A water tunnel construction adit plugging structure and construction method

Abstract

The application provides a water tunnel construction adit plugging structure and a construction method. The plugging structure comprises a tunnel main body, a construction adit, an air conditioning room, a connecting tunnel and a plugging structure. The construction adit is arranged downstream of the tunnel main body, and the construction adit is divided into upper and lower construction adits and connected to the upper end and the right end of the air conditioning room respectively. The air conditioning room is connected to the tunnel main body through the connecting tunnel. The plugging structure comprises five sections. The application also provides a construction method of the above-mentioned plugging structure, which comprises five steps of surrounding rock pretreatment, main plugging section construction, transition plugging section construction, auxiliary plugging section construction and quality detection. Through multi-section differential plugging design and targeted grouting measures, the application effectively adapts to the periodic pressure fluctuation of the air cushion type surge chamber, improves the compactness, impermeability and overall stability of the plugging body, the construction parameters are clear, the quality is controllable, and the application is suitable for the water tunnel construction adit plugging scene of water conservancy projects, and has good engineering applicability and economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy engineering technology, specifically relating to a sealing structure and construction method for a construction adit of a hydraulic tunnel. Background Technology

[0002] In water conservancy projects, hydraulic tunnels, as core water conveyance or diversion structures, often require the construction of adits during construction to achieve "shorter tunnel construction" and accelerate the construction progress while reducing excavation difficulty. Among these, the construction adits associated with air-cushion surge chambers, due to the periodic pressure fluctuations (typically within the range of 0.2~0.8MPa) during surge chamber operation, place far higher demands on the sealing, pressure resistance, and fatigue resistance of the adit sealing structure than conventional adits. The rational design and construction quality of the sealing structure directly affect the safety and construction efficiency of the project. However, existing hydraulic tunnel construction adit sealing technologies, when adapted to the conditions of air-cushion surge chambers, suffer from the following technical challenges, making it difficult to meet the requirements for project safety and long-term stable operation.

[0003] (1) Existing sealing structures have poor adaptability and cannot match the pressure characteristics of air cushion type surge chambers. Conventional construction tunnel sealing often uses a single concrete plug (such as the sealing structure of a diversion tunnel intersecting a water diversion tunnel disclosed in CN114045799B), which only considers the static sealing effect and does not design for the dynamic pressure fluctuations of air cushion type surge chambers. When the pressure in the surge chamber increases, the contact surface between the sealing body and the surrounding rock is prone to gaps due to uneven stress; when the pressure decreases, negative pressure is easily formed inside the sealing body, causing air to seep in. Under long-term repeated action, the sealing body is prone to cracking and leakage, and in severe cases, it is necessary to shut down for maintenance, affecting the normal operation of the project.

[0004] (2) Insufficient compactness of the sealing body makes it difficult to guarantee seepage prevention performance. Existing sealing technologies mostly rely on single concrete pouring or simple grouting, without precise design based on the surrounding rock characteristics and construction parameters of the air cushion type pressure regulating chamber tunnel. On the one hand, during the concrete pouring process, honeycomb and pitting are easily generated due to poor formwork splicing and insufficient vibration, especially at the arch top of the tunnel, where voids are easily formed due to insufficient self-compacting of the concrete; on the other hand, the grouting system is arranged in a chaotic manner, and the grouting pressure and grout ratio are not targeted, resulting in uneven grouting range, and some areas are not effectively filled, leaving leakage channels at the interface between the sealing body and the surrounding rock.

[0005] (3) The construction process parameters are vague and the quality stability is poor. The existing sealing construction schemes mostly rely on experience parameters and do not formulate differentiated construction parameters for the specific working conditions of the air cushion pressure regulating chamber tunnel (such as the surrounding rock type, tunnel diameter, and pressure level).

