Landslide repairing structure of built pressure tunnel with vent pipe arranged in tunnel

Abstract

The utility model discloses a built pressure tunnel collapse repairing structure with a vent pipe arranged in the tunnel, which comprises a main tunnel and a branch tunnel, the main tunnel comprises a conventional main tunnel section and a bare rock collapse section, the branch tunnel comprises a steel lining plugging section and a conventional branch tunnel section, one end of the steel lining plugging section is connected with the conventional main tunnel section, and the other end of the steel lining plugging section is connected with the conventional branch tunnel section; comprising a ventilation system, the ventilation system comprises a ventilation pipe, the starting end of the ventilation pipe is located at the top of the bare rock collapse section, and the ventilation pipe is arranged along the wall of a main hole and extends to a branch hole; the bare rock collapse section is provided with an anchoring and shotcreting supporting structure. After the collapse is repaired, when water is introduced into the main hole, air in the hole top cavity of the collapse section can be exhausted along the ventilation system, and when the main hole is emptied and overhauled, the air valve at the tail end of the ventilation system can reversely provide air for the hole top cavity of the bare rock collapse section, so that a guarantee is provided for safe operation of the tunnel. The method has the advantages of being easy and convenient to construct, short in construction period, safe, reliable and low in investment, and the requirement for timely repairing collapse of the built pressure hydraulic tunnel can be met.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnels in water conservancy and hydropower projects, in particular to a collapse repair structure of a built - pressure tunnel with a ventilation pipe arranged inside the tunnel. Background Technique

[0002] With the continuous construction of water conservancy and hydropower projects in China, the tunnel project has developed rapidly. In water conservancy projects such as power generation water diversion, water supply and flood control, pressure tunnels are widely used. A considerable part of these pressure tunnels were built in the 20th century. At that time, in order to save investment, some tunnel sections with good surrounding rocks did not adopt shotcrete support or secondary lining. After years of operation of the un - supported and un - lined bare - rock tunnel sections, the rock mass may collapse due to softening when encountering water, or due to the large internal pressure in the tunnel and the air residue caused by the uneven inner surface leading to cavitation and then collapse. For the collapse of pressure tunnels, if no timely measures are taken for repair, the cavity at the top of the tunnel caused by the collapse will always retain a large amount of air that cannot be discharged during the operation period, which will further cause more serious cavitation phenomena and lead to a larger - scale collapse.

[0003] The tunnels for water supply, power generation water diversion and flood control are related to people's livelihood or power generation benefits. The time requirement for maintenance and repair is often very short. If the conventional secondary lining or steel lining method is used for repair, the construction time is often long and cannot meet the requirement of timely restoration of functions. Therefore, it is necessary to propose a measure with simple construction, short construction period, safety and reliability.

[0004] Based on this, this case is proposed. Content of the Utility Model

[0005] The purpose of the utility model is to provide a collapse repair structure of a built - pressure tunnel with a ventilation pipe arranged inside the tunnel, which has the characteristics of simple construction, short construction period, safety and reliability, and can meet the timely repair of the collapse of the built - pressure hydraulic tunnel.

[0006] In order to achieve the above purpose, the technical solution of the utility model is as follows:

[0007] A collapse repair structure of a built - pressure tunnel with a ventilation pipe arranged inside the tunnel includes a main tunnel and a branch tunnel. The main tunnel includes a conventional main tunnel section and a bare - rock collapse section. The branch tunnel includes a steel - lined sealing section and a conventional branch tunnel section. One end of the steel - lined sealing section is connected to the conventional main tunnel section, and the other end is connected to the conventional branch tunnel section. The steel - lined sealing section is closed by a steel plug during the operation period and opened as a traffic channel during the collapse repair period;

[0008] It includes a ventilation system. The ventilation system includes a ventilation pipe. The starting end of the ventilation pipe is located at the top of the bare - rock collapse section of the tunnel. The ventilation pipe is arranged along the tunnel wall of the main tunnel and extends to the branch tunnel, then passes through the steel - lined sealing section of the branch tunnel and reaches the conventional branch tunnel section to form a terminal; an anchor - shotcrete support structure is arranged in the bare - rock collapse section.

