Method for grouting small-section multi-angle hole arrangement curtain

Abstract

The invention discloses a small-section multi-angle hole arrangement curtain grouting method which comprises the following steps: (1) grouting pipes are uniformly driven into a bottom plate of a working section of an inclined roadway and within a contour line of the working section of the inclined roadway, and the grouting pipes are provided with different inclination angles, so that the grouting pipes are spread out of the contour line of the roadway; the setting of the inclination angle of the grouting pipe enables the end holes of the grouting pipe to be distributed at different distances outside the contour line of the roadway; and (2) grouting materials are adopted and injected from the grouting pipes, and the waterproof curtain is formed outside the roadway contour line in a diffusion shape. The small-section multi-angle hole arrangement curtain grouting method has the advantages of being easy to operate, high in construction efficiency and the like, and the purpose of grouting and water plugging of the main inclined shaft passing through the sandstone section is achieved through the hole arrangement mode that the tangent lines of the end holes of the drilled holes are arranged in a crossed mode.

Description

Technical Field

[0001] The invention belongs to the technical field of mine construction, and in particular relates to a method for hole-laying curtain grouting. Background Art

[0002] With the increase in the depth of coal mining, a large number of deep shafts are being or will be put into construction. The hydrogeological conditions after mining in deep areas are very complex. There are many bedrock aquifers, and the pores (cracks) are rich in water and the formation stability is poor. The risk of water inrush in the shaft is also increasing. A large amount of groundwater suddenly gushes out, forming interconnected cracks and channels in the rock mass, forming underground rivers or underground lakes, which seriously threaten the safety of construction.

[0003] Pre-grouting of the main inclined shaft working face is a relatively mature method of water prevention and control in China. Grouting water control at the working face is to inject grouting slurry into the rock formation by making holes, and use the grouting pressure to diffuse the slurry into the cracks of the surrounding rock, blocking the water in the rock body outside the grouting range, so that the rock body forms a reinforcement belt, that is, a grouting curtain, thereby improving the integrity of the rock body and enhancing the strength of the surrounding rock. However, the traditional grouting hole arrangement method has a single grouting effect, insufficient slurry diffusion, and poor water blocking effect in complex formations. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a method for small-section multi-angle hole curtain grouting with good water-blocking effect.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for small-section multi-angle hole curtain grouting, comprising the following steps: (1) Grouting pipes are evenly driven under the bottom plate of the inclined tunnel working section and within the contour line of the inclined tunnel working section. Different inclination angles are set for each grouting pipe so that it is diffused outside the tunnel contour line. The inclination angles of the grouting pipes are set so that the terminal holes of the grouting pipes are distributed at different distances outside the tunnel contour line. Even if it is diffused, a multi-point grouting water blocking curtain is formed on the external tangent line within 5 meters outside the tunnel contour line to achieve the grouting water blocking effect. (2) Use grouting materials, inject them from the grouting pipe, and diffuse them outside the tunnel contour to form a water-stop curtain.

[0006] In the above-mentioned method of small-section multi-angle curtain grouting, preferably, a plurality of grouting pipes are evenly arranged under the bottom plate of the inclined tunnel working section, and each grouting pipe is set at an angle downward, left or right so that the final hole is controlled at different distances outside the tunnel contour line, and grouting pipes at different distances are alternately arranged.

[0007] In the above-mentioned method of small-section multi-angle curtain grouting, preferably, a circle of grouting pipes is evenly arranged within and close to the contour line of the working section of the inclined tunnel, and each grouting pipe is set at an angle downward, left or right so that the final hole is controlled at different distances outside the tunnel contour line, and grouting pipes at different distances are alternately set.

[0008] In the above-mentioned method of curtain grouting with multi-angle holes in small section, preferably, 1#, 2#, 3#, 4#, 5#, and 6# grouting pipes are evenly arranged 1m below the bottom plate of the working section of the inclined tunnel, so that the terminal holes of the 1#, 3#, and 5# grouting pipes are 5m outside the tunnel contour line, and the terminal holes of the 2#, 4#, and 6# grouting pipes are 4m outside the tunnel contour line; 7#, 8#, 9#, 10#, 11#, 12#, 13#, 14#, 15#, 16#, 17#, and 18# grouting pipes are evenly arranged within the contour line of the working section of the inclined tunnel and close to the contour line of the working section of the inclined tunnel, so that 7#, The terminal holes of 15# and 17 grouting pipes are 1m outside the outline of the roadway, and the terminal holes of 16# and 18# grouting pipes are 0m outside the outline of the roadway; 19#, 20#, 21#, 22#, and 23# grouting pipes are evenly arranged within 7#, 8#, 9#, 10#, 11#, 12#, 13#, 14#, 15#, 16#, 17#, and 18# grouting pipes at 0.5m from the outline of the working section of the inclined roadway, and the terminal holes of 19# and 23# grouting pipes are 5m outside the outline of the roadway, and the terminal holes of 20#, 21#, and 22# grouting pipes are 4m outside the outline of the roadway. The above-mentioned grouting hole setting method adopted by the present invention can achieve a better water blocking effect by setting a plurality of evenly arranged grouting pipes, and the above-mentioned specific method is more suitable for the situation of water discharge at the bottom plate of the roadway.