[0006] In summary, existing hydraulic tunnel construction adit sealing technologies have problems such as poor adaptability, insufficient density, weak crack resistance, and unclear construction parameters when adapted to the working conditions of air cushion type pressure chambers. Summary of the Invention

[0007] The purpose of this invention is to provide a sealing structure and construction method for the adit of a hydraulic tunnel, which is suitable for the pressure characteristics of an air cushion pressure regulating chamber, ensures the sealing density and structural stability, and has clear construction parameters, so as to meet the requirements of safe operation of the project.

[0008] To achieve the above-mentioned technical features, the present invention aims to provide a sealing structure for a construction adit of a hydraulic tunnel, comprising a tunnel body, a construction adit, a controlled atmosphere chamber, a connecting tunnel, and a sealing structure. The construction adit is located downstream of the tunnel body and is excavated upstream to form an upper construction adit and a lower construction adit, which are respectively connected to the upper and right ends of the controlled atmosphere chamber. The controlled atmosphere chamber is connected to the tunnel body via the connecting tunnel. The sealing structure is located at the construction adit and consists of five sections. The main sealing section is located at the AA section of the upper construction adit and the BB section of the lower construction adit. The transition sealing section is located at the CC section, and the auxiliary sealing sections are located at the DD and EE sections. These five sections together form the overall sealing structure of the construction adit.

[0009] Preferably, the main cross-section of the tunnel is circular, constructed using a TBM, and the slope is 2.0~3.0%. The support parameters for the main tunnel are as follows: anchor bolt diameter 12~20mm, length 2.5~3.0m, row spacing 0.8~1.2m, wire mesh and sprayed concrete 15~20cm thick, full ring steel arch frame HEB120, spacing 0.8~1.2m, protective layer thickness 5~7cm, drainage holes with PVC perforated pipes of 50~70mm diameter inserted, wrapped with geotextile, penetrating 20~30cm into the rock, row spacing 1.8~2.5m.

[0010] Preferably, the cross-sectional shape of the construction adit is that of a city gate, with an excavation width of 6.0~6.5m, a height of 6.0~6.3m, an arch height of 2.0~2.3m, and an overall slope of 7.0~8.0%, wherein the slope of the upper construction adit is 7.5~8.0%, and the slope of the lower construction adit is -2.85~-3.25%.

[0011] Preferably, the upper part of the controlled atmosphere chamber is connected to the upper construction adit, the right side is connected to the lower construction adit, and the lower part is connected to the main tunnel through a connecting tunnel.

[0012] Preferably, the sealing structure is divided into 5 sections for sealing, with sections AA and BB being the main sealing sections. The sealing construction parameters for section AA are as follows: full-section C25 concrete plug, backfill grouting within the 80~100° range of the top arch, row spacing of 1.8~2.2m, extending 0.3~0.4m into the bedrock, with 3 / 4 holes staggered in each row, φ25 anchor rods, length 3.0~3.5m, 7 / 8 rods arranged, row spacing of 2.8~3.4m, for a total of two rows; the sealing construction parameters for section BB are the same as those for section AA, except that two rows of PVC connecting pipes with a diameter of 180~220mm are added at the bottom, with a horizontal spacing of 100~120cm and a vertical spacing of 35~45cm.

[0013] Preferably, the CC section is a transition sealing section, and the sealing construction parameters are as follows: 0.65~0.75m thick C25 reinforced concrete lining, backfill grouting within the range of 110~130° of the top arch, row spacing of 1.8~2.2m, extending into the bedrock of 0.2~0.4m, with 3 / 4 holes staggered in each row, and consolidation grouting of the left and right sidewalls and bottom, row spacing of 1.8~2.2m, staggered in each row, extending into the bedrock of 2.8~3.2m.

[0014] Preferably, the sealing construction parameters for the five sections of the sealing structure are as follows: 0.65~0.75m thick C25 reinforced concrete lining, backfill grouting within the range of 110~130° of the top arch, row spacing of 1.8~2.2m, extending into the bedrock of 0.2~0.4m, with 3 / 4 holes staggered in each row, and consolidation grouting of the left and right sidewalls and bottom, row spacing of 1.8~2.2m, staggered in each row, extending into the bedrock of 2.8~3.2m.

