Combined structure and construction method of diversion tunnel and venting tunnel for ultra-high rockfill dam

Abstract

The invention discloses a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam and a construction method, comprising a diversion tunnel and a venting tunnel, wherein the venting tunnel comprises a venting tunnel non-combined section, a venting tunnel intersection section and a venting tunnel combination section, wherein the venting tunnel non-combined section, the venting tunnel intersection section and the venting tunnel combination section are connected, wherein the diversion tunnel comprises a diversion tunnel inlet discharge control gate chamber and a diversion tunnel non-combined section, wherein the diversion tunnel inlet discharge control gate chamber is connected to the diversion tunnel non-combined section, wherein the diversion tunnel non-combined section and the venting tunnel non-combined section intersect at the venting tunnel intersection section and merge with the venting tunnel combination section to form a Y shape. The invention has the advantages that different structures can be formed at different operation stages, thereby realizing different functional effects, the structural arrangement is simple to realize, the construction is convenient, and the multiple functions of flood season diversion, ecological water supply during water storage period, and water storage discharge control are realized at the same time; a shared section combination structure can greatly reduce the engineering volume, save engineering investment, and shorten the construction period.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and hydropower engineering, and in particular to a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam and a construction method. Background Art

[0002] At present, my country's southwest region is building and planning a number of 200m-class high rockfill dam hydropower projects. These ultra-high rockfill dams are located in high mountain valleys and have complex geological conditions, high water heads, and large discharges. In order to ensure the dry land construction conditions of the entire dam, the construction diversion adopts a year-round tunnel diversion scheme in which the corresponding diversion tunnels are excavated in the mountain. The water flow control during the construction period has the characteristics of large flood flow and complex water storage procedures. The construction diversion mostly adopts the layered arrangement of diversion tunnels to meet the requirements of flood control, discharge control, and water storage.

[0003] As a temporary structure, diversion tunnels are often combined with permanent structures to achieve the purpose of significantly reducing investment and saving construction time. At present, the combination of diversion tunnels and vertical shaft flood discharge tunnels is mostly used in ultra-high rockfill dam projects. For example, the Houziyan, Lianghekou, Shuangjiangkou and other ultra-high rockfill dams have adopted this method, while there are fewer cases of combining diversion tunnels with emptying tunnels. Xiangyangqiao Reservoir, Pubugou and other projects have adopted the layout of combining diversion tunnels with emptying tunnels, but the diversion tunnels of these projects are mainly used for flood control, and their design elevations are similar to the design elevations of emptying tunnels, so they can adopt the layout of combining the diversion tunnels with the entire body of the emptying tunnels. However, in the ultra-high rockfill dam project, the diversion tunnels are arranged in layers, including the initial, middle and late diversion tunnels. The late diversion tunnels not only have the function of flood control, but also need to satisfy the ecological flow discharge during the water storage period and control the water level rise rate through discharge control to ensure the safety of the ultra-high rockfill dam body. At this time, in order to meet multiple functional requirements, the design elevation of the diversion tunnel inlet and the design elevation of the emptying tunnel have a large difference in height, and the full tunnel body cannot be used.

[0004] Therefore, it is necessary to design a combined structure of a diversion tunnel and a draining tunnel for an ultra-high rockfill dam, in order to solve the defect that the existing technology cannot meet the multiple functional needs of ultra-high rockfill dams such as diversion during flood season, ecological water supply during water storage period, and water storage and discharge control. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the prior art cannot meet the multiple functional requirements of super-high rockfill dams, such as diversion during flood season, ecological water supply during water storage period, and water storage and discharge control.

[0006] The present invention is achieved through the following technical solutions:

[0007] A diversion tunnel and venting tunnel combined structure for an ultra-high rockfill dam comprises a diversion tunnel and a venting tunnel, wherein the venting tunnel comprises a venting tunnel non-combined section, a venting tunnel intersection section and a venting tunnel combination section, wherein the venting tunnel non-combined section, the venting tunnel intersection section and the venting tunnel combination section are connected, wherein the diversion tunnel comprises a diversion tunnel inlet discharge control gate chamber and a diversion tunnel non-combined section, wherein the diversion tunnel inlet discharge control gate chamber is connected to the diversion tunnel non-combined section, wherein the diversion tunnel non-combined section and the venting tunnel non-combined section intersect at the venting tunnel intersection section and merge with the venting tunnel combination section to form a Y shape.

