A method for plugging concentrated water inrush channels in underground engineering

Abstract

The present invention discloses a method for plugging concentrated water inrush channels in underground engineering. The present invention creates a water plugging construction working surface by pouring a flat pressure plug at the water inrush site to balance the groundwater pressure and control the groundwater from flowing into the underground chamber. The water pressure and flow rate of the groundwater channel are controlled and observed through drainage and pressure relief boreholes at the upstream and downstream of the concentrated groundwater channel and at the heading face. A "cofferdam" of the water conduction channel is formed by "grating + formwork bag grouting" through directional boreholes at the upstream and downstream of the concentrated groundwater channel. The upstream cofferdam blocks the groundwater flow in the groundwater channel, converting the groundwater channel into a waterless or static state; the downstream cofferdam blocks the backfill materials such as concrete to prevent the leakage of the backfill materials. The groundwater channel within the cofferdam is filled densely by injecting backfill materials such as concrete through the directional boreholes. Systematic grouting is carried out on the plugging body, the cofferdam and the surrounding rock of the underground space to completely plug the groundwater and form a surrounding rock consolidation ring, so that the excavation of the underground chamber can continue to advance.

Description

Technical Field

[0001] The present invention relates to a structure for blocking water inrush channels, and in particular to a structure for blocking concentrated water inrush channels in underground engineering. Background Art

[0002] The concentrated water inrush in underground engineering is extremely destructive and often causes heavy casualties and property losses. At present, the treatment measures for concentrated water inrush channels in underground engineering are generally divided into "drainage, avoidance, and blocking". "Drainage" means discharging groundwater from the underground engineering by pumping or gravity flow, and then constructing after the water inrush volume decreases or is completely drained. This often captures the original underground runoff and changes the groundwater seepage field, which can directly lead to a drop in the regional groundwater level, causing surface well water to dry up, spring water to stop flowing, river water to infiltrate, crop production to decrease, surface plants to wither and die, etc., thus directly or indirectly affecting the production and life of local residents, and even causing environmental geological problems such as ground settlement and surface collapse. "Avoidance" means changing the location of the underground engineering, such as changing the tunnel alignment, etc. The result is often a significant increase in investment and construction period. "Blocking" refers to using engineering measures to block the water inrush channels within the tunnel range, allowing groundwater to flow around the tunnel, which can effectively protect underground water resources and have the least impact on the groundwater environment, meeting the concept of green ecology.

[0003] However, the concentrated water inrush in underground engineering generally has the characteristics of "hidden burial", "high pressure", and "large flow rate". Under the action of high-pressure and large-flow water inrush, the blocking materials are often washed away continuously, resulting in material waste and it is difficult to achieve the blocking effect. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for blocking concentrated water inrush channels in underground engineering. This structure can systematically solve the problem of concentrated water inrush from karst underground rivers, pipelines, or fault open fractures and broken zones within a relatively short range (less than 50 m) in front of the surrounding rock or the heading face during the excavation of underground engineering, tunnels, and tunnels.

[0005] The technical solution of the present invention: A method for blocking concentrated water inrush channels in underground engineering includes the following steps:

[0006] S1. When the underground engineering is excavated to the heading face, it is necessary to detect in advance whether there is a water-conducting space in front of the heading face. If it exists, its scale and the direction of underground water flow should be determined. When the exposure of the heading face will cause water inrush in the water-conducting space or its branch channels, stop the excavation.

[0007] S2. Set diversion holes: Open holes in the chamber behind the heading face, and drill holes towards the direction of the underground water flow source outside the underground chamber to the water-conducting space, that is, the first diversion hole; open holes in the chamber behind the heading face, and drill holes towards the direction of the underground water flow discharge outside the underground chamber to the water-conducting space, that is, the second diversion hole.