[0015] Preferably, another aspect of the present invention provides a sealing structure and construction method for a hydraulic tunnel construction adit, comprising the following steps: S1, surrounding rock pretreatment, cleaning the floating slag and loose rock blocks on the surface of the surrounding rock at each sealing section of the construction adit to ensure the safety of the sealing construction; S2, the main sealing section construction, can be carried out simultaneously or sequentially on the AA and BB sealing sections. After pouring concrete, it should be covered and kept moist for curing, and the curing time should not be less than 7 days. S3, Transition sealing section construction: After the main sealing section is completed and cured, CC sealing section construction is carried out. After pouring concrete, it is covered and moisturized for curing. The curing time is not less than 7 days. S4, after the construction and maintenance of the auxiliary sealing section and the transition sealing section are completed, the DD and EE sealing sections are constructed in sequence. After the concrete is poured, it is covered and kept moist for curing. The curing time is not less than 7 days. S5. Quality inspection: The density of the sealing body is tested using an ultrasonic detector, and the density is required to be no less than 97%. The seepage prevention effect is tested through a water seepage test, and the seepage rate is no more than 0.02L / (m・d). A pressure test is conducted by simulating the pressure change of an air cushion pressure regulating chamber. If there are no cracks or leaks in the sealing body, the sealing construction is completed.

[0016] The pressure variation in the simulated air cushion pressure regulating chamber is between 0.2 and 0.8 MPa.

[0017] The present invention has the following beneficial effects: 1. The technical solution described in this invention seals the construction tunnel by setting up a main sealing section, a transition sealing section and an auxiliary sealing section, which can better adapt to the pressure fluctuations of the air cushion type pressure regulation, achieve a smooth transition of the sealing section, and effectively improve the stability of the sealing structure.

[0018] 2. The technical solution described in this invention performs top arch backfill grouting and perimeter consolidation grouting construction according to different types of sealing sections, which can fill the tiny gaps between the sealing body and the surrounding rock, improve the compactness of the sealing structure in sections, and meet the sealing requirements of the air cushion pressure regulating chamber for long-term operation.

[0019] 3. The sealing method described in this invention is implemented in stages, with smooth connections between each process. No special equipment is required. The construction parameters for different types of sealing sections are clearly defined, ensuring that the quality of each sealing process is controllable. This can reduce later operation and maintenance costs and significantly improve the economic and social benefits of the project. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a plan view of the sealing structure of the present invention; Figure 2 This is a schematic diagram of the AA sealing cross-section of the present invention; Figure 3 This is a schematic diagram of the BB sealing cross-section of the present invention; Figure 4 This is a schematic diagram of the CC blocking cross-section of the present invention; Figure 5 This is a schematic diagram of the DD sealing cross-section of the present invention; Figure 6 This is a schematic diagram of the EE sealing cross-section of the present invention.

[0022] In the diagram: 1-Main tunnel, 2-Construction adit, 21-Upper construction adit, 22-Lower construction adit, 3-Controlled atmosphere chamber, 4-Connecting tunnel, 5-Sealing structure, 51-AA type sealing, 52-BB type sealing, 53-CC type sealing, 54-DD type sealing, 55-EE type sealing, 6-C25 concrete, 7-Anchor bolt, 8-Grouting for backfilling the arch, 9-Grouting for consolidation around the perimeter. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Reference Figures 1 to 6 This invention discloses a sealing structure and construction method for a construction adit of a hydraulic tunnel, comprising a tunnel body 1, a construction adit 2, a controlled atmosphere chamber 3, a connecting tunnel 4, and a sealing structure 5. The construction adit 2 is located downstream of the tunnel body 1. The construction adit 2 is excavated upstream to form an upper construction adit 21 and a lower construction adit 22, which are respectively connected to the upper and right ends of the controlled atmosphere chamber 3. The controlled atmosphere chamber 3 is connected to the tunnel body 1 through the connecting tunnel 4. The sealing structure 5 is located at the construction adit 2 and consists of 5 sections. The main sealing section is located at the AA section of the upper construction adit and the BB section of the lower construction adit. The transition sealing section is located at the CC section. The auxiliary sealing sections are located at the DD and EE sections. The 5 sections together form the overall sealing structure of the construction adit 2.

