is connected to the main tunnel through the reserved interface.

[0009] Furthermore, the reinforcement mechanism includes a ring beam, which is arranged above the main tunnel and around the reserved interface.

[0010] Furthermore, the reinforcement mechanism includes a plurality of grouting steel flower pipes, and the plurality of grouting steel flower pipes are arranged around the reserved interface and the grouting steel flower pipes are arranged along the radial direction of the main tunnel.

[0011] Furthermore, the reinforcement mechanism includes a plurality of long anchor cables, which are arranged on both sides of the plurality of grouting steel flower pipes in the extension direction of the main tunnel.

[0012] Furthermore, the reinforcement mechanism includes a locking mouth, which is arranged above the main tunnel and around the reserved interface, and the locking mouth includes a plurality of steel frames arranged without gaps.

[0013] A construction method for a ventilation shaft of a large rescue station in a high-stress soft rock formation, the construction steps are as follows:

[0014] S0. Apply partial reinforcement mechanism at the reserved interface;

[0015] S1. A temporary steel frame arch is constructed in the main tunnel, wherein the temporary steel frame arch is arranged at the reserved interface section to support the secondary lining of the main tunnel of the section;

[0016] S2. Apply the remaining reinforcement mechanism at the reserved interface;

[0017] S3. Excavation of vertical shaft.

[0018] Furthermore, step S0 is to construct a ring beam from inside the main tunnel.

[0019] Furthermore, step S2 includes S2.1. constructing grouting steel pipes from the main tunnel.

[0020] Furthermore, step S2 includes S2.2. constructing a long anchor cable from the main tunnel.

[0021] Furthermore, in step S3, the excavation is carried out from the other end toward the reserved interface end, and the excavation method adopts mechanical excavation and / or weak blasting excavation. After excavating to the reserved interface, 5 steel frames are connected to form a lock.

[0022] Furthermore, before excavation, a protective shed is constructed in the main tunnel to prevent local falling of blocks and objects from being hit during the breach stage of the shaft bottom.

[0023] Furthermore, the method further comprises step S4. The steel frame and steel mesh are installed manually, concrete is sprayed using a small wet spraying machine, and the secondary lining is poured from bottom to top using a shaped steel curved mold.

[0024] The technical solution of the embodiment of the present application has at least the following advantages and beneficial effects:

[0025] This application avoids the occurrence of the cluster tunnel effect, reduces the possibility of collapse, and reduces the impact on the main tunnel by providing a reinforcement structure at the reserved interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the structure of a shaft provided in an embodiment of the present application;

[0028] Figure 2 A schematic diagram of excavation provided for an embodiment of the present application;

[0029] Figure 3 A cross-sectional view of a shaft construction provided in an embodiment of the present application;

[0030] Icons: 1-main tunnel, 2-smoke exhaust duct, 3-communication shaft, 31-horizontal section, 32-vertical section, 33-ring beam, 34-grouting steel flower pipe, 35-long anchor cable, 36-locking mouth. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0033] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0034] In the description of the present application, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the application is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0035] Example 1

[0036] like Figures 1 to 3 As shown, the present embodiment provides a ventilation shaft 3 of a large rescue station in a high-stress soft rock formation, which is applied to the rescue station. The rescue station includes a main tunnel 1 and a smoke exhaust duct 2. It should be noted that the main tunnel 1 is excavated and formed first, and a certain support is carried out. The main tunnel 1 is provided with a reserved interface for connecting with the communication shaft 3. One end of the communication shaft 3 is connected to the smoke exhaust duct 2, and the other end of the communication shaft 3 is connected to the main tunnel 1 through the reserved interface. A reinforcement mechanism is provided at the reserved interface; by providing the reinforcement mechanism at the reserved interface, it is avoided that when the shaft is excavated, the stress distribution of the structure is changed, the rock formation is changed, and finally collapse is caused, which affects the main tunnel 1. In the present embodiment, the communication shaft 3 includes a horizontal section 31 and a vertical section 32 which are interconnected. The horizontal section 31 is connected to the smoke exhaust duct 2, and the vertical section 32 is connected to the main tunnel 1 through the reserved interface. The above design can effectively avoid the smoke exhaust duct 2 and the main tunnel 1 being in the same vertical plane, and avoid the occurrence of a group cave effect.