[0008] S3. Install the diversion pipe on the face to divert and relieve the water gushing from the face;

[0009] S4. Cast a flat pressure plug behind the face to block the underground water that was exposed earlier;

[0010] S5. Set up steel gratings in the water direction of the water diversion space: open a hole on the flat pressure plug, and directional drill holes in the direction of the groundwater source between the inner side of the first diversion hole and the outer side of the underground cavern. The holes pass through the water diversion space and reach the intact bedrock in front of the water diversion space. Insert steel pipes through the holes. The number of steel pipes is determined according to the size of the holes in the water diversion space, and a row of steel gratings A is formed in the direction of the groundwater source of the water diversion space;

[0011] S6. Grouting of mold bag in the water-conducting space in the direction of water inflow: a hole is opened on the outer side of the steel grid A of the flat pressure plug, and a drill hole A is set in parallel with the steel grid A. The drill hole A is connected to the water-conducting space, and a mold bag A is placed in the water-conducting space along the drill hole A. Grouting is injected into the mold bag A. The mold bag grouting is repeated until the water volume and water pressure in the second diversion hole are reduced;

[0012] S7. Set up steel gratings in the drainage direction of the water diversion space: open a hole in the flat pressure plug, and directional drill holes in the drainage direction of the groundwater flow between the inner side of the second diversion hole and the outer side of the underground cavern. The holes are drilled through the water diversion space to the intact bedrock in front of the water diversion space. Steel pipes are inserted through the holes. The number of steel pipes is determined according to the size of the holes in the water diversion space, and a row of steel gratings B is formed in the drainage direction of the groundwater in the water diversion space;

[0013] S8. Mould bag grouting in the drainage direction of the water diversion space: a hole is opened inside the steel grid B of the flat pressure plug, a drill hole B is set parallel to the steel grid B, the drill hole B is connected to the water diversion space, a mould bag B is placed in the water diversion space along the drill hole B, grouting is injected into the mould bag B, and the mould bag grouting is repeated until the water volume and water pressure in the second diversion hole are greatly reduced;

[0014] S9. Pouring filling materials to fill the main holes of the water-conducting space: the flat-pressure plug is divided into three areas, and the three areas are respectively provided with borehole C, borehole D, and borehole E. There are multiple boreholes C, borehole D, and borehole E arranged from low to high. First, the filling material is pressed into the borehole C to fill the water-conducting space, and the filling material is gradually piled up. When the borehole D returns to the slurry, the borehole C is closed, and the filling material is pressed into the borehole D to fill the water-conducting space. The filling material is gradually piled up. When the borehole E returns to the slurry, the borehole D is closed, and the filling material is pressed into the borehole E to fill the water-conducting space. The filling material is gradually piled up. This step is repeated until the main holes of the water-conducting space are densely filled;

[0015] S10. System grouting in front of the heading face and surrounding rock system of underground engineering: Radially arrange grouting holes in front of the pressure equalizing plug, and conduct system grouting on the rock mass in front of the heading face and the surrounding rock in front of the cavern to completely block the water conduction channels and form a stable consolidation circle for the surrounding rock of the underground cavern;

[0016] S11. Close the first diversion hole, and excavate the underground cavern through the water gushing area.

[0017] In the method for blocking concentrated water conduction channels in underground engineering described above, valves are provided on the first diversion hole and the second diversion hole on the side of the underground cavern to adjust the flow rate of diversion as needed.

[0018] In the method for blocking concentrated water conduction channels in underground engineering described above, after S6, if the structure of 1 row of steel grids + formwork bags formed by S5 and S6 has a poor water control effect on the water coming from the upstream direction, then the number of rows of steel grid A and formwork bag A can be increased adjacent to the upstream of the completed formwork bag.

[0019] In the method for blocking concentrated water conduction channels in underground engineering described above, during the installation of the steel grid, the spacing between adjacent steel pipes is 0.3 - 0.5 m.

[0020] In the method for blocking concentrated water conduction channels in underground engineering described above, in S1, when the underground engineering is excavated to the heading face, it is necessary to detect in advance whether there is a water conduction space within 50 m in front of the heading face. If there is, then proceed with the subsequent steps. If there is no water conduction space or the water conduction space exists beyond 50 m, then directly conduct normal excavation.