[0025] As an optional implementation method, the main tunnel section 1 is circular and constructed using a full-face tunnel boring machine (TBM). This construction method can ensure the accuracy and efficiency of tunnel excavation, and avoid excessive disturbance to the surrounding rock caused by conventional excavation methods. The design slope is 2.0~3.0%. This slope setting needs to be combined with the water conveyance requirements of the project and the terrain conditions to ensure smooth water flow and avoid local water accumulation. The support parameters are as follows: Anchor bolt support: 12 grade III Φ25 anchor bolts, each 3m long, spaced 1.2m apart, arranged in a quincunx pattern, effectively enhancing the integrity of the surrounding rock and preventing loosening and detachment; Shotcrete support: After installing a steel mesh, 15cm thick C25 concrete is sprayed. The steel mesh uses Φ8@200×200mm specifications. The shotcrete can promptly seal the surface of the surrounding rock, reducing weathering; Steel arch support: HEB120 type steel arch frames are installed around the entire ring, spaced 1.2m apart, with a 5cm protective layer. Through the synergistic effect of the steel arch frames, anchor bolts, and shotcrete, a composite support system is formed, improving the tunnel's resistance to deformation; Drainage system: 50mm diameter PVC perforated pipes are inserted into the drainage holes, wrapped with permeable geotextile (200g / m2) to prevent silt blockage. The perforated pipes penetrate 20cm into the rock, and the drainage holes are spaced 2m apart, effectively draining seepage water from the surrounding rock and reducing water pressure. As an optional implementation method, construction adit 2 serves as an auxiliary passage during the construction of the main tunnel 1. After construction, it needs to be sealed. Its parameter design must take into account both construction convenience and sealing safety: the cross-section adopts a city gate shape, which can balance the construction space requirements and structural stability, and avoid the stress concentration problem at the corners of the rectangular cross-section; the excavation width is 6.2m, the height is 6.1m, the arch height is 2.3m, and the arch radius is designed according to the standard of city gate shape to ensure uniform stress on the arch; the overall slope is 7.78%, of which the upper construction adit 21 has a slope of 7.596%, and the lower construction adit 22 has a slope of -3.25% (negative slope indicates downhill). The slope setting needs to be combined with the material transportation and personnel passage requirements during construction, while ensuring the fluidity and compactness of the concrete pouring during sealing.

[0026] As an optional implementation, the air cushion pressure regulating chamber functions to balance pressure fluctuations during tunnel operation. The upper part is connected to the upper construction adit 21, the right side is connected to the lower construction adit 22, and the lower part is connected to the tunnel body 1 through the connecting tunnel 4, forming an "upper-right-lower" three-dimensional connection system, ensuring that pressure fluctuations can be buffered by the air regulating chamber 3 and then transmitted to the tunnel body 1.

[0027] Reference Figure 2 and Figure 3 As an optional implementation method, the sealing structure 5 is divided into 5 sections for sealing. Through the phased sealing of the 5 sections, a three-level sealing system of "main-transition-auxiliary" is formed. The parameters of each section are designed specifically to adapt to the stress and seepage prevention requirements of different locations. Among them, sections AA and BB are the main sealing sections. The sealing construction parameters of section AA are: full-section C25 concrete plug, backfilling and grouting within the 90° range of the top arch, row spacing of 2m, extending into the bedrock of 0.3m, with 3 / 4 holes staggered in each row, φ25 anchor rods, 3m in length, 7 / 8 rods arranged, row spacing of 3m, for a total of two rows; the sealing construction parameters of section BB are the same as those of section AA, except that two rows of 200mm diameter PVC connecting pipes are added at the bottom, with a horizontal spacing of 113cm and a vertical spacing of 40cm.