[0037] In this embodiment, the reinforcement mechanism includes a ring beam 33, which is arranged above the main tunnel 1 and around the reserved interface. The above design can strengthen the strength of the arch of the main tunnel 1, so that the tunnel arch has sufficient strength to bear the stress release caused by excavation, and avoid deformation caused by stress release to affect the main tunnel 1; the reinforcement mechanism also includes a plurality of grouting steel flower pipes 34, which are arranged around the reserved interface and the grouting steel flower pipes 34 are arranged along the radial direction of the main tunnel 1. In other words, a plurality of grouting steel flower pipes 34 are arranged around the ring beam 33. Each grouting steel flower tube 34 is arranged along the radial direction of the main tunnel 1, and a plurality of grouting steel flower tubes 34 are constructed within the range of 100°-150° of the arch of the main tunnel 1. The above design is adopted to reinforce the rock layer around the interface of the vertical section 32, so that the rock layer at this location can withstand the stress release caused by partial excavation, reduce the possibility of collapse, and even if collapse occurs, it is only a small-scale collapse, and will not cause a large-scale collapse to affect the main tunnel 1. At the same time, the structure of the rock layer is changed. Even if collapse occurs, the rock layer basically moves along the preset direction (i.e., triangular shape). The reinforcement mechanism includes a plurality of long anchor cables 35. In the extension direction of the main tunnel 1, the plurality of long anchor cables 35 are arranged on both sides of the plurality of grouting steel flower pipes 34. The long anchor cables 35 are also arranged along the radial direction of the main tunnel 1. The angle between the long anchor cables 35 on both sides is 110°-160°. The above design can play a role in reinforcing the arch of the main tunnel 1, so that the arch can sufficiently support the stress change caused by the excavation of the shaft, can withstand the stress release from above, and change the rock formation. The structure can basically move along the preset direction (i.e., triangular shape) even if collapse occurs, which can play the role of automatically squeezing the rock stratum and automatically preventing the rock stratum from collapsing; the reinforcement mechanism includes a lock 36, which is arranged above the main tunnel 1 and around the reserved interface. The lock 36 includes a number of steel frames arranged without gaps. Since the connection between the shaft and the main tunnel 1 is the position where the stress is most concentrated, the above design is adopted to withstand the stress release caused by the excavation of the shaft, and at the same time cooperate with the grouting steel flower pipe 34 and the long anchor cable 35 to achieve rock stratum squeezing and automatically prevent collapse.

[0038] In some embodiments, the vertical section 32 is provided with a wall seat near the connection end with the main tunnel 1. The wall seat can prevent the weight of the secondary lining of the vertical shaft from being directly borne by the secondary lining of the main tunnel 1, which would cause great pressure on the secondary lining of the main tunnel 1 and thus create extremely high requirements for the secondary lining of the main tunnel 1, which would incur unnecessary costs. The above design utilizes the interaction between the wall seat and the rock formation to transfer part of the gravity of the secondary lining of the vertical shaft to the rock formation, which then releases the gravity of the secondary lining of the vertical shaft, thereby avoiding pressure on the main tunnel 1 and alleviating the pressure of the existing tunnel.

[0039] A construction method for a large-scale rescue station ventilation shaft 3 in a high-in-situ stress soft rock formation, the construction steps are as follows:

[0040] S0. Partial reinforcement mechanism is applied at the reserved interface. Specifically, a ring beam 33 is applied from the main tunnel 1. The timing of application is after the initial support and invert of the main tunnel 1 is completed;

[0041] S1. Construct temporary steel frame arches in the main tunnel 1. The arches are made of H200 heavy steel with a longitudinal spacing of 1m. The arches are connected longitudinally with I-beams. The temporary steel frame arches are set at the reserved interface section to support the secondary lining of the main tunnel 1 in this section. The specific location is within 5m on both sides of the shaft;

[0042] S2. Apply the remaining reinforcement mechanism at the reserved interface;

[0043] S2.1. A grouting steel tube 34 is applied from the main tunnel 1. Generally, the length of the grouting steel tube 34 is about 5m, which can be applied to most tunnels;

[0044] S2.2. Long anchor cables 35 are installed in the main tunnel 1. The length of the long anchor cables 35 is generally 10-15 m.

[0045] S3. Excavation of the shaft. Specifically, the excavation is carried out from the other end toward the reserved interface end. The excavation method is mechanical excavation and / or weak blasting excavation. The excavation is carried out while supporting. The excavation depth is 1m each time and the support is 1m. After excavation to the reserved interface, 5 steel frames are connected to form a lock 36. Usually, the lock buckle is made at a distance of 5m from the bottom of the shaft. The steel frame spacing of the lock buckle is 30-50cm. Usually, in implementation, since mechanical excavation is the safest construction method with the least impact on the main tunnel 1, the entire vertical section 32 needs to be excavated manually by mechanical means. If the vertical section 32 is long, considering the construction period and other issues, blasting excavation can be used far away from the connection. Specifically, drilling and blasting excavation is used above 10m from the bottom of the shaft, and mechanical excavation is used below 10m. In some special geological conditions, such as where multiple fault zones are intertwined, it has "four extremes, three highs and five complexities" (four extremes: extremely strong terrain cutting, structural The conditions are extremely complex and active, the rock conditions are extremely soft and broken, and the seismic effect is extremely significant; three highs: high crustal stress, high seismic intensity, and high geological disaster risk; five complexities: complex tectonic movement history, complex structural traces, complex and changeable complex rock construction, complex geostress environment, and complex groundwater conditions). The rock type of the entire construction environment is phyllite, carbonaceous phyllite, etc. Under the condition that the rock strength is less than 5MPa, blasting is very likely to cause large deformation, resulting in an impact on the main tunnel 1. Therefore, under such geological conditions, it is necessary to control the vibration velocity. In this embodiment, blasting excavation adopts weak blasting, also known as micro-vibration blasting; the applicant's research has found that, taking into account the distance between the heading and the main tunnel 1, the grade of the surrounding rock, etc., the single-point vibration velocity of blasting excavation is no more than 3cm / s, which can minimize the group hole effect and do not cause large stress adjustments, and avoid secondary deformation that affects the safety of existing structures.