[0009] In the above-mentioned method of small-section multi-angle hole curtain grouting, preferably, an inspection hole is arranged in the middle of the working section of the inclined tunnel, and the inclination angle of the inspection hole is the same as that of the inclined tunnel.

[0010] In the above-mentioned method of small-section multi-angle hole curtain grouting, preferably, the method specifically comprises the following steps: S1. Drilling: Drill holes in the working section of the inclined tunnel according to the design. After drilling, install the telescopic grouting sealer and connect the grouting pipe in time; S2. Install ball valve and grouting pipeline: first install ball valve, then connect high-pressure grouting pipe, high-pressure grouting pipe and grouting pump grouting valve; S3. Water pressure test: After the pipeline is connected, start the pump to inject water under pressure to measure the pipeline performance and effectively flush the cracks to facilitate the flow of slurry; S4. Grouting: First inject thin slurry, then inject thick slurry, increase the slurry absorption of a single hole, use double-liquid slurry for plugging grouting, and change holes for grouting when the water blocking effect is achieved.

[0011] In the above-mentioned method of curtain grouting with small cross-section and multi-angle holes, preferably, the water absorption per unit borehole is calculated according to the water pressure test result of step S3, and the type of slurry and the initial concentration of the slurry are selected accordingly. When the water absorption rate is greater than 10L.min -1 m -1 The slurry is cement-water glass double liquid slurry, the initial concentration of cement slurry is 1:1, and when the water absorption rate is 7-10L.min -1 m -1 When the slurry is single-liquid cement slurry, the initial concentration of cement slurry is 1:1, and the water absorption rate is 5-7L.min -1 m -1 When the slurry is single-liquid cement slurry, the initial concentration of cement slurry is 2:1, and the water absorption rate is 3-5L.min -1 m -1 When using, the slurry is single-liquid cement slurry or ultra-fine cement slurry, and the initial concentration of the cement slurry is 3:1.

[0012] In the above-mentioned method of curtain grouting with small cross-section and multi-angle holes, preferably, the grouting material includes cement slurry and Baiyin brand grouting material slurry, and the Baiyin brand grouting material slurry is obtained by mixing any one of Baiyin brand BY12-VI non-dispersible grouting material when in contact with water, BY12-IA early setting and early strength high strength grouting material, BY12-I high performance non-shrinkage grouting material and BY12-7 gas sealing hole special grouting material with water. This kind of material has slight expansion, high early strength, strong impermeability, and the water inflow of the working face is not easy to rebound after the grouting is completed, and it has a significant effect on the open water eyes with large water output.

[0013] In the above-mentioned small-section multi-angle curtain grouting method, preferably, the weight water-cement ratio of the cement slurry is 1:0.8-1:1, the weight water-cement ratio of the Baiyin brand grouting material slurry is 0.27:1, and the volume ratio of the cement slurry to the Baiyin brand grouting material slurry is 1:0.8-1:1.

[0014] In the above-mentioned method of curtain grouting with small cross-section and multi-angle holes, preferably, in step S4, thin slurry is injected first and then thick slurry is injected. The actual operation is to use 10-15Be' water glass slurry when starting grouting, 20-25Be' water glass slurry when normal grouting, and 36-40Be' water glass slurry or original solution to seal the hole when grouting the final hole.

[0015] In the above-mentioned method of small-section multi-angle curtain grouting, preferably, the grouting pressure is 2-4 times the hydrostatic pressure at the grouting point, and the grouting is stopped after stabilization for 15 minutes, and this is repeated until there is no obvious water discharge from the working surface.