[0021] In the method for blocking concentrated water conduction channels in underground engineering described above, in S3, a valve is installed on the diversion pipe during its installation. During S4, after the strength of the pressure equalizing plug meets the anti - water pressure requirements, the valve of the diversion pipe can be closed during the plugging construction to provide a water - free working surface for the plugging construction.

[0022] In the method for blocking concentrated water conduction channels in underground engineering described above, when the width of the water conduction space > 0.5 m, construct according to the steps of S1 - S11; when the width of the water conduction space ≤ 0.5 m, remove steps S5 and S7 in S1 - S11 and then construct.

[0023] Advantages of the present invention: Compared with the prior art, the object of the present invention is to systematically solve the problem of concentrated water inrush from karst underground rivers, pipelines, or fault open fractures and fractured zones within a relatively short range (distance less than 50 m) in front of the surrounding rock or the heading face during the excavation of underground projects, tunnels, and tunnels. When underground spaces such as underground projects, tunnels, and tunnels are located below the groundwater level, water inrush is directly revealed during the excavation of the underground project, or advanced geological forecasting reveals the existence of a concentrated groundwater channel in front of the surrounding rock and the heading face. The groundwater channel often has the same or similar elevation as the excavated underground space. It is inevitable that the underground project excavation needs to pass through this concentrated groundwater channel. The groundwater pressure in the channel is high and the flow rate is large, which severely restricts the construction and operation safety of the underground project. It is necessary to first block the concentrated groundwater channel involved in the underground space to form a reliable water-blocking consolidation circle outside the surrounding rock boundary of the underground space to ensure the safe excavation passage and long-term stable operation of the underground space. For the blocking of the concentrated water inrush channel in the above-mentioned underground space, which is located below the groundwater level, reliable measures need to be taken to control the flow rate and pressure of the water flow on the water-blocking working face to prevent sudden water inrush and ensure construction safety; the working face is located on the heading face of the already excavated underground space, with a narrow space and the concentrated channel cannot be entered, so drilling and minimally invasive blocking are adopted; since the groundwater channel is close to the elevation of the working face, a horizontal or inclined directional drilling scheme needs to be adopted to control the drilling direction.

[0024] By pouring a pressure-balancing plug at the water inrush site to balance the groundwater pressure and control the groundwater from flowing into the underground chamber, a water-blocking construction working face is created. By means of diversion and pressure-relief drilling holes upstream, downstream, and at the heading face of the concentrated groundwater channel, the water pressure and flow rate of the groundwater channel are controlled and observed. By forming a "cofferdam" of the water-conducting channel through directional drilling of "steel grid + grouting bag" upstream and downstream of the concentrated groundwater channel, the upstream cofferdam blocks the groundwater flow in the groundwater channel, converting the groundwater channel into a waterless or static state; the downstream cofferdam blocks backfill materials such as concrete to prevent the leakage of backfill materials. By injecting backfill materials such as concrete through directional drilling, the groundwater channel within the cofferdam is filled densely. The plugging body, cofferdam, and surrounding rock of the underground space are systematically grouted to completely block the groundwater and form a surrounding rock consolidation circle, enabling the excavation of the underground chamber to continue.

[0025] Generally speaking, the present invention mainly forms a reliable water-blocking consolidation circle outside the surrounding rock boundary of the underground space through the mutual cooperation of structures such as pressure-balancing plugs, pressure-relief pipes, diversion and pressure-relief holes, drilling holes, steel pipe grids, grouting bags, filling materials, and systematic grouting, ensuring the safe excavation passage and long-term stable operation of the underground space. At the same time, it can effectively protect underground water resources and reduce the impact on the groundwater environment. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of the present invention after the grouting bag is set up;

[0027] Figure 2Schematic diagram of the structure after drilling at the flat pressing plug for the present invention;

[0028] Figure 3 Schematic diagram of the structure of the present invention;

[0029] Figure 4 Top view layout diagram of the steel grating of the present invention;