[0046] S4. The steel frame and steel mesh are installed manually, and concrete is sprayed using a small wet spraying machine. The secondary lining is constructed using a fixed steel curved mold and poured from bottom to top. Usually, the spacing between the steel frames is about 60 cm / frame. The steel mesh is used in consideration of the soft geology. The steel frames of the vertical section 32 of the shaft are set horizontally with a horizontal spacing of 60 cm / frame, and the steel frames of the horizontal section are set vertically. It should be noted that the secondary lining of the shaft is constructed later than that of the main tunnel, and the timing of the construction of the secondary lining of the main tunnel can be before or after the excavation of the shaft. The construction of the secondary lining of the main tunnel before the excavation of the shaft makes the excavation of the shaft safer, but the deformation of the rock formation caused during the construction of the shaft is difficult to remedy. At the same time, it is difficult to reinforce the steel pipes and anchor cables on the basis of the secondary lining of the main tunnel. Therefore, the timing of the construction of the secondary lining of the main tunnel is selected according to the actual rock formation conditions.

[0047] During excavation, even if the vertical section 32 and the horizontal section are designed as arc-shaped transitions, it is recommended to excavate to a right-angle transition so that the wellhead lock 36 plate can be installed at the upper end of the vertical section 32 to ensure safety and normal construction.

[0048] Before excavation, that is, before starting step S3, a protective shed is constructed in the main tunnel 1 to prevent local falling blocks from causing objects to hit during the shaft bottom breach stage.

[0049] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A large-scale rescue station ventilation shaft in a high-stress soft rock formation, applied to a rescue station, the rescue station comprising a main tunnel and a smoke exhaust duct, the main tunnel being provided with a reserved interface for connection with a communication shaft, characterized in that: One end of the communication shaft is connected to the smoke exhaust duct, and the other end of the communication shaft is connected to the main tunnel through the reserved interface, and a reinforcement mechanism is provided at the reserved interface; The reinforcement mechanism includes a ring beam, which is arranged above the main tunnel and around the reserved interface; The reinforcement mechanism includes a plurality of grouting steel flower tubes, which are arranged around the reserved interface and along the radial direction of the main tunnel; the plurality of grouting steel flower tubes are applied within the range of 100°-150° of the main tunnel vault; The reinforcement mechanism includes a plurality of long anchor cables, which are arranged on both sides of the plurality of grouting steel flower pipes in the extension direction of the main tunnel; the angle between the long anchor cables on both sides is 110°-160°; The reinforcement mechanism comprises a locking port, which is arranged above the main tunnel and around the reserved interface, and the locking port comprises a plurality of steel frames arranged without gaps.

2. The ventilation shaft of a large rescue station in a high-stress soft rock formation according to claim 1 is characterized by: The communication shaft comprises a horizontal section and a vertical section which are interconnected, the horizontal section is connected to the smoke exhaust duct, and the vertical section is connected to the main tunnel through the reserved interface.

3. A method for constructing a ventilation shaft for a large rescue station in a high-in-situ stress soft rock formation as claimed in any one of claims 1 to 2, characterized in that: The construction steps are as follows: S0. Apply partial reinforcement mechanism at the reserved interface; S1. A temporary steel frame arch is constructed in the main tunnel, wherein the temporary steel frame arch is arranged at the reserved interface section to support the secondary lining of the main tunnel of the section; S2. Apply the remaining reinforcement mechanism at the reserved interface; S3. Excavation of vertical shaft.

4. The construction method of the ventilation shaft of a large rescue station in a high-stress soft rock formation according to claim 3 is characterized by: Step S0 is to construct the ring beam from inside the main tunnel.

5. The construction method of a large-scale rescue station ventilation shaft in a high-in-situ stress soft rock formation according to claim 4 is characterized by: Step S2 includes S2.

1. constructing grouting steel pipes from the main tunnel.

6. The construction method of a large-scale rescue station ventilation shaft in a high-stress soft rock formation according to claim 4 is characterized by: Step S2 includes S2.

2. constructing long anchor cables from the main tunnel.

7. The construction method of a large-scale rescue station ventilation shaft in a high-in-situ stress soft rock formation according to claim 3 is characterized by: In step S3, excavation is carried out from the other end toward the reserved interface end, and mechanical excavation and / or weak blasting excavation are used as the excavation method. After excavation to the reserved interface, 5 steel frames are connected to form a lock.

8. The construction method of a large-scale rescue station ventilation shaft in a high-in-situ stress soft rock formation according to claim 3 is characterized by: Before excavation, a protective shed is built in the main tunnel to prevent local falling blocks from causing objects to hit the bottom of the shaft during the breach stage.

Images