[0016] In the above-mentioned method of curtain grouting with multi-angle holes in small sections, preferably, the injection amount of pre-grouting slurry in the working section of the inclined tunnel is calculated as follows: ; Where: Q is the total amount of slurry injected into the wellbore, m 3 ; B is the number of grouting holes in the wellbore; R is the effective diffusion radius of the slurry, m, and is taken as 2-3m; H is the length of the grouting section, m; n is the fracture ratio of water-bearing rock formation, %; λ is the slurry loss coefficient, which is 1.1-1.4; N is the serous stone coefficient, which is 0.75-0.85.

[0017] The curtain grouting method for multi-angle hole arrangement of small section in the working face of water-rich inclined shaft of the present invention adopts a new hole arrangement mode and multi-angle hole arrangement. The terminal hole positions of deep and shallow holes are within the tangent line within the range of 5 meters outside the outline line of the tunnel to form a multi-point grouting and water blocking curtain, so as to achieve the grouting and water blocking effect. Under the premise of ensuring that the grouting effect remains unchanged, the effective grouting length is increased and the grouting time is reduced.

[0018] The multi-angle hole arrangement method of the present invention can provide grouting holes at 5m, 4m, 1m, and 0m of the outer contour of the tunnel, ensuring that the slurry is diffused at more angles, which can better reinforce water blocking and achieve better water blocking effect.

[0019] Compared with the prior art, the advantages of the present invention are: The method of curtain grouting with multi-angle holes in small sections of the present invention has the advantages of simple operation and high construction efficiency. The purpose of grouting and water blocking in the sandstone section of the main inclined shaft is achieved through the hole arrangement method of the tangent line of the final hole of the drilling. The new hole arrangement method saves costs and reduces engineering costs. Under the influence of actual construction conditions, the engineering innovation of controlling large-section excavation by grouting with small-section holes is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 Schematic diagram of the drilling plane layout in the embodiment.

[0022] Figure 2 It is a stereoscopic diagram of the main inclined shaft and grouting holes in the embodiment. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0024] It should be noted that when an element is described as being "fixed, fixed, connected or connected to" another element, it can be directly fixed, fixed, connected or connected to the other element, or it can be indirectly fixed, fixed, connected or connected to the other element through other intermediate connectors.

[0025] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0026] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0027] Example: A method for small-section multi-angle hole curtain grouting, comprising the following steps: (1) Grouting pipes are evenly driven under the bottom plate of the inclined tunnel working section and within the contour line of the inclined tunnel working section. Each grouting pipe is set at a different inclination angle so that it is diffused outside the tunnel contour line; the inclination angle of the grouting pipe is set so that the terminal holes of the grouting pipes are distributed at different distances outside the tunnel contour line; (2) Use grouting materials, inject them from the grouting pipe, and diffuse them outside the tunnel contour to form a water-stop curtain.

[0028] In this embodiment, multiple grouting pipes are evenly arranged under the bottom plate of the inclined tunnel working section. Each grouting pipe is set at an angle downward, left or right so that the final hole is controlled at different distances outside the tunnel contour line. Grouting pipes at different distances are set alternately.

[0029] In this embodiment, a circle of grouting pipes is evenly arranged within and close to the contour line of the working section of the inclined tunnel. Each grouting pipe is set at an angle downward, left or right so that the final hole is controlled at different distances outside the tunnel contour line. Grouting pipes at different distances are set alternately.

[0030] In this embodiment, an inspection hole is arranged in the middle of the working section of the inclined tunnel, and the inclination angle of the inspection hole is the same as that of the inclined tunnel.

[0031] The method of small-section multi-angle hole curtain grouting of this embodiment specifically includes the following steps: S1. Drilling: Drill holes in the working section of the inclined tunnel according to the design. After drilling, install the telescopic grouting sealer and connect the grouting pipe in time; S2. Install ball valve and grouting pipeline: first install ball valve, then connect high-pressure grouting pipe, high-pressure grouting pipe and grouting pump grouting valve; S3. Water pressure test: After the pipeline is connected, start the pump to inject water under pressure to measure the pipeline performance and effectively flush the cracks to facilitate the flow of slurry; S4. Grouting: First inject thin slurry, then inject thick slurry, increase the slurry absorption of a single hole, use double-liquid slurry for plugging grouting, and change holes for grouting when the water blocking effect is achieved.