[0030] Figure 5 Schematic diagram of the bag grouting of the present invention;

[0031] Figure 6 is Figure 3 The sectional view of A - A' of

[0032] Reference numerals: 1 - underground project, 2 - surrounding rock, 3 - water - conducting space, 4 - underground water flow direction, 5 - branch channel, 6 - heading face, 7 - diversion pipe, 8 - flat pressing plug, 9 - first diversion hole, 10 - second diversion hole, 11 - steel grating A, 12 - drilling hole A, 13 - bag A, 14 - steel grating B, 15 - drilling hole B, 16 - bag B, 17 - drilling hole C, 18 - drilling hole D, 19 - drilling hole E, 20 - grouting hole, 21 - consolidation ring. Detailed implementation manners

[0033] The present invention will be further described below in conjunction with the drawings and embodiments, but it shall not be used as the basis for limiting the present invention.

[0034] Embodiment of the present invention: A method for plugging concentrated water - inrush channels in underground projects, as Figures 1-6 shown, specifically includes the following steps:

[0035] S1. When the underground project 1 is excavated to the heading face 6, it is necessary to detect in advance whether there is a water - conducting space 3 such as a karst underground river pipeline or a tectonic open fracture in front of the heading face 6. If it exists, the size and scale of the water - conducting space 3 and the underground water flow direction 4 should be determined. If the direct exposure of the heading face 6 will cause water inrush in the water - conducting space 3 or its branch channel 5.

[0036] S2. If there is a water - conducting space 3, diversion holes are set. Open holes in the chamber behind the heading face 6, and drill holes to the water - conducting space 3 in the direction of the underground water flow source outside the underground chamber, that is, the first diversion hole 9; open holes in the chamber behind the heading face, and drill holes to the water - conducting space 3 in the direction of the underground water discharge outside the underground chamber, that is, the second diversion hole 10. Both the first diversion hole 9 and the second diversion hole 10 are located outside the excavation range of the underground chamber. The functions of the first diversion hole 9 and the second diversion hole 10 are to observe and reduce the pressure of the groundwater in the water - conducting space 3. Valves are set on the side of the underground chamber for the first diversion hole 9 and the second diversion hole 10. By opening the valves of the first diversion hole 9 and the second diversion hole 10, the flow rate of the diversion can be adjusted as needed to drain and relieve pressure.

[0037] S3. Install the diversion pipe 7 of the heading face 6. Install the diversion pipe 7 of the heading face 6. A valve may be provided on the diversion pipe 7 to adjust the flow rate of the diversion as needed, divert and relieve the water gushing from the heading face 6, and open the valve of the diversion pipe 7 to divert and relieve the pressure.

[0038] S4. Pour the flat pressure plug 8 of the heading face 6. Pour the flat pressure plug 8 behind the heading face 6 to block the previously exposed underground water gushing and ensure the stability of the rock mass between the water diversion space 3 and the heading face 6. After the strength of the flat pressure plug 8 meets the anti-water pressure requirements, the valve of the diversion pipe 7 can be closed during the plugging construction to provide a water-free working surface for the plugging construction.

[0039] S5. Set the steel grid in the water inflow direction of the water diversion space 3. Drill holes in the flat pressure plug 8, drill holes in the direction of the underground water flow source between the inner side of the first diversion hole 9 and the outside of the underground cave, the drill holes pass through the water diversion space 3 to the intact bedrock in front of the water diversion space, and insert steel pipes through the drill holes. Determine the number of steel pipes according to the size of the holes in the water diversion space. The spacing between the steel pipes is about 0.3 - 0.5 m, and a row of steel grid A11 is formed in the water inflow direction of the water diversion space 3.