[0028] Reference Figure 4 As an optional implementation method, the sealing structure 5 is divided into 5 sections for sealing, among which the CC section is a transition sealing section. The sealing construction parameters are: 0.7m thick C25 reinforced concrete lining, backfilling and grouting within a 120° range of the top arch, row spacing of 2m, extending into the bedrock of 0.3m, with 3 / 4 holes staggered in each row, and consolidation grouting of the left and right sidewalls and bottom, row spacing of 2m, staggered in each row, extending into the bedrock of 3m.

[0029] Reference Figure 5 and Figure 6As an optional implementation method, the sealing structure 5 is divided into 5 sections for sealing. Among them, sections DD and EE are auxiliary sealing sections. The sealing construction parameters for section DD are: full-section C25 concrete plug, backfill grouting within the 90° range of the top arch, row spacing of 2m, extending 0.3m into the bedrock, with 3 / 4 holes staggered in each row; peripheral consolidation grouting, row spacing of 2m, staggered in each row, extending 3m into the bedrock; φ25 anchor bolts, 3m in length, arranged in 7 / 8 positions, row spacing of 3m. The sealing parameters for section EE are: hollow peripheral C25 reinforced concrete plug, the cavity cross section is arch-shaped, 2.5m wide and 2.4m high, and the other parameters are the same as those for section DD.

[0030] Reference Figures 1 to 6 A construction method for a sealing structure for a hydraulic tunnel construction adit, using the aforementioned sealing structure for a hydraulic tunnel construction adit, includes the following steps: Step 1: Surrounding rock pretreatment. Using a combination of manual labor and machinery (small excavators, pneumatic drills), the surface of the surrounding rock at each sealing section (AA, BB, CC, DD, EE) of the construction adit 2 is cleared of loose debris, loose rock fragments, and contaminants within fissures. For surrounding rock with obvious fissures, epoxy mortar is used for surface sealing to prevent fissure expansion during subsequent construction. Quality requirements: The surface flatness error of the surrounding rock should not exceed 5cm, there should be no loose rock fragments larger than 10cm in diameter, and the fissure sealing rate should reach 100%, ensuring the safety of subsequent sealing construction and the quality of concrete pouring.

[0031] Step 2: Construction of the main sealing section. Sections AA and BB can be constructed simultaneously or sequentially depending on site conditions. When constructing simultaneously, separate pouring templates and grouting systems must be set up to avoid mutual interference. Pumped concrete should be used for pouring, with the pouring speed controlled within 2m / h, and the layer thickness 30~50cm. Each layer should be vibrated to ensure compaction, and the distance between vibrator movements should not exceed 40cm to avoid under-vibration or over-vibration. When pouring section BB, the PVC connecting pipe must be accurately positioned and fixed with steel reinforcement frames to ensure that the pipe position deviation does not exceed 10mm. After the concrete is poured, cover it with geotextile and sprinkle water for moisturizing and curing within 12 hours. The curing time should not be less than 7 days, and the temperature difference between the concrete surface and the ambient temperature should not exceed 25℃ during the curing period to prevent temperature cracks.

[0032] Step 3: Construction of the transition sealing section. The CC section can only be constructed after the concrete strength of the main sealing section reaches 70% of the design strength (as tested by test blocks cured under the same conditions). The concrete pouring and curing requirements are the same as those for the main sealing section, and the curing time shall not be less than 7 days.

[0033] Step 4: Construction of the auxiliary plugging section. First, construct the D-D section. After the concrete strength of the D-D section reaches 70% of the design strength, then construct the E-E section. A customized steel formwork is used to form a horseshoe-shaped cavity. The steel formwork should have sufficient stiffness to prevent deformation during concrete pouring. The inner wall formwork of the cavity can be removed after the concrete strength reaches 80% of the design strength. After removal, the inner wall of the cavity should be plastered in time. The concrete pouring, grouting, anchor rod construction, and maintenance of the D-D and E-E sections shall be carried out in accordance with the requirements of the main plugging section and the transition plugging section.