[0008] The existing technology is to use a combination of diversion tunnels and vertical shaft spillway tunnels in ultra-high rockfill dam projects, which cannot meet various functional requirements. The height difference between the design elevation of the diversion tunnel inlet and the design elevation of the discharge tunnel is large, and the full tunnel body combination cannot be used.

[0009] The end of the non-combined section of the diversion tunnel of the present invention is the end of the non-combined section of the emptying tunnel, and is also the starting end of the combined section of the emptying tunnel. The three form a "Y"-shaped combined structure. By setting the "Y"-shaped diversion tunnel and the combined structure of the emptying tunnel, the diversion tunnel and the emptying tunnel cooperate with each other, and different structures can be formed in different operation stages, thereby realizing different functional roles. The structural layout is simple and the construction is convenient. It realizes the multiple functions of flood season diversion, ecological water supply during the water storage period, and water storage and discharge control, which well meets the multiple needs of the ultra-high rockfill dam project. In the case of having corresponding functions, sharing a combined section structure can greatly reduce the amount of engineering, save engineering investment, and shorten the construction period.

[0010] The invention preferably provides a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam, wherein a venting tunnel accident lock chamber and a venting tunnel working lock chamber are arranged on the non-combined section of the venting tunnel, and the venting tunnel accident lock chamber is arranged in front of the venting tunnel working lock chamber;

[0011] The front mentioned in the present invention is the front in the water flow direction.

[0012] The invention preferably provides a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam, wherein a permanent plug is provided at a non-combined section of the diversion tunnel, and a control sluice chamber at the inlet of the diversion tunnel is provided in front of the permanent plug;

[0013] The diversion tunnel inlet control leakage gate chamber is located at the front end of the diversion tunnel along the water flow direction.

[0014] The invention preferably provides a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam, wherein a diversion tunnel branch is provided in a non-combined section of the diversion tunnel, and the diversion tunnel branch is provided at the rear side of a permanent plug;

[0015] The permanent plug is located in front of the branch tunnel of the diversion tunnel along the water flow direction.

[0016] The invention preferably provides a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam, wherein a lower branch tunnel of the venting tunnel is provided on the venting tunnel combined section, and the lower branch tunnel of the venting tunnel is at the front end of the venting tunnel combined section.

[0017] The invention preferably provides a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam. Before the main flood season, a No. 1 plugging body and a No. 2 plugging body are arranged at the intersection of the end of the non-combined section of the venting tunnel and the non-combined section of the diversion tunnel. The No. 1 plugging body and the No. 2 plugging body are on the non-combined section of the venting tunnel, the No. 2 plugging body is on the outside of the intersection, and the No. 1 plugging body is in front of the No. 2 plugging body.

[0018] The sum of the lengths of the No. 1 plugging body and the No. 2 plugging body meets the requirement of blocking the high water level during the main flood season. The purpose of setting the No. 1 plugging body is that due to the flow through the diversion tunnel during the main flood season, the water level is high, and pressurized flow is generated in the diversion tunnel, which causes huge pressure on the side wall. By setting the No. 1 plugging body, the safety of the venting hole structure located near the intersection section when the diversion tunnel is flowing during the main flood season is effectively guaranteed; the purpose of setting the No. 2 plugging body is to ensure the smooth flow of water in this section and avoid the damage to the structure caused by the turbulent water flow.

[0019] The shape of the No. 2 plugging body meets the flow state requirements of the diversion tunnel, and the flow surface direction is parallel to the diversion tunnel side wall direction. The diversion tunnel and the emptying tunnel combine to form a diversion channel during the main flood season. Through hydraulic calculations, the design of the entire channel can meet the flow requirements of the main flood season, thereby meeting the flow requirements of the diversion tunnel during the main flood season.