[0040] S6. Grout the geotextile bag A13 in the water inflow direction of the water diversion space 3. Drill holes A12 parallel to the steel grid A11 outside the steel grid A11 of the flat pressure plug 8, the drill holes 12 lead to the water diversion space 3, place the geotextile bag A13 into the water diversion space 3 along the drill holes A12, and grout into the geotextile bag A13. The geotextile bag has the effect of permeable but impermeable to slurry, preventing the slurry from being washed away by the high-pressure water flow in the water diversion space 3. The slurry solidifies into a block. Due to the blocking of the steel grid A11, the geotextile bag A13 is prevented from being washed away by the water flow. Repeatedly grout the geotextile bag until the water volume and water pressure in the second diversion hole 10 decrease.

[0041] S7. If the structure of one row of steel grid + geotextile bag formed by S5 and S6 has a poor water control effect on the water coming from the upstream direction, then the number of rows of the steel grid A11 and the geotextile bag A13 can be increased adjacent to the upstream of the completed geotextile bag, and the multi-row spaced steel grid A11 and the geotextile bag A13 jointly play the role of bearing force and blocking water.

[0042] S8. Set the steel grid B14 in the water discharge direction of the water diversion space 3. Drill holes in the flat pressure plug 8, drill holes in the direction of the underground water flow discharge between the inner side of the second diversion hole 10 and the outside of the underground cave, the drill holes pass through the water diversion space 3 to the intact bedrock in front of the water diversion space, and insert steel pipes through the drill holes. Determine the number of steel pipes according to the size of the holes in the water diversion space. The spacing between the steel pipes is about 0.3 - 0.5 m, and a row of steel grid B14 is formed in the water discharge direction of the water diversion space 3.

[0043] S9. Grouting the drainage space 3 in the discharging direction into the formwork bag B16. Open holes on the inner side of the flat plug steel grid B14, set the drill holes B15 parallel to the steel grid B14, place the formwork bag B16 into the drainage space 3 along the drill holes B15, grout into the formwork bag B16, and the grout solidifies to form a block. Due to the blocking of the steel grid B14, it is prevented from being washed away by the water flow. Repeatedly perform formwork bag grouting until the water volume and water pressure in the second diversion hole 10 are greatly reduced.

[0044] S10. Pouring filling materials to fill the main holes in the drainage space 3. Divide the flat plug 8 into three areas: left, middle, and right. Drill holes C17, D18, and E19 in the three areas at intervals and from low to high in sequence, and close the valve of the diversion pipe 7. Pressurized concrete and other filling materials are sent into the drainage space 3 through the drill hole C17, and the filling materials gradually pile up. When slurry returns from the drill hole D18, close the drill hole C17, and change to send filling materials into the drainage space 3 through the drill hole D18 under pressure, and the filling materials gradually pile up. When slurry returns from the drill hole E19, close the drill hole D18, and change to send filling materials into the drainage space 3 through the drill hole E19 under pressure, and the filling materials gradually pile up. This step is carried out in a cycle until the main holes in the drainage space 3 are filled densely.

[0045] S11. System grouting in front of the heading face 6 of the underground project 1 and the surrounding rock 2. Systematically arrange grouting holes 20 in a radial pattern in front of the flat plug 8, and perform system grouting on the rock mass in front of the heading face 6 and the surrounding rock 2 in front of the cavern to completely block the water conduction channels, and a stable consolidation ring 21 is formed in the surrounding rock 2 of the underground cavern.

[0046] S12. Close the first diversion hole 9 and the second diversion hole 10, and excavate the underground cavern through the water gushing area.

[0047] When the width of the drainage space 3 > 0.5 m, construct according to the steps of S1 to S12. When the width of the drainage space 3 ≤ 0.5 m, remove steps S5 and S8 in S1 to S12, that is, there is no need to set steel grids in the water inflow and discharging directions. Because when the width of the drainage space 3 ≤ 0.5 m, after placing the formwork bag into the drainage space 3 through the drill hole, due to the relatively narrow width of the drainage space 3, the formwork bag can be fixed by the rock masses on both sides of the drainage space 3, so there is no need to set steel grids.