[0009] Furthermore, the shotcrete support structure in the bare rock collapse section extends to the conventional main tunnel sections in the upstream and downstream directions.

[0010] Furthermore, the shotcrete support structure includes initial shotcrete, wire mesh, shotcrete, systematic rock bolts, and random drainage holes. The initial shotcrete, wire mesh, and shotcrete are arranged from outside to inside on the sidewall of the tunnel. The systematic rock bolts are arranged along the radial direction of the tunnel, and the random drainage holes are arranged at the depressions and water seepage areas on the rock surface of the tunnel.

[0011] Furthermore, the ventilation system includes a pipe head and a pipe head fixing structure. The starting end of the ventilation pipe is connected to the pipe head. The pipe head fixing structure includes a pressing plate and bolts. The pressing plate presses and fixes the pipe head on the top of the bare rock collapse section, and the pressing plate is fixed to the top of the bare rock collapse section through bolts.

[0012] Furthermore, several pipe heads are provided. The several pipe heads are connected to the ventilation pipe through three-way or four-way joints. The several pipe heads are respectively arranged at different local highest points on the top of the bare rock collapse section, and the elevations of different local highest points are the same or close.

[0013] Furthermore, when the ventilation pipe is arranged along the wall of the bare rock collapse section, the ventilation pipe is buried in the wire mesh and shotcrete of the shotcrete support structure.

[0014] Furthermore, when the ventilation pipe is arranged along the wall of the conventional main tunnel section, it is fixed through the main tunnel grooving structure and / or pipe clamps. The main tunnel grooving structure includes grooving on the tunnel wall and a cement mortar layer. The ventilation pipe is arranged in the grooving on the tunnel wall and fixed by the cement mortar layer.

[0015] Furthermore, when the ventilation pipe passes through the steel lining plugging section of the branch tunnel, it is fixed through a drilling fixing structure. The drilling fixing structure includes a plugging body drilling and a cement mortar layer. The two ends of the plugging body drilling are respectively connected to the conventional main tunnel section and the conventional branch tunnel section. The ventilation pipe passes through the plugging body drilling and is fixed by the cement mortar layer;

[0016] and / or, by arranging the ventilation pipe at the bottom of the steel pipe in the steel lining plugging section and fixing it with a cement mortar layer, and drilling a hole at the end of the steel lining plugging section for the ventilation pipe to pass through.

[0017] Furthermore, a maintenance section and ventilation equipment are connected to the end of the ventilation pipe in the conventional branch tunnel section. The maintenance section includes a detachable union joint, a maintenance slot, and a maintenance cover plate. The union joint is located in the maintenance slot, and one end is connected to the ventilation pipe and the other end is connected to the ventilation equipment. The maintenance cover plate covers the maintenance slot;

[0018] The ventilation device includes a maintenance gate valve, an air valve, a drain valve and a connecting pipe. The front end of the connecting pipe is connected to a detachable union joint. The maintenance gate valve is installed on the pipe body of the connecting pipe. The rear end of the connecting pipe is divided into two paths, which are respectively connected to the air valve and the drain valve.

[0019] The ventilation pipe is arranged along the downward slope in the tunnel.

[0020] Furthermore, the part of the ventilation pipe arranged along the tunnel wall adopts a PE pipe, and the connecting pipe adopts a steel pipe.

[0021] The advantages of the present utility model are as follows:

[0022] 1. Safe and reliable: By adopting an anchor shotcrete support structure for the collapsed section of the existing pressure tunnel, the support stability of the collapsed section is ensured. Through the ventilation structure, the problem that a large amount of air remains in the cavity at the top of the collapsed section and cannot be discharged is effectively solved, avoiding the cavitation phenomenon caused by the remaining air in the cavity and leading to a larger range of collapses. Moreover, when the main tunnel needs to be emptied for maintenance, the ventilation structure can also supply air to the cavity at the top of the bare rock collapsed section in the reverse direction to prevent the rock mass at the top of the bare rock collapsed section from bearing additional adverse negative pressure when the main tunnel is drained, providing guarantee for the safe operation of the tunnel. At the same time, the construction of the support structure in the tunnel is carried out step by step from one side to the other side, which also ensures the safety during the construction period.