[0020] The invention preferably adopts a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam. Before the main flood season, a B1 plugging body is arranged in the branch tunnel of the diversion tunnel;

[0021] The purpose of providing the B1 plugging body is to ensure that water does not enter the branch hole of the diversion tunnel, so that it can flow smoothly in the diversion channel.

[0022] The invention preferably provides a diversion tunnel and a lower branch tunnel for a super-high rockfill dam. Before the main flood season, a B2 plugging body is provided in the lower branch tunnel of the emptying tunnel;

[0023] The purpose of providing the B2 plugging body is to ensure that water does not enter the construction branch hole, so that it can flow smoothly in the diversion channel.

[0024] A construction method for a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam, comprising the following steps:

[0025] S1: rock mass excavation, completion of diversion tunnel and drain tunnel penetration construction;

[0026] S2: Complete the lining construction of the diversion tunnel and the venting tunnel, and complete the construction of the diversion tunnel inlet control lock chamber, the venting tunnel accident lock chamber and the venting tunnel working lock chamber;

[0027] S3: Before the main flood season, the No. 1 and No. 2 plugging bodies were cast;

[0028] S4: During the main flood season, the combined section of the diversion tunnel and the drain tunnel forms a diversion channel for the main flood season, meeting the flow requirements during the main flood season.

[0029] S5: After the flood season, the diversion tunnel will be opened for controlled discharge and water storage according to the flow of the reservoir. When the reservoir water level reaches the target water level, the diversion tunnel will be closed.

[0030] S6: After the gate is lowered in the diversion tunnel, the B1 plugging body is removed, the permanent plugging is completed, the permanent plugging is backfilled and grouting is performed, the permanent plugging joints and consolidation grouting are performed, the tunnel is cleaned and the construction facilities are removed, and then the diversion tunnel branch is plugged again;

[0031] S7: While S6 is being carried out, the No. 1 plugging body, No. 2 plugging body and B2 plugging body are removed, and the lining surfaces of the plugging sections of the No. 1 plugging body and No. 2 plugging body are repaired; the plugging body construction of the C plugging body at the end of the non-combined section of the diversion tunnel is completed, the tunnel is cleaned and facilities are removed, the diversion tunnel branch tunnel 11 is blocked, and the construction of the branch tunnel is connected to the outside, which will affect other buildings. After blocking, future troubles are isolated.

[0032] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] 1. The combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam of the present invention can form different structures in different operation stages to achieve different functional roles. The structural arrangement is simple and the construction is convenient. It has multiple functions of diversion during the flood season, ecological water supply during the water storage period, and water storage and discharge control, and satisfies the multiple needs of the ultra-high rockfill dam project.

[0034] 2. The combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam of the present invention can share a section of the combined structure while having corresponding functions, which can greatly reduce the amount of engineering work, save engineering investment, and shorten the construction period.

[0035] 3. A combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam according to the present invention, Figure 2 The purpose of setting up the No. 1 plugging body is: due to the flow of the diversion tunnel during the main flood season, the water level of the reservoir is high, which causes pressurized flow in the diversion tunnel, causing huge pressure on the side walls. By setting up the No. 1 plugging body, the structural safety of the venting tunnel located in the cross tunnel section during the flow of the diversion tunnel during the main flood season is effectively guaranteed.

[0036] 4. A combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam according to the present invention, Figure 2The purpose of setting the No. 2 plugging body is to ensure the smooth flow of water at the intersection and avoid the damage of the structure caused by the turbulence of the water flow. The purpose of setting the B1 plugging body and the B2 plugging body is to ensure that the water does not enter the diversion branch tunnel and the branch tunnel under the venting tunnel, so that the water flows smoothly in the diversion channel.