[0048] The present invention aims at the problem of concentrated water gushing from karst underground rivers, pipelines or fault open fractures and fractured zones in the surrounding rock or in front of the heading face within a relatively short range (distance less than 50 m) during the excavation of underground projects, tunnels, and tunnels. Because if the water conduction channel is located more than 50 m outside the surrounding rock 2 or in front of the heading face 6, the intact rock mass with a thickness of 50 m is sufficient to ensure that there will be no underground space water gushing problem and no treatment is required.

[0049] The construction working face of the present invention is located at the heading face 6 of the excavated underground space, rather than the ground surface or the floor of the underground project. The groundwater channel is close to the elevation of the working face, and a horizontal or inclined directional drilling scheme needs to be adopted to control the drilling direction during the construction process.

[0050] The applicable object of the present invention is "plugging the water inrush problem of underground spaces such as underground projects, tunnels, and tunnels located below the groundwater level". Both the working face and the plugging object are located below the groundwater level, that is, underwater construction operations, and the diversion scheme is crucial. The invention content includes taking reliable measures to control the flow rate and pressure of the water flow at the water plugging working face, preventing sudden water inrush, and ensuring construction safety.

[0051] In the present invention, upstream and downstream cofferdams are formed by steel grids + upstream formwork bags of the steel grids in the water inlet and outlet directions of the water diversion channel, and the water diversion space 3 is filled within the cofferdams. The upstream cofferdam undertakes the role of blocking groundwater. After the upstream cofferdam, the holes in the water diversion space are filled to avoid the erosion of the filling material by high-pressure water flow. The downstream cofferdam undertakes the role of blocking the filling material.

[0052] The excavation of the underground project 1 of the present invention needs to pass through the successfully plugged concentrated groundwater channel, and a reliable water-blocking consolidation circle 21 is formed outside the boundary of the surrounding rock 2 of the underground space to ensure the safe excavation passage and long-term stable operation of the underground project 1.

Claims

1. A method for plugging concentrated water inrush channels in underground engineering, characterized in that: It includes the following steps: S1. When the underground engineering (1) is excavated to the heading face (6), it is necessary to detect in advance whether there is a water-conducting space (3) in front of the heading face (6). If it exists, its scale and the direction of underground water flow (4) should be determined. When the exposure of the heading face (6) will cause water inrush in the water-conducting space (3) or its branch channels (5), stop the excavation; S2. Set diversion holes: Open holes in the chamber behind the heading face (6), and drill holes towards the direction of the underground water source outside the underground chamber into the water-conducting space (3), that is, the first diversion hole (9); Open holes in the chamber behind the heading face, and drill holes towards the direction of the underground water discharge outside the underground chamber into the water-conducting space (3), that is, the second diversion hole (10); S3. Install the diversion pipe (7) of the heading face (6) to divert and relieve the water inrush of the heading face (6); S4. Pour a pressure-balancing plug (8) behind the heading face (6) to block the previously exposed underground water inrush; S5. Set steel grids in the water source direction of the water-conducting space (3): Open holes in the pressure-balancing plug (8), and drill holes in the direction of the underground water source between the inside of the first diversion hole (9) and the outside of the underground chamber. The drill holes pass through the water-conducting space (3) to the intact bedrock in front of the water-conducting space (3). Insert steel pipes through the drill holes, and determine the number of steel pipes according to the size of the holes in the water-conducting space to form a row of steel grid A (11) in the groundwater source direction of the water-conducting space (3); S6. Grout the water source direction of the water-conducting space (3) with a formwork bag: Open holes outside the steel grid A (11) of the pressure-balancing plug (8), set drill holes A (12) parallel to the steel grid A (11), the drill holes A (12) lead to the water-conducting space (3), place the formwork bag A (13) into the water-conducting space (3) along the drill holes A (12), and grout into the formwork bag A (13). Repeatedly carry out formwork bag grouting until the water volume and water pressure in the second diversion hole (10) decrease; S7. Set steel grids in the water discharge direction of the water-conducting space (3): Open holes in the pressure-balancing plug (8), and drill holes in the direction of the underground water discharge between the inside of the second diversion hole (10) and the outside of the underground chamber. The drill holes pass through the water-conducting space (3) to the intact bedrock in front of the water-conducting space (3). Insert steel pipes through the drill holes, and determine the number of steel pipes according to the size of the holes in the water-conducting space to form a row of steel grid B (14) in the groundwater discharge direction of the water-conducting space (3); S8. Grout the water discharge direction of the water-conducting space (3) with a formwork bag: Open holes inside the steel grid B (14) of the pressure-balancing plug (8), set drill holes B (15) parallel to the steel grid B (14), the drill holes B (15) lead to the water-conducting space (3), place the formwork bag B (16) into the water-conducting space (3) along the drill holes B (15), and grout into the formwork bag B (16). Repeatedly carry out formwork bag grouting until the water volume and water pressure in the second diversion hole (10) are greatly reduced; S9. Filling the main holes in the water-conducting space (3) with perfusion filling material: Divide the flat pressure plug (8) into three areas, and drill holes C (17), D (18), and E (19) are respectively set in the three areas. There are multiple drill holes C (17), D (18), and E (19) arranged from low to high. First, send the filling material under pressure through drill hole C (17) to fill the water-conducting space (3). The filling material gradually piles up. When slurry returns from drill hole D (18), close drill hole C (17), and change to send the filling material under pressure through drill hole D (18) to fill the water-conducting space (3). The filling material gradually piles up. When slurry returns from drill hole E (19), close drill hole D (18), and change to send the filling material under pressure through drill hole E (19) to fill the water-conducting space (3). The filling material gradually piles up. This step is cycled until the main holes in the water-conducting space (3) are filled densely; S10. System grouting in front of the heading face (6) of the underground project (1) and the surrounding rock (2): Radially arrange grouting holes (20) in front of the flat pressure plug (8), and conduct system grouting on the rock mass in front of the heading face (6) and the surrounding rock (2) in front of the underground chamber to completely block the water-conducting channels, and a stable consolidation ring (21) is formed in the surrounding rock (2) of the underground chamber; S11. Close the first diversion hole (9), and the underground chamber is excavated through the water-inrush area.

