A tunnel water blocking construction method

Abstract

The present invention relates to a method for water blocking in a tunnel, comprising the following steps: 1) constructing a bag pile hole connected to a tunnel from the ground downward, wherein the bag pile hole is located in front of the tunnel face; 2) after lifting the drill, wrapping a bag on the outside of the drill rod and lowering it from the bag pile hole into the tunnel, pouring slurry into the bag through the drill rod to expand the bag, and after the slurry solidifies, lifting the drill rod and forming a bag pile for water blocking in the tunnel. The bag pile hole is constructed from the ground downward and the drill rod wrapped with the bag is lowered to form the bag pile, thereby achieving the purpose of water blocking. The bag ensures that the slurry will not be dispersed, and the drill rod can play a bending resistance role, thereby ensuring that the bag is not washed away by the gushing water, and then solidifying at a designated position to form a bag pile. Since the bag pile is formed by pouring slurry from the ground downward, it is not necessary for humans or machines to enter the tunnel for construction, and it can be applied to scenes with large gushing water to achieve water blocking.

Description

Technical Field

[0001] The present invention generally relates to the technical field of dynamic water blocking and more specifically to a tunnel water blocking construction method. Background Art

[0002] During tunnel construction, construction in poor geological sections may sometimes encounter sudden water surges, causing damage to the existing pumping and drainage system and causing flooding. The conventional construction plan is "drainage first, then plugging", that is, first organize pumping and drainage construction, and then grouting and plugging water in the tunnel. However, when the dynamic reserve is particularly large and the water supply is abundant, it is impossible or impossible to drain it all by strong drainage. The "drainage first, then plugging" plan is used for construction, which not only has high project costs, but also makes it difficult to guarantee the construction period.

[0003] The prior art also uses a blocking method as shown in the invention patent application with application publication number CN113446059A, in which a cofferdam is arranged in the vertical direction 2-3m in front of the heading face using cofferdam bags, a water diversion pipe is laid after the cofferdam is arranged, and a geotextile is laid on the inside of the cofferdam, and then the inside of the geotextile is grout-filled with underwater non-dispersible materials, and finally a water-stop retaining wall is obtained, thereby achieving sudden water blocking.

[0004] This plugging method first sets up a cofferdam in the tunnel and then uses grouting to seal it. However, in actual application, as the amount of water gushing increases, the heading face will be directly submerged and the water level will continue to rise. At this time, it is impossible to set up a cofferdam with cofferdam bags in the tunnel and complete the water blocking. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a tunnel water blocking construction method to solve the technical problem in the prior art that water blocking cannot be performed when the amount of water gushing out is large.

[0006] To achieve the above-mentioned purpose, the tunnel water blocking construction method provided by the present invention adopts the following technical scheme: A tunnel water blocking construction method, comprising the following steps:

[0007] 1) Constructing a bag pile hole connected to the tunnel from the ground downward, where the bag pile hole is located in front of the tunnel face;

[0008] 2) After the drill is lifted, a bag is wrapped around the outside of the drill rod and lowered into the tunnel through the bag pile hole, slurry is poured into the bag through the drill rod to expand the bag, and after the slurry solidifies, the drill rod is lifted up to form a bag pile for water blocking in the tunnel.

[0009] The beneficial effect is: constructing bag pile holes from the ground downward and lowering drill rods wrapped with bags to form bag piles, thereby achieving the purpose of water blocking. The bags ensure that the slurry will not be dispersed, and the drill rods can play a role in bending resistance, thereby ensuring that the bags are not washed away by the gushing water, and then solidifying at the designated position to form bag piles. Since the bag piles are formed by pouring slurry from the ground downward, the water blocking construction method of the present invention does not require manual or machine entry into the tunnel for construction, and can be applied to scenes with large water gushing to achieve water blocking. Moreover, the construction method of the present invention has a short construction period and no pollution to the water body. It can be set in locations with stable geological conditions. The setting method is flexible and can achieve long-distance directional drilling.