[0037] 5. A combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam according to the present invention, Figure 3 Through the simultaneous construction of two working faces, the reconstruction construction period of the venting tunnel after the diversion tunnel is closed is effectively guaranteed; by setting up the C plugging body, the functional conversion of the permanent structure is realized. Its body design meets the requirements of the venting tunnel flow, and finally meets the requirements of the ultra-high rockfill dam for the multi-functionality of the hydraulic tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0039] Figure 1 It is a cross-sectional view of the combination of a "Y"-shaped diversion tunnel and a drain tunnel.

[0040] Figure 2 This is a partial enlarged schematic diagram of the B1 blocking body and the B2 blocking body.

[0041] Figure 3 This is a partial enlarged schematic diagram of the C plugging body.

[0042] 1-diversion tunnel, 2-diversion tunnel lock chamber, 3-permanent plug, 4-venting tunnel accident lock chamber, 5-venting tunnel working lock chamber, 6-No. 1 plugging body, 7-No. 2 plugging body, 8-diversion tunnel non-combined section, 9-venting tunnel non-combined section, 10-venting tunnel combined section, 11-diversion tunnel branch tunnel, 12-B1 plugging body, 13-venting tunnel, 14-venting tunnel intersection section, 15-B2 plugging body, 16-venting tunnel lower branch tunnel, 17-C plugging body. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0044] Example 1

[0045] like Figure 1-3As shown, the present invention is a diversion tunnel 1 and a venting tunnel combined structure for an ultra-high rockfill dam, comprising a diversion tunnel 1 and a venting tunnel, wherein the venting tunnel comprises a venting tunnel non-combined section 9, a venting tunnel intersection section 10 and a venting tunnel combination section, wherein the venting tunnel non-combined section 9, the venting tunnel intersection section 10 and the venting tunnel combination section are connected, wherein the diversion tunnel 1 comprises a diversion tunnel 1 inlet discharge control gate chamber and a diversion tunnel non-combined section 8, wherein the diversion tunnel 1 inlet discharge control gate chamber is connected to the diversion tunnel non-combined section 8, wherein the diversion tunnel non-combined section 8 and the venting tunnel non-combined section 9 intersect at the venting tunnel intersection section 10 and merge with the venting tunnel combination section to form a Y shape. The end of the non-combined section 8 of the diversion tunnel is the end of the non-combined section 9 of the venting tunnel, and it is also the starting end of the combined section of the venting tunnel. The three form a "Y"-shaped combined structure. By setting the "Y"-shaped diversion tunnel 1 and the combined structure of the venting tunnel, the diversion tunnel 1 and the venting tunnel cooperate with each other to form different structures in different operation stages, thereby realizing different functional roles. The structural layout is simple and the construction is convenient. It realizes the multiple functions of flood diversion, ecological water supply during the water storage period, and water storage and discharge control, which well meets the multiple needs of the ultra-high rockfill dam project. In the case of having the corresponding functions, sharing a combined section structure can greatly reduce the amount of work, save project investment, and shorten the construction period.

[0046] Example 2

[0047] like Figure 1-3 As shown, this embodiment is based on Embodiment 1, and a drain hole accident chamber 4 and a drain hole working chamber 5 are provided on the drain hole non-combination section 9, and the drain hole accident chamber 4 is provided in front of the drain hole working chamber 5; the front mentioned in the present invention is the front in the water flow direction.

[0048] The non-combined section 8 of the diversion tunnel is provided with a permanent plug 3, and the inlet control leakage gate chamber of the diversion tunnel 1 is arranged in front of the permanent plug 3; the inlet control leakage gate chamber of the diversion tunnel 1 is at the front end of the diversion tunnel 1 along the water flow direction.

[0049] The non-combined section 8 of the diversion tunnel is provided with a diversion tunnel branch hole 11, and the diversion tunnel branch hole 11 is arranged at the rear side of the permanent plug 3; the permanent plug 3 is in front of the diversion tunnel branch hole 11 along the water flow direction.

[0050] A lower branch hole 16 of the vent hole is arranged on the vent hole combination section, and the lower branch hole 16 of the vent hole is at the front end of the vent hole combination section; before the main flood, No. 1 plugging body 6 and No. 2 plugging body 7 are arranged at the intersection of the end of the vent hole non-combination section 9 and the diversion hole non-combination section 8, and the No. 1 plugging body 6 and No. 2 plugging body 7 are on the vent hole non-combination section 9, the No. 2 plugging body 7 is on the outside of the intersection, and the No. 1 plugging body 6 is in front of the No. 2 plugging body 7.