[0023] 2. Simple construction and short construction period, with little impact on project benefits: For the collapsed section, only the anchor shotcrete support structure and the ventilation system repair measures are taken. Although the ventilation system involves a relatively long line, the overall workload is greatly reduced compared with the conventional secondary concrete lining repair. Moreover, the cleaning of the collapsed rock debris, the anchor shotcrete support structure at the bare rock collapsed section and the construction of the ventilation system can be carried out simultaneously, effectively saving the repair time. It can save about more than 50% of the construction period compared with the conventional repair measures of first clearing the slag and then carrying out secondary concrete lining, and has little impact on the subsequent project benefits such as water supply, power generation and flood control.

[0024] 3. Low project investment: The investment in the anchor shotcrete support structure and the ventilation system mainly involved in the present utility model is relatively low. Compared with the conventional repair measures of first clearing the slag and then carrying out secondary concrete lining, it can save about more than 65% of the direct investment. If the indirect investment caused by subsequent project benefits such as water supply or power generation is considered, the investment saving ratio will be even higher. 4. Little impact on other maintenance work of the tunnel. The construction of the anchor shotcrete support structure and the ventilation system mainly involved in the utility model occupies less space and takes less time in the tunnel, and does not affect the implementation of other maintenance work of the tunnel. During the repair construction of the collapsed section, other positions of the tunnel can be maintained synchronously and corresponding repair measures can be taken. Description of the Drawings

[0025] Figure 1 It is a schematic plan view of the collapsed section repair structure of the existing pressure tunnel with a ventilation pipe installed in the tunnel in the embodiment;

[0026] Figure 2 It is a longitudinal sectional schematic diagram of a collapse repair structure of a built - pressure tunnel with a vent pipe installed in the hole in the embodiment;

[0027] Figure 3 It is Figure 1 and Figure 2 the A - A sectional schematic diagram of;

[0028] Figure 4 It is Figure 3 detail drawing A of;

[0029] Figure 5 It is Figure 4 the 1 - 1 sectional schematic diagram of;

[0030] Figure 6 It is Figure 5 the 2 - 2 sectional schematic diagram of;

[0031] Figure 7 It is Figure 5 the 3 - 3 sectional schematic diagram of;

[0032] Figure 8 It is Figure 1 and Figure 2 the B - B sectional schematic diagram of;

[0033] Figure 9 It is Figure 8 detail drawing B of;

[0034] Figure 10 It is Figure 1 the C - C sectional schematic diagram of;

[0035] Figure 11 It is Figure 1 and Figure 10 the D - D sectional schematic diagram of;

[0036] Figure 12 It is Figure 1 detail drawing C of;

[0037] Figure 13 It is Figure 1 , Figure 10 , Figure 12 the E - E sectional schematic diagram of;

[0038] Label description

[0039] 1 - Built - pressure tunnel; 11 - Main tunnel; 11a - Bare rock section; 11b - Bare rock collapse section; 11c - Collapsed rock debris; 11d - Shotcrete section; 11e - Concrete lining section; 12 - Branch tunnel; 12a - Steel lining plugging section; 12b - Conventional branch tunnel section; 2 - Anchor shotcrete support structure; 21 - Initial shotcrete; 22 - Steel mesh; 23 - Shotcrete; 24 - Systematic rock bolt; 25 - Random drainage hole;

[0040] 3 - Ventilation system; 31 - Vent pipe; 32 - Pipe head; 33 - Pipe head fixing structure; 34 - Main tunnel grooving fixing structure; 35 - Drilling fixing structure for the plugging section of the branch tunnel; 36 - Newly poured concrete floor of the branch tunnel; 37 - Maintenance section; 38 - Ventilation equipment; 33a - Pressure plate; 33b - Bolt; 37a - Demountable union; 37b - Maintenance slot; 37c - Maintenance cover plate; 38a - Maintenance gate valve; 38b - Air valve; 38c - Drain valve; 38d - Connecting steel pipe. Detailed implementation mode

[0041] The present utility model will be further described in detail below in conjunction with embodiments. It should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. in the text are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model.