[0034] Step 5: Quality inspection. An ultrasonic detector is used to conduct a full-section inspection on each plugging body. The distance between inspection points shall not be greater than 1 m. It is required that the compactness of the plugging body is not less than 97%. For the areas with insufficient compactness (less than 97%) found during inspection, drilling and grouting (cement slurry with a water-cement ratio of 0.5:1) shall be used for reinforcement. Water seepage tests are carried out through drilling. The distance between test holes is 5 m, and the test pressure is 0.3 MPa. It is required that the seepage rate is not greater than 0.02 L / (m·d). For the areas where the seepage rate exceeds the standard, grouting holes shall be densified for anti-seepage treatment. Simulate the pressure change (0.2 - 0.8 MPa) of the air-cushioned surge chamber and conduct a pressure cycle test in 5 levels (0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa, 0.6 MPa, 0.4 MPa, 0.2 MPa). The pressure is maintained for 30 min at each level. If there are no cracks or leakage on the surface of the plugging body and the pressure does not drop significantly (the pressure drop is not greater than 0.05 MPa), it is considered qualified. After all the above three inspections are qualified, the plugging construction is completed and the project can be delivered for use.

[0035] The above shows the basic process of the present invention, the basic principles utilized, and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. Any replacements or changes that can be easily conceived without departing from the spirit and scope of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A sealing structure for a construction adit of a hydraulic tunnel, characterized in that, The tunnel includes a main tunnel (1), a construction adit (2), a controlled atmosphere chamber (3), a connecting tunnel (4), and a sealing structure (5). The construction adit (2) is set downstream of the main tunnel (1). The construction adit (2) is excavated upstream to form an upper construction adit (21) and a lower construction adit (22), which are respectively connected to the upper end and the right end of the controlled atmosphere chamber (3). The controlled atmosphere chamber (3) is connected to the main tunnel (1) through the connecting tunnel (4). The sealing structure (5) is set at the construction adit (2) and is divided into 5 sections. The main sealing section is set at the AA section of the upper construction adit and the BB section of the lower construction adit. The transition sealing section is set at the CC section. The auxiliary sealing sections are set at the DD and EE sections. The 5 sections together form the overall sealing structure of the construction adit (2). The AA section is located at the entrance of the upper construction adit (21) connecting to the controlled atmosphere chamber (3); the BB section is located at the entrance of the lower construction adit (22) connecting to the controlled atmosphere chamber (3); the CC section is located in the section of the construction adit (2) before it bifurcates, and is located downstream of the AA and BB sections; the DD section is located downstream of the CC section along the construction adit (2) from upstream to downstream; the EE section is located downstream of the DD section along the construction adit (2) from upstream to downstream.

2. The sealing structure for a hydraulic tunnel construction adit according to claim 1, characterized in that, The main body of the tunnel (1) has a circular cross-section, is constructed using a TBM, and has a slope of 2.0~3.0%; The support parameters for the main body of the tunnel (1) are as follows: anchor bolt diameter 12~20mm, length 2.5~3.0m, row spacing 0.8~1.2m, netting and spraying 15~20cm thick concrete, full ring steel arch frame HEB120, spacing 0.8~1.2m, protective layer thickness 5~7cm, drainage hole with 50~70mm diameter PVC flower pipe, wrapped with geotextile, penetrating 20~30cm into the rock, row spacing 1.8~2.5m.

3. The sealing structure for a hydraulic tunnel construction adit according to claim 1, characterized in that, The construction adit (2) has a cross-sectional shape resembling a city gate, with an excavation width of 6.0~6.5m, a height of 6.0~6.3m, an arch height of 2.0~2.3m, and an overall slope of 7.0~8.0%. The upper construction adit (21) has a slope of 7.5~8.0%, and the lower construction adit (22) has a slope of -2.85~-3.25%.