[0032] In this embodiment, the water absorption per unit borehole is calculated according to the water pressure test result of step S3, and the type of slurry and the initial concentration of the slurry are selected accordingly. When the water absorption rate is greater than 10L.min -1 m -1 When the slurry is cement-water glass double liquid slurry, the water absorption rate is 7-10L.min -1 m -1 When the slurry is single-liquid cement slurry, the water absorption rate is 5-7L.min -1 m -1 When the slurry is single-liquid cement slurry, the water absorption rate is 3-5L.min -1 m -1 When using, the slurry is single-liquid cement slurry or superfine cement slurry.

[0033] In this embodiment, the grouting material includes cement slurry and Baiyin brand grouting material slurry. The Baiyin brand grouting material slurry is obtained by mixing any one of Baiyin brand BY12-VI type non-dispersible grouting material when in contact with water, BY12-IA type early-setting and early-strength high-strength grouting material, BY12-I type high-performance non-shrinkage grouting material and BY12-7 type gas sealing hole special grouting material with water.

[0034] In this embodiment, the weight water-cement ratio of the cement slurry is 1:0.8-1:1, the weight water-cement ratio of the Baiyin brand grouting material slurry is 0.27:1, and the volume ratio of the cement slurry to the Baiyin brand grouting material slurry is 1:0.8-1:1.

[0035] In this embodiment, the injection amount of pre-grouting slurry in the inclined tunnel working section is calculated as follows: ; Where: Q is the total amount of slurry injected into the wellbore, m 3 ; B is the number of grouting holes in the wellbore; R is the effective diffusion radius of the slurry, m, and is taken as 2-3m; H is the length of the grouting section, m; n is the fracture ratio of water-bearing rock formation, %; λ is the slurry loss coefficient, which is 1.1-1.4; N is the serous stone coefficient, which is 0.75-0.85.

[0036] More specifically, a specific construction method is provided as follows: During the grouting construction of a mine owner's inclined shaft, due to the limitations of on-site construction conditions, a short injection and short excavation grouting method was adopted to safely pass through the sandstone aquifer. The inclined shaft was designed to have a slope of 19.8° downhill, and the actual construction floor was located 2.4 meters below the tunnel roof, with a straight wall and semicircular arch section. In order to timely grasp the rock water content within 20m in front of the working face and perform grouting to block water, a grouting scheme combining a new hole arrangement method and double liquid slurry is adopted.

[0037] Specifically, Figure 1 , Figure 2 As shown, 1#, 2#, 3#, 4#, 5#, and 6# grouting pipes are evenly arranged 1m below the bottom plate of the inclined tunnel working section, so that the terminal holes of 1#, 3#, and 5# grouting pipes are 5m outside the tunnel contour line, and the terminal holes of 2#, 4#, and 6# grouting pipes are 4m outside the tunnel contour line; 7#, 8#, 9#, 10#, 11#, 12#, 13#, 14#, 15#, 16#, 17#, and 18# grouting pipes are evenly arranged within and close to the contour line of the inclined tunnel working section, so that the terminal holes of 7#, 15#, and 17# grouting pipes are 5m outside the tunnel contour line, and the terminal holes of 2#, 4#, and 6# grouting pipes are 4m outside the tunnel contour line. The end hole is 1m outside the tunnel outline, and the end holes of 16# and 18# grouting pipes are 0m outside the tunnel outline; 19#, 20#, 21#, 22# and 23# grouting pipes are evenly arranged within 7#, 8#, 9#, 10#, 11#, 12#, 13#, 14#, 15#, 16#, 17# and 18# grouting pipes at 0.5m away from the outline of the working section of the inclined tunnel. The end holes of 19# and 23# grouting pipes are 5m outside the tunnel outline, and the end holes of 20#, 21# and 22# grouting pipes are 4m outside the tunnel outline.

[0038] When designing the drilling positions, 6 grouting holes were arranged 1 meter behind the bottom plate of the working face, with a hole center distance of 1.28m, named holes 1#-6#. 9 grouting holes were evenly arranged on the contour line of the tunnel, with a hole center distance of 1.06m, named holes 7#-15#, 3 holes were arranged with a spacing of 1.375m below the contour line of the tunnel, named holes 16#-18#, 5 holes were arranged 0.5m within the contour line of the tunnel working face, with a hole center distance of 1.48m, named holes 19#-23#, 2 holes were arranged at appropriate positions in the tunnel section, and they were constructed along the tunnel, named holes 24# and 25#, totaling 25 grouting holes this time (of which 24# and 25# grouting holes also serve as inspection holes).

[0039] The detailed parameters of the above drilling angles and hole depths are shown in Table 1 below.