[0042] As Figures 1 to 13 shown, this embodiment proposes a collapse repair structure for a built - in - pressure tunnel with a ventilation pipe inside the tunnel, including a built - in - pressure tunnel 1, an anchor - shotcrete support structure 2, and a ventilation system 3.

[0043] The built - in - pressure tunnel 1 includes a main tunnel 11 and a branch tunnel 12. In the plane, the main tunnel 11 and the branch tunnel 12 are arranged vertically. The main tunnel 11 includes a conventional main tunnel section (bare rock section 11a, shotcrete section 11d, and concrete lining section 11e), a bare rock collapse section 11b, and collapse rock debris 11c. The collapse rock debris 11c is located at the bottom of the bare rock collapse section 11b and needs to be cleared during the collapse repair. The branch tunnel 12 includes a steel - lined plugging section 12a and a conventional branch tunnel section 12b. One end of the steel - lined plugging section is connected to the main tunnel, and the other end is connected to the conventional branch tunnel section. The steel - lined plugging section 12a is closed with a steel blind head during the operation period and needs to be opened as a traffic channel during the collapse repair period.

[0044] The anchor - shotcrete support structure 2 includes initial shotcrete 21, steel mesh 22, shotcrete 23, systematic rock bolts 24, and random drainage holes 25. The initial shotcrete 21, steel mesh 22, and shotcrete 23 are arranged from the outside to the inside on the sidewall of the tunnel, and the systematic rock bolts 24 are arranged along the radial direction of the tunnel. The initial shotcrete 21 is used for the initial support of the bare rock collapse section 11b to reduce the risk of secondary collapse during the repair construction. The random drainage holes 25 should be arranged at the sunken and seeping parts of the rock surface. The range of the anchor - shotcrete support structure 2 at the bare rock collapse section 11b of the main tunnel 11 should be appropriately extended upstream and downstream to ensure the stability of the support.

[0045] The ventilation system 3 includes a ventilation pipe 31, a pipe head 32, a pipe head fixing structure 33, a main tunnel grooving fixing structure 34, a branch tunnel plugging section drilling fixing structure 35, a newly poured concrete floor 36 of the branch tunnel, an inspection section 37, and a ventilation device 38. The ventilation pipe 31 starts from the top of the bare rock collapse section 11b of the main tunnel 11 and is arranged along the tunnel wall to the branch tunnel 12, then passes through the steel lining plugging section 12a of the branch tunnel 12 and reaches the conventional branch tunnel section 12b.

[0046] Reference Figure 5 and Figure 7 , the starting pipe head 32 of the ventilation system 3 needs to be fixed by the pipe head fixing structure 33. The pipe head fixing structure 33 includes a pressing plate 33a and a bolt 33b. The pressing plate 33a presses and fixes the pipe head 32 on the top of the bare rock collapse section 11b, and the pressing plate 33a is fixed on the top of the bare rock collapse section 11b through the bolt 33b.

[0047] Reference Figure 5 , to enhance the stability of the ventilation pipe 31 arranged along the tunnel wall, when the ventilation pipe 31 is arranged along the tunnel wall of the bare rock collapse section 11b, it should be buried in the steel mesh 22 and shotcrete 23 of the anchor shotcrete support structure 2.