[0010] As a further improvement, in step 1), when constructing the bag pile hole, the drill bit drills into the set depth on the tunnel floor to form a floor drill hole on the tunnel floor; in step 2), the drill rod wrapped with the bag is lowered into the floor drill hole so that the bottom of the bag pile is inserted into the floor drill hole. The bottom of the bag pile is inserted into the floor drill hole, and the bag pile is blocked by the tunnel body, thereby improving the stability of the bag pile in the tunnel.

[0011] As a further improvement, the bag pile holes and the corresponding bag piles are arranged in plurality, and the bag piles are pressed against each other to form a bag pile group for water blocking. The bag pile group is formed by pressing against each other, and the water blocking effect is better.

[0012] As a further improvement, each bag pile hole is arranged in at least two rows along the extension direction of the tunnel, and any two adjacent rows of bag pile holes are staggered in a direction perpendicular to the extension direction of the tunnel. The staggered arrangement of each row of bag piles has a better squeezing effect, thereby enhancing the water blocking effect.

[0013] As a further improvement, a drill rod wrapped with a bag is first lowered into the bag pile hole located in the middle position and slurry is poured in to form a bag pile, and then bag piles are formed in sequence from the inside to the outside around the formed bag pile.

[0014] As a further improvement, a feeding hole connected to the tunnel is constructed from the ground downwards, wherein the feeding hole is located between the bag pile and the tunnel face; after the bag pile is formed, water blocking materials are fed into the tunnel from the feeding hole, and the bag pile is used to intercept the water blocking materials. By feeding the water blocking materials and accumulating them at the bag pile, the water blocking effect can be further enhanced.

[0015] As a further improvement, the water blocking material is an elastic expansion body that swells when exposed to water.

[0016] As a further improvement, after the bag pile is formed, a water blocking wall is constructed on one side of the bag pile close to the hole to block the water gushing. The water blocking wall further improves and enhances the water blocking effect.

[0017] As a further improvement, the tunnel is pumped out before the water blocking wall is constructed until the water level drops to a set height. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present application will become easy to understand. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0019] Figure 1 It is a schematic diagram of the drilling trajectory in the tunnel water blocking construction method of the present invention;

[0020] Figure 2 It is a schematic diagram of the arrangement of drilling holes in the tunnel water blocking construction method of the present invention;

[0021] Figure 3 This is the first schematic diagram after the tunnel water blocking construction method of the present invention is blocked;

[0022] Figure 4 It is a second schematic diagram after the tunnel water blocking construction method of the present invention is blocked;

[0023] Figure 5 It is a schematic diagram showing a water blocking wall in the tunnel water blocking construction method of the present invention;

[0024] Figure 6 It is a schematic diagram of a drill rod and a bag pile in the tunnel water blocking construction method of the present invention;

[0025] Figure 7 It is a schematic diagram of the arrangement of bag piles in the tunnel water blocking construction method of the present invention;

[0026] Figure 8 It is a force diagram of bag grouting in the tunnel water blocking construction method of the present invention.

[0027] Explanation of the accompanying reference numerals: 1. Tunnel; 2. Heading face; 3. Roof; 4. Bottom plate; 5. Drilling trajectory; 6. Bag pile hole; 7. Feeding hole; 8. Bag pile; 9. Water blocking wall; 10. Drain pipe; 11. Drill rod; 12. Expansion elastomer. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0029] In the tunnel water blocking construction method of the present invention, a hole is drilled downward from the ground, and a drill rod is wrapped with a bag and lowered into the tunnel through the hole. Slurry is poured into the bag through the drill rod and the bag is expanded. After the slurry solidifies, a water blocking bag pile is formed in the tunnel.

[0030] After introducing the basic principle of the present invention, various non-limiting embodiments of the present invention are described in detail below. The number of any element in the drawings is for illustration and not for limitation, and any naming is only for distinction and does not have any limiting meaning.