[0040] Table 1: Detailed parameters of drilling angle and hole depth

[0041] Among them, the final holes of holes 1#, 3#, 5#, 9#, 11#, 13#, 19# and 23# are 5m away from the outer contour line of the tunnel; the final holes of holes 2#, 4#, 6#, 8#, 10#, 12#, 14#, 20#, 21# and 22# are 4m away from the outer contour line of the tunnel; the final holes of holes 7#, 15# and 17 are 1m away from the outer contour line of the tunnel; and the final holes of holes 16# and 18# are 0m away from the outer contour line of the tunnel.

[0042] The grouting slurry is prepared as follows: 1. Preparation of cement slurry: The water-cement ratio of cement slurry is 1:0.8-1 (weight ratio).

[0043] 2. Preparation of Baiyin brand BY12 grouting material slurry: the water-cement ratio of the slurry is 0.27:1 (weight ratio).

[0044] 3. Preparation of water glass slurry: The ratio of slurry to water glass slurry is 1:0.8-1 (volume ratio).

[0045] In order to increase the stone setting rate of the slurry, use fresh bagged P·O42.5 grade ordinary Portland cement; when the water temperature of the main inclined shaft is too high and the solidification effect of ordinary Portland cement is poor, use fresh bagged BY12-IA type early-setting and early-strength high-strength grouting material or BY12-I type high-performance non-shrinkage grouting material.

[0046] According to the measured hydrostatic pressure, the final grouting pressure of the working face is determined to be 10MPa-20MPa.

[0047] The calculation shows that the pre-grouting slurry injection volume of the working face is Q=366.25m 3 .

[0048] The grouting equipment used is the 2TGZ-130 / 130 dual-liquid speed-regulated high-pressure grouting pump and the GS-700 vertical high-speed grouting machine that matches the pump.

[0049] Grouting construction 1. Drilling: First drill holes on the working surface according to the design. After drilling, install the telescopic grouting sealer in time and connect the grouting tail pipe.

[0050] 2. Installation of ball valve and grouting pipeline: first install the ball valve, and then connect the high-pressure grouting pipe, high-pressure grouting pipe and grouting pump outlet valve, etc.

[0051] 3. Water pressure test: After the pipeline is connected, start the pump to inject water under pressure to measure the pipeline performance and effectively flush the cracks (gaps) to facilitate the flow of slurry.

[0052] 4. Grouting: First inject thin slurry, then thick slurry, to increase the slurry absorption of a single hole. Use double liquid slurry for plugging grouting, and change the hole for grouting when the water plugging effect is achieved. When starting grouting, use 10-15Be' water glass slurry, when grouting normally, use 20-25Be' water glass slurry, and when grouting the final hole, use 36-40Be' water glass slurry or original liquid to seal the hole.

[0053] After the grouting is completed, a certain amount of clean water should be pressed in to clean the slurry in the pump and pipeline. The residual slurry in the pipeline should be put into the mine car and lifted to the ground for discharge. After each grouting, the equipment and pipelines should be cleaned, inspected and tested to prepare for the next grouting.

[0054] By adopting the above-mentioned grouting pipe structure and slurry, a good waterproofing effect can be achieved during the grouting construction process of the mine main inclined shaft.

Claims

1. A method for small-section multi-angle hole curtain grouting, characterized in that: The following steps are involved: (1) Grouting pipes are evenly driven under the bottom plate of the inclined tunnel working section and within the contour line of the inclined tunnel working section. Each grouting pipe is set at a different inclination angle so that it is diffused outside the tunnel contour line; the inclination angle of the grouting pipe is set so that the terminal holes of the grouting pipes are distributed at different distances outside the tunnel contour line; (2) Use grouting materials, inject them from the grouting pipe, and diffuse them outside the tunnel contour to form a water-stop curtain.

2. The method for curtain grouting with small cross-section and multi-angle holes according to claim 1 is characterized in that: Multiple grouting pipes are evenly arranged under the bottom plate of the inclined tunnel working section. Each grouting pipe is set at an angle downward, left or right so that the final hole is controlled at different distances outside the tunnel contour line. Grouting pipes at different distances are set alternately.

3. The method for curtain grouting with small cross-section and multi-angle holes according to claim 1, characterized in that: A circle of grouting pipes is evenly arranged within and close to the contour line of the working section of the inclined tunnel. Each grouting pipe is set at an angle downward, left or right so that the final hole is controlled at different distances outside the tunnel contour line. Grouting pipes at different distances are set alternately.