2. The method for plugging the concentrated water-inrush channel of the underground project according to claim 1, characterized in that: Valves are provided on the first diversion hole (9) and the second diversion hole (10) on the side of the underground chamber, and the flow rate of the diversion is adjusted as needed.

3. The method for plugging the concentrated water-inrush channel of the underground project according to claim 1, characterized in that: After S6, if the structure of 1 row of steel grids + geotextile bags formed by S5 and S6 has a poor water control effect on the water coming from the upstream direction, then increase the number of rows of steel grid A (11) and geotextile bag A (13) adjacent to the upstream of the completed geotextile bag.

4. The method for plugging the concentrated water-inrush channel of the underground project according to claim 1, characterized in that: During the setting of the steel grid, the distance between adjacent steel pipes is 0.3 - 0.5 m.

5. The method for plugging the concentrated water-inrush channel of the underground project according to claim 1, characterized in that: In S1, when the underground project (1) is excavated to the heading face (6), it is necessary to detect in advance whether there is a water-conducting space (3) within 50 m in front of the heading face (6). If it exists, the subsequent steps are carried out. If it does not exist or the water-conducting space (3) exists only beyond 50 m, then directly carry out normal excavation.

6. The method for plugging the concentrated water-inrush channel of the underground project according to claim 1, characterized in that: In S3, a valve is installed on the diversion pipe (7) during the installation process. In S4, after the strength of the flat pressure plug (8) meets the anti-water pressure requirement, the valve of the diversion pipe (7) is closed during the plugging construction to provide a water-free working surface for the plugging construction.

7. The method for plugging the concentrated water-inrush channel of the underground project according to claim 1, characterized in that: When the width of the water guiding space (3) > 0.5 m, the construction is carried out according to the steps of S1 to S11; when the width of the water guiding space (3) ≤ 0.5 m, after removing steps S5 and S7 in S1 to S11, the construction is carried out.

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