[0048] Reference Figure 9 , when the ventilation pipe 31 is arranged along the bare rock section 11a, the shotcrete section 11d, and the concrete lining section 11e of the main tunnel 11, the main tunnel grooving fixing structure 34 should be used for fixing. The main tunnel grooving fixing structure 34 includes a tunnel wall groove 34a and a cement mortar plastering layer 34b. The ventilation pipe 31 is arranged in the tunnel wall groove 34a and is fixed by the cement mortar layer 34b.

[0049] Reference Figure 10 and Figure 11 , when the ventilation pipe 31 is arranged along the steel lining plugging section 12a of the branch tunnel 12, the branch tunnel plugging section drilling fixing structure 35 should be used for fixing. The branch tunnel plugging section drilling fixing structure 35 includes a plugging body drilling 35a and a backfill cement mortar layer 35b. The two ends of the plugging body drilling communicate with the main tunnel 11 and the conventional branch tunnel section 12b respectively. The ventilation pipe 31 passes through the plugging body drilling 35a and is fixed by the cement mortar layer 35b.

[0050] Reference Figure 10 , Figure 12 and Figure 13, the vent pipe 31 is led to the conventional branch tunnel section 12b of the branch tunnel 12 and buried in the newly cast concrete floor slab 36 at the bottom of the tunnel. The vent pipe 31 is provided with a maintenance section 37 in the newly cast concrete floor slab 36 of the branch tunnel, and the end of the maintenance section is connected to the ventilation equipment 38. The maintenance section 37 includes a detachable union 37a, a maintenance slot 37b and a maintenance cover plate 37c. The union joint 37a is located in the maintenance slot 37b, and one end is connected to the vent pipe 31 and the other end is connected to the ventilation equipment 38. The maintenance cover plate 37c covers the maintenance slot 37b. When the vent pipe 31 is being maintained, the impurities in the vent pipe 31 can be discharged by unscrewing the detachable union 37a. The ventilation equipment 38 includes a maintenance gate valve 38a, an air valve 38b, a drain valve 38c and a connecting pipe 38d. The front end of the connecting pipe 38d is connected to the detachable union joint 37a, the maintenance gate valve 38a is installed at the pipe body of the connecting pipe 38d, and the rear end of the connecting pipe is divided into two paths and is respectively connected to the air valve 38b and the drain valve 38c. The maintenance gate valve 38a is usually in the open state and is only closed when the air valve 38b and the drain valve 38c need to be maintained.

[0051] After the collapse repair is completed, when the main tunnel 11 is in water operation, the residual air in the cavity at the top of the bare rock collapse section 11b can be discharged along the pipe head 32 of the ventilation system 3 to the end air valve 38b, thereby avoiding cavitation caused by the residual air in the cavity at the top of the bare rock collapse section 11b and further collapses. When the main tunnel 11 needs to be emptied for maintenance, the air valve 38b can also supply air to the cavity at the top of the bare rock collapse section 11b in the reverse direction to prevent the rock mass at the top of the bare rock collapse section 11b from bearing additional adverse negative pressure when the main tunnel 11 is drained.

[0052] To avoid residual water or sediment and other impurities in the vent pipe 31 from clogging the end air valve 38b, the detachable joint 37a of the maintenance section 37 should be opened before water is introduced, so that the impurities in the vent pipe 31 can drain along the slope. To prevent the end air valve 38b from being clogged due to the inability to completely drain the impurities in the vent pipe 31 by the above measures, when the main tunnel 11 is in water operation, while relying on the air valve 38b for exhaust, the drain valve 38c of the end ventilation equipment 38 should also be opened until clean and stable water flow is discharged from the drain valve 38c, indicating that the residual air in the cavity at the top of the bare rock collapse section 11b has been completely drained, and at this time the drain valve 38c can be closed. This measure of using the air valve 38b and the drain valve 38c for exhaust simultaneously not only increases the exhaust speed and shortens the exhaust duration, but also avoids the exhaust failure caused by the clogging of the air valve 38b alone, greatly increasing the reliability of exhaust.