[0051] The lengths of the No. 1 blocking body 6 and the No. 2 blocking body 7 meet the requirements of blocking the high water level during the main flood season. The purpose of setting the No. 1 blocking body 6 is that during the main flood season, the diversion tunnel 1 flows and the water level is high, and pressurized flow is generated in the diversion tunnel 1, which causes huge pressure on the side walls. By setting the No. 1 blocking body 6, the structural safety of the venting hole in the diversion tunnel 1 during the main flood season is effectively guaranteed; the purpose of setting the No. 2 blocking body 7 is to ensure the smooth flow of water in this section and avoid the damage to the structure caused by the turbulent water flow.

[0052] The shape of the No. 2 plugging body 7 meets the flow state requirements of the diversion tunnel 1, and the flow surface direction is parallel to the side wall direction of the diversion tunnel 1. The diversion tunnel 1 and the emptying tunnel combine to form a diversion channel during the main flood season, thereby meeting the flow requirements of the diversion tunnel 1 during flood season.

[0053] Before the main flood season, a B1 plugging body 12 is provided in the diversion tunnel branch 11; the purpose of providing the B1 plugging body 12 is to ensure that water does not enter the construction branch tunnel, so that water flows smoothly in the diversion channel.

[0054] Before the main flood season, a B2 plugging body is provided in the lower branch hole 16 of the vent hole; the purpose of providing the B2 plugging body is to ensure that water does not enter the construction branch hole, so that it can flow smoothly in the diversion channel.

[0055] Example 3

[0056] like Figure 1-3 As shown, this embodiment is based on Embodiment 1 and Embodiment 2, and is a construction method for a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam, comprising the following steps:

[0057] S1: rock mass excavation, completion of diversion tunnel 1 and drain tunnel penetration construction;

[0058] S2: Complete the lining construction of diversion tunnel 1 and venting tunnel, complete the construction of diversion tunnel 1 inlet control lock chamber, venting tunnel accident lock chamber 4 and venting tunnel working lock chamber 5;

[0059] S3: Before the main flood season, the No. 1 plugging body 6 and the No. 2 plugging body 7 were cast;

[0060] S4: During the main flood season, the diversion tunnel 1 and the drain tunnel combined section 10 form a main flood season diversion channel to meet the main flood season flow requirements.

[0061] S5: After the flood season, the diversion tunnel 1 is discharged and stored water according to the flow of the reservoir. When the reservoir water level reaches the target water level, the diversion tunnel 1 is closed.

[0062] S6: After the gate of diversion tunnel 1 is closed, the B1 plugging body 12 is removed, the permanent plug 3 is constructed, the permanent plug 3 is backfilled and grouted, the joints of the permanent plug 3 are connected and grouted for consolidation, the tunnel is cleaned and facilities are removed, and the diversion tunnel 1 is blocked to add a new traffic tunnel;

[0063] S7: While S6 is being carried out, the No. 1 plugging body 6, the No. 2 plugging body 7 and the B2 plugging body are removed, and the lining surfaces of the plugging sections of the No. 1 plugging body 6 and the No. 2 plugging body 7 are repaired; the plugging body construction of the C plugging body 17 at the end of the non-combined section 8 of the diversion tunnel is completed, the facilities in the tunnel are cleaned and removed, the diversion tunnel branch tunnel 11 is blocked, and the C plugging body 17 is installed, realizing the functional conversion of the permanent structure. Its body design meets the requirements of the emptying tunnel flow, and finally meets the multi-functional requirements of the ultra-high rockfill dam.