4. The method for curtain grouting with small cross-section and multi-angle holes according to claim 1 is characterized in that: Evenly arrange 1#, 2#, 3#, 4#, 5#, and 6# grouting pipes 1m below the bottom plate of the inclined tunnel working section, so that the terminal holes of 1#, 3#, and 5# grouting pipes are 5m outside the tunnel contour line, and the terminal holes of 2#, 4#, and 6# grouting pipes are 4m outside the tunnel contour line; evenly arrange 7#, 8#, 9#, 10#, 11#, 12#, 13#, 14#, 15#, 16#, 17#, and 18# grouting pipes within and near the contour line of the inclined tunnel working section, so that the terminal holes of 7#, 15#, and 17# grouting pipes are 5m outside the tunnel contour line, and the terminal holes of 2#, 4#, and 6# grouting pipes are 4m outside the tunnel contour line. At 1m outside the tunnel outline, the end holes of 16# and 18# grouting pipes are at 0m outside the tunnel outline; within 7#, 8#, 9#, 10#, 11#, 12#, 13#, 14#, 15#, 16#, 17#, and 18# grouting pipes, 19#, 20#, 21#, 22#, and 23# grouting pipes are evenly arranged at 0.5m from the outline of the working section of the inclined tunnel. The end holes of 19# and 23# grouting pipes are 5m outside the tunnel outline, and the end holes of 20#, 21#, and 22# grouting pipes are 4m outside the tunnel outline.

5. The method for curtain grouting with small cross-section and multi-angle holes according to claim 1, characterized in that: An inspection hole is arranged in the middle of the working section of the inclined tunnel, and the inclination angle of the inspection hole is the same as that of the inclined tunnel.

6. The method for small-section multi-angle hole curtain grouting according to any one of claims 1 to 5, characterized in that: The specific steps include: S1. Drilling: Drill holes in the working section of the inclined tunnel according to the design. After drilling, install the telescopic grouting sealer and connect the grouting pipe in time; S2. Install ball valve and grouting pipeline: first install ball valve, then connect high-pressure grouting pipe, high-pressure grouting pipe and grouting pump grouting valve; S3. Water pressure test: After the pipeline is connected, start the pump to inject water under pressure to measure the pipeline performance and effectively flush the cracks to facilitate the flow of slurry; S4. Grouting: First inject thin slurry, then inject thick slurry, increase the slurry absorption of a single hole, use double-liquid slurry for plugging grouting, and change holes for grouting when the water blocking effect is achieved.

7. The method for curtain grouting with small cross-section and multi-angle holes according to claim 6 is characterized in that: According to the water pressure test results of step S3, the water absorption per unit borehole is calculated, and the type of slurry and the initial concentration of the slurry are selected accordingly. When the water absorption rate is greater than 10L.min -1 m -1 When the slurry is cement-water glass double liquid slurry, the water absorption rate is 7-10L.min -1 m -1 When the slurry is single-liquid cement slurry, the water absorption rate is 5-7L.min -1 m -1 When the slurry is single-liquid cement slurry, the water absorption rate is 3-5L.min -1 m -1 When using, the slurry is single-liquid cement slurry or superfine cement slurry.

8. The method for curtain grouting with small cross-section and multi-angle holes according to claim 6, characterized in that: The grouting materials include cement slurry and Baiyin brand grouting material slurry. The Baiyin brand grouting material slurry is made by mixing any one of Baiyin brand BY12-VI non-dispersible grouting material when in contact with water, BY12-IA early-setting and early-strength high-strength grouting material, BY12-I high-performance non-shrinkage grouting material and BY12-7 gas sealing hole special grouting material with water.

9. The method for curtain grouting with small cross-section and multi-angle holes according to claim 6, characterized in that: The weight water-cement ratio of cement slurry is 1:0.8-1:1, the weight water-cement ratio of Baiyin brand grouting material slurry is 0.27:1, and the volume ratio of cement slurry to Baiyin brand grouting material slurry is 1:0.8-1:

1.

10. The method for curtain grouting with small cross-section and multi-angle holes according to claim 6, characterized in that: The injection amount of pre-grouting slurry in the working section of the inclined tunnel is calculated as follows: ； Where: Q is the total amount of slurry injected into the wellbore, m 3 ; B is the number of grouting holes in the wellbore; R is the effective diffusion radius of the slurry, m, and is taken as 2-3m; H is the length of the grouting section, m; n is the fracture ratio of water-bearing rock formation, %; λ is the slurry loss coefficient, which is 1.1-1.4; N is the serous stone coefficient, which is 0.75-0.85.

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