[0053] The diameter and number of the vent pipes 31 in this embodiment can be adjusted according to the actual ventilation requirements to meet the engineering needs. At the same time, the material of the vent pipes 31 can be selected as PE pipes or steel pipes. The material of the vent pipes 31 arranged along the tunnel wall is preferably PE pipes, which are easier to bend than steel pipes and facilitate construction layout. The connecting pipe 38d of the end ventilation equipment 38 is preferably made of steel pipes. The PE pipes and steel pipes can be connected and converted through the detachable union 37a in the maintenance section 37.

[0054] Preferably, multiple pipe heads 32 can be provided at the starting end of the ventilation system 3. The pipe heads 32 can be connected to the vent pipes 31 through three-way or four-way joints. However, the multiple pipe heads 32 should be respectively arranged at different local highest points on the top of the bare rock collapse section 11b of the tunnel, and the elevations of different local highest points should be the same or close. This is to prevent water from entering in advance due to the lower elevation of a certain pipe head 32 when the main tunnel 11 is filled with water and exhausts air, resulting in the inability of the remaining pipe heads 32 to continue exhausting air. At the same time, the vent pipes 31 should be arranged with a downward slope from the pipe heads 32 to the maintenance section 37, and reverse slopes are strictly prohibited, so as to avoid partial impurities remaining in the vent pipes 31 and being unable to be discharged due to reverse slopes when the detachable union 37a is unscrewed for maintenance of the vent pipes 31.

[0055] When the vent pipes 31 are arranged along the main tunnel 11, in addition to being fixed by the grooving fixing structure 34, they can also be directly fixed to the tunnel wall by means of pipe clamps, etc., but the influence of the water flow velocity in the tunnel on the fixing stability should be considered. When the vent pipes 31 are arranged along the branch tunnel 12, in addition to being fixed by the drilling fixing structure 35 in the branch tunnel plugging section, they can also be arranged along the bottom of the branch tunnel plugging steel pipe and fixed by backfilling cement mortar, and then drilled and arranged from the end of the branch tunnel plugging steel pipe. However, the sealing welding at the intersection of the vent pipes and the end of the branch tunnel plugging steel pipe should be done well.

[0056] The collapsed rock debris 11c in the main tunnel 11 should be cleaned during the repair construction. The cleaning of the collapsed rock debris 11c, the shotcrete support structure 2 at the bare rock collapse section 11b, and the construction of the ventilation system 3 should be carried out simultaneously, which can effectively save the emergency repair time. At the same time, the shotcrete support structure 2 at the bare rock collapse section 11b should first be sprayed with primary concrete 21 on the overall collapsed surface to reduce the risk of secondary collapse during the repair construction. In addition, the shotcrete support structure should be gradually implemented from the extended support range on one side of the bare rock collapse section to the other side to ensure that the construction personnel can construct on a safer working surface.

[0057] The above embodiments are only used to explain the concept of the present invention, rather than limiting the protection scope of the rights of the present invention. Any non-substantive modification made to the present invention using this concept shall fall within the protection scope of the present invention.

Claims

1. A collapsing repair structure for an existing pressure tunnel with a ventilation pipe in the tunnel, comprising a main tunnel and a branch tunnel, wherein the main tunnel comprises a main tunnel section and a bare rock collapse section, and the branch tunnel comprises a steel lining plugging section and a branch tunnel section, wherein one end of the steel lining plugging section is connected to the main tunnel section, and the other end is connected to the branch tunnel section, and the steel lining plugging section is closed with a steel plug during operation and opened as a traffic passage during the collapse repair period; It is characterized in that It includes a ventilation system, which includes a ventilation pipe. The starting end of the ventilation pipe is located at the top of the bare rock collapse section. The ventilation pipe is arranged along the wall of the main cave and extends to the branch cave. Then, it passes through the steel lining sealing section of the branch cave and reaches the branch cave section to form a terminal. An anchor spraying support structure is set in the bare rock collapse section.

2. A structure for repairing collapse of an existing pressure tunnel with a ventilation pipe in the tunnel as claimed in claim 1, characterized in that: The anchor spraying support structure of the bare rock collapse section extends to the main tunnel section of the upstream and downstream sections.