[0031] The principle and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0032] Embodiment 1 of the tunnel water blocking construction method provided by the present invention:

[0033] like Figures 1 to 8 As shown, the tunnel water blocking construction method of the present invention is aimed at the scenario of a large amount of water gushing at the face 2 in the tunnel 1. Due to the large amount of water gushing, it is impossible to directly construct a blocking structure in the tunnel 1 to complete the water blocking. The tunnel water blocking construction method of the present invention constructs a bag pile hole 6 from the ground, and lowers a drill rod 11 wrapped with a bag into the bag pile hole 6. After pouring slurry, a bag pile 8 is formed in the tunnel, and the bag pile 8 is used to block the water gushing in the tunnel 1. The tunnel water blocking construction method includes the following steps:

[0034] 1. Construct the bag pile holes 6 and the feeding holes 7 from the ground downwards, wherein the bag pile holes 6 and the feeding holes 7 are both connected to the tunnel 1 and are located in front of the tunnel face 2, and the bag pile holes 6 are located in front of the feeding holes 7, where the front here refers to the side close to the tunnel entrance. A total of 17 boreholes are designed in this embodiment, of which there are 13 bag pile holes 6 and 4 feeding holes 7, and the drilling trajectory 5 is as follows Figure 1 As shown. 17 boreholes are arranged in 7 rows along the front-to-back direction, and the horizontal spacing of the final holes of the 17 boreholes is 1.5m, and the vertical spacing is 3m. The drilling area is controlled within 100m from the heading face, and the rock within this range is stable and completed. The boreholes are arranged in a 3:2:3:2:3:2:2 manner from front to back, and the 13 bag pile holes 6 are divided into 5 rows. Any two adjacent rows of bag pile holes 6 are staggered perpendicular to the front-to-back direction. The purpose of this arrangement is to improve the water blocking effect. The construction sequence adopts the "flower arrangement interval" method. During construction, a drill bit is installed at the end of the drill rod 11 for drilling. The drill bit penetrates the top plate 3 of the tunnel 1 and penetrates into the bottom plate 4 of the tunnel 1 at a depth of 1-1.5m, forming a bottom plate borehole on the bottom plate 4 of the tunnel 1.

[0035] In this embodiment, all 17 boreholes adopt the "three-level aperture and two-level casing" structure. The first opening section has a diameter of φ444.5mm, and a φ406.4mm casing is inserted; the second opening section has a diameter of φ347.6mm, and a φ298.45mm casing is inserted; the third opening bare hole section has a diameter of φ250.8mm, and the total footage is approximately 6630m.

[0036] 2. After the construction of the bag pile hole 6 and the feeding hole 7 is completed, the drill rod 11 is lifted up and wrapped with a bag, wherein the bag is a flexible material, the upper end of the bag and the drill rod 11 are reliably sealed, and the bottom of the bag is closed. The drill rod 11 wrapped with the bag is lowered into the tunnel 1 through the bag pile hole 6 and the lower end is penetrated into the bottom plate borehole, wherein the penetration distance into the bottom plate borehole is about 1m. Then, Midwest KYQ fast-hardening lightweight grouting material is poured into the bag through the drill rod 11. After grouting, the bag expands to form a bag pile with a diameter greater than 1500mm (in actual use, the maximum expansion diameter of the bag pile can reach 4000mm according to site needs). After the slurry solidifies and reaches the design strength, the drill rod 11 is lifted out of the bag. The drill rod 11 plays a bending resistance role during the solidification process of the slurry.

[0037] Since there are 13 bag pile holes 6, the bag piles 8 will be squeezed against each other and against the wall of the tunnel 1 during the forming process, and together form a water-blocking bag pile group.