4. The sealing structure for a hydraulic tunnel construction adit according to claim 1, characterized in that, The upper part of the controlled atmosphere chamber (3) is connected to the upper construction adit (21), the right side is connected to the lower construction adit (22), and the lower part is connected to the main body of the tunnel (1) through the connecting tunnel (4).

5. The sealing structure for a hydraulic tunnel construction adit according to claim 1, characterized in that, The sealing structure (5) is divided into 5 sections for sealing, of which sections AA and BB are the main sealing sections. The sealing construction parameters for section AA are: full-section C25 concrete plug, backfill grouting within the range of 80~100° of the top arch, row spacing of 1.8~2.2m, extending into the bedrock of 0.3~0.4m, with 3 / 4 holes staggered in each row, φ25 anchor rods, length of 3.0~3.5m, 7 / 8 rods arranged, row spacing of 2.8~3.4m, for a total of two rows; the sealing construction parameters for section BB are the same as those for section AA, except that two rows of PVC connecting pipes with a diameter of 180~220mm are added at the bottom, with a horizontal spacing of 100~120cm and a longitudinal spacing of 35~45cm.

6. The sealing structure for a hydraulic tunnel construction adit according to claim 5, characterized in that, The CC section is a transitional sealing section. The sealing construction parameters are as follows: 0.65~0.75m thick C25 reinforced concrete lining; backfilling and grouting within the range of 110~130° of the top arch; row spacing of 1.8~2.2m; extending into the bedrock 0.2~0.4m; 3 / 4 holes per row are staggered; consolidation grouting of the left and right sidewalls and bottom; row spacing of 1.8~2.2m; staggered arrangement of each row; extending into the bedrock 2.8~3.2m.

7. The sealing structure for a hydraulic tunnel construction adit according to claim 6, characterized in that, The sealing construction parameters for the DD and EE sections of the sealing structure (5) are as follows: 0.65~0.75m thick C25 reinforced concrete lining, grouting within the 110~130° range of the top arch, row spacing of 1.8~2.2m, extending into the bedrock of 0.2~0.4m, with 3 / 4 holes staggered in each row, and grouting for consolidation between the left and right sidewalls and the bottom, row spacing of 1.8~2.2m, staggered in each row, extending into the bedrock of 2.8~3.2m.

8. A construction method for a sealing structure for a hydraulic tunnel construction adit as described in claim 7, characterized in that, Includes the following steps: S1, surrounding rock pretreatment, cleaning the floating slag and loose rock blocks on the surface of the surrounding rock at each sealing section of the construction adit to ensure the safety of the sealing construction; S2, the main sealing section construction, can be carried out simultaneously or sequentially on the AA and BB sealing sections. After pouring concrete, it should be covered and kept moist for curing, and the curing time should not be less than 7 days. S3, Transition sealing section construction: After the main sealing section is completed and cured, CC sealing section construction is carried out. After pouring concrete, it is covered and moisturized for curing. The curing time is not less than 7 days. S4, after the construction and maintenance of the auxiliary sealing section and the transition sealing section are completed, the DD and EE sealing sections are constructed in sequence. After the concrete is poured, it is covered and kept moist for curing. The curing time is not less than 7 days. S5. Quality Inspection: The density of the sealing body is tested using an ultrasonic tester, requiring a density of not less than 97%. The seepage prevention effect is tested through a water seepage test, with a seepage rate not exceeding 0.02 L / (m³). d) Conduct a pressure test simulating pressure changes in the pressure regulating chamber, and observe that the sealing body shows no cracks or leakage. The sealing construction is then complete.

9. The construction method of the sealing structure for a hydraulic tunnel construction adit according to claim 8, characterized in that, The simulated pressure regulation chamber pressure variation is between 0.2 and 0.8 MPa.

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