3. A structure for repairing collapse of an existing pressure tunnel with a ventilation pipe in the tunnel as claimed in claim 1 or 2, characterized in that: The anchor-sprayed support structure includes primary sprayed concrete, steel mesh, sprayed concrete, system anchor rods and random drainage holes. The primary sprayed concrete, steel mesh and sprayed concrete are arranged from the outside to the inside on the side wall of the tunnel, the system anchor rods are arranged along the radial direction of the tunnel, and the random drainage holes are arranged in the depressions and seepage areas of the rock surface of the tunnel.

4. A structure for repairing collapse of an existing pressure tunnel with a ventilation pipe in the tunnel as claimed in claim 1, characterized in that: The ventilation system includes a pipe head and a pipe head fixing structure. The starting end of the ventilation pipe is connected to the pipe head. The pipe head fixing structure includes a pressure plate and bolts. The pressure plate presses and fixes the pipe head on the top of the bare rock collapse section. The pressure plate is fixed to the top of the bare rock collapse section by bolts.

5. A structure for repairing collapse of an existing pressure tunnel with a ventilation pipe in the tunnel as claimed in claim 4, characterized in that: There are several pipe heads, which are connected to the ventilation pipe through three-way or four-way joints. The several pipe heads are respectively arranged at different local high points on the cave top of the bare rock collapse section, and the elevations of the different local high points are consistent or close.

6. A structure for repairing collapse of an existing pressure tunnel with a ventilation pipe in the tunnel as claimed in claim 3, characterized in that: When the ventilation pipe is arranged along the cave wall of the bare rock collapse section, the ventilation pipe is buried in the steel mesh and sprayed concrete of the anchor spraying support structure.

7. A structure for repairing collapse of an existing pressure tunnel with a ventilation pipe in the tunnel as claimed in claim 1, characterized in that: When the ventilation pipe is arranged along the cave wall of the main cave section, it is fixed by the main cave groove structure and / or pipe clamps. The main cave groove structure includes a cave wall groove and a cement mortar layer. The ventilation pipe is arranged in the cave wall groove and fixed by the cement mortar layer.

8. A structure for repairing collapse of an existing pressure tunnel with a ventilation pipe in the tunnel as claimed in claim 1, characterized in that: When the ventilation pipe passes through the steel lining plugging section of the branch hole, it is fixed by a drilling fixing structure, the drilling fixing structure includes a plugging body drilling hole and a cement mortar layer, the two ends of the plugging body drilling hole are respectively connected to the main hole section and the branch hole section, the ventilation pipe passes through the plugging body drilling hole and is fixed by the cement mortar layer; And / or, the ventilation pipe is arranged at the bottom of the steel pipe of the steel lining plugging section and fixed by a cement mortar layer, and a hole is drilled at the end of the steel lining plugging section for the ventilation pipe to pass through.

9. A structure for repairing collapse of an existing pressure tunnel with a ventilation pipe in the tunnel as claimed in claim 1, characterized in that: The end of the ventilation pipe located in the branch tunnel section is connected with an inspection section and ventilation equipment. The inspection section includes a detachable joint, an inspection slot and an inspection cover. The joint is located in the inspection slot, and one end is connected to the ventilation pipe, and the other end is connected to the ventilation equipment. The inspection cover covers the inspection slot; The ventilation equipment includes a maintenance gate valve, an air valve, a drain valve and a connecting pipe, the front end of the connecting pipe is connected to a detachable union joint, the maintenance gate valve is installed at the pipe body of the connecting pipe, and the rear end of the connecting pipe is divided into two paths, respectively connected to the air valve and the drain valve; The ventilation pipe is arranged along the slope in the tunnel.

10. A structure for repairing collapse of an existing pressure tunnel with a ventilation pipe in the tunnel as claimed in claim 9, characterized in that: The portion of the ventilation pipe arranged along the cave wall is made of PE pipe, and the connecting pipe is made of steel pipe.

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