[0064] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam, characterized in that: The invention comprises a diversion tunnel (1) and a drain hole (13), wherein the drain hole (13) comprises a drain hole non-combined section (9), a drain hole intersection section (14) and a drain hole combination section (10), wherein the drain hole non-combined section (9), the drain hole intersection section (14) and the drain hole combination section (10) are connected, wherein the diversion tunnel (1) comprises a diversion tunnel inlet discharge control gate chamber (2) and a diversion tunnel non-combined section (8), wherein the diversion tunnel inlet discharge control gate chamber (2) is connected to the diversion tunnel non-combined section (8), wherein the diversion tunnel non-combined section (8) intersects with the drain hole non-combined section (9) at the drain hole intersection section (14) and merges with the drain hole combination section (10) to form a Y shape; The vent hole non-combined section (9) is provided with a vent hole accident lock chamber (4) and a vent hole working lock chamber (5), and along the water flow direction, the vent hole accident lock chamber (4) is arranged in front of the vent hole working lock chamber (5); The non-combined section (8) of the diversion tunnel is provided with a permanent plug (3), and along the water flow direction, the diversion tunnel inlet control sluice chamber (2) is provided in front of the permanent plug (3); Before the main flood season, a No. 1 plugging body (6) and a No. 2 plugging body (7) are arranged at the intersection of the end of the drain hole non-combined section (9) and the diversion hole non-combined section (8), wherein the No. 1 plugging body (6) and the No. 2 plugging body (7) are on the drain hole non-combined section (9), and the No. 2 plugging body (7) is outside the intersection. Along the water flow direction, the No. 1 plugging body (6) is in front of the No. 2 plugging body (7); The non-combined section (8) of the diversion tunnel is provided with a diversion tunnel branch hole (11), and along the water flow direction, the diversion tunnel branch hole (11) is arranged at the rear side of the permanent plug (3); Before the main flood season, a B1 plugging body (12) is provided in the diversion tunnel branch tunnel (11).

2. A combined structure of diversion tunnel and venting tunnel for ultra-high rockfill dam according to claim 1, characterized in that: The vent hole combination section (10) is provided with a vent hole lower branch hole (16), and along the water flow direction, the vent hole lower branch hole (16) is at the front end of the vent hole combination section (10).

3. A combined structure of diversion tunnel and venting tunnel for ultra-high rockfill dam according to claim 2, characterized in that: Before the main flood season, a B2 plugging body (15) is provided in the lower branch tunnel (16) of the drain tunnel.

4. A construction method for a combined structure of a diversion tunnel and a venting tunnel for an ultra-high rockfill dam according to claim 3, characterized in that: The steps include: S1: rock mass excavation, completion of the through-construction of the diversion tunnel (1) and the drain tunnel (13); S2: Complete the lining construction of the diversion tunnel (1) and the venting tunnel (13), and complete the construction of the diversion tunnel inlet discharge control chamber (2), the venting tunnel emergency chamber (4) and the venting tunnel working chamber (5); S3: Before the main flood season, the No. 1 plugging body (6) and the No. 2 plugging body (7) are cast; S4: During the main flood season, the diversion tunnel (1) and the drain tunnel combined section (10) form a main flood season diversion channel to meet the main flood season flow requirements; S5: After the flood season, the diversion tunnel (1) is opened for controlled discharge and water storage according to the flow rate of the reservoir. When the reservoir water level reaches the target water level, the diversion tunnel (1) is closed. S6: After the gate of the diversion tunnel (1) is closed, the B1 plugging body (12) is removed, the permanent plug (3) is constructed, the permanent plug (3) is backfilled and grouted, the joints and consolidation grouting of the permanent plug (3) are performed, the tunnel is cleaned and facilities are removed, the diversion tunnel (1) is sealed, and a new traffic tunnel is added; S7: While S6 is being carried out, the No. 1 plugging body (6), the No. 2 plugging body (7) and the B2 plugging body (15) are removed, and the lining surfaces of the plugging sections of the No. 1 plugging body (6) and the No. 2 plugging body (7) are repaired; the plugging body construction of the C plugging body at the end of the non-combined section (8) of the diversion tunnel is completed, the tunnel is cleaned and the facilities are removed, and the diversion tunnel branch tunnel (11) is blocked.

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