[0038] When forming the bag pile 8, first lower the drill rod 11 wrapped with the bag into the middle bag pile hole 6 in the middle row in the front-to-back direction. After the bag pile 8 is formed, the subsequent bag piles 8 are formed around the previous bag pile 8 to enhance the squeezing effect, thereby ensuring that the bag pile group can achieve water blocking.

[0039] The theoretical calculation of the bag pile 8 is as follows:

[0040] 1) Theoretical verification of water-stopping of bag pile groups

[0041] The diameter of the holes drilled by the bag pile 8 in the top plate 3 and the bottom plate 4 of the tunnel 1 is It is Φ130mm~Φ250mm, among which Φ127mm drill rod is the skeleton of bag pile. By consulting relevant information of drill rod, it can be known that the technical parameters of Φ127mm drill rod are shown in Table 1, and the technical parameters of grouting material are shown in Table 2.

[0042] Table 1 Technical parameters of Φ127mm drill pipe

[0043]

[0044] Table 2 Technical parameters of Midwest KYQ fast-hardening lightweight grouting material for bag piles

[0045]

[0046] From this, the shear load of each bag pile can be obtained =6042.3-6328.7kN.

[0047] Tunnel section width × height = 4.5m × 4.8m, arch section, calculated tunnel section area 19.4m 2 The water pressure limit value of the groundwater in the tunnel was obtained by on-site measurement. is 2.8MPa, and the number of bag piles is obtained =8.6-9.1.

[0048] At the same time, the uneven cross-section of the tunnel causes certain mechanical bite and friction. Taking a safety factor of 1.5, the number of bag piles is 13, which can ensure that the bag pile groups squeeze each other to block the underground water in the tunnel.

[0049] 2) Theoretical calculation of working strength of ultra-high strength bladder

[0050] The breaking stress of the ultra-high strength bladder is is 2.76GPa, the thickness of the capsule 1mm, and the diameter of the bag pile It is tentatively set at 1.65m, among which the force diagram during bag grouting is as follows Figure 8 As shown, the mechanical formula is established: , the maximum grouting pressure of the bag pile can be calculated The value is 3.345MPa.

[0051] The height of the bag pile is designed to be 6m, and the density of the grouting material is 2200kg / m 3 , it is found that the limit value of the self-weight stress of the filled bladder is 1.32MPa (without considering the influence of water pressure), so the ultra-high-strength bladder with a thickness of 1mm meets the working pressure requirements, and the safety factor is 2.53.

[0052] 3) Safety verification of bag pile grouting process

[0053] The height of the bag grouting is designed to be 6m, and the density of the lightweight grouting material is 1200kg / m 3 The extreme value of the deadweight stress of the filled bag is 0.72MPa (without considering the influence of water pressure), and the safety factor is 1.92, so the safety of the bag is =1.38MPa, substitute into the formula: , the maximum diameter of the capsule is calculated The tunnel section is reduced from 19.4m2 to 0.2m2 during the grouting process. The water flow velocity will increase from 0.072m / s to 6.94m / s according to the on-site measurement. The water pressure extreme value of the groundwater in the tunnel is obtained. The pressure is 2.8 MPa, and the Venturi formula is as follows:

[0054]

[0055]

[0056] )

[0057] Water flow pressure of bag pile =462kN, which is much smaller than the shear resistance limit of the bag pile and the breaking load of the bag, and can ensure the safety and stability of the bag pile during the pouring process.

[0058] 3. After the bag pile group is formed, it can block water. In order to further improve the water blocking effect, expansion elastomers 12 of different specifications are fed into the tunnel 1 from the feeding hole 7 to between the bag pile group and the heading face 2. Under the suction of the water flow, they accumulate and gradually expand at the bag pile group. Combined with the Midwest 211 (emergency type) polymer water blocking reinforcement material fed from the feeding hole 7, the water gushing volume is finally controlled within the conditions that meet the grouting construction conditions.

[0059] 4) After the bag pile group is formed, the drainage capacity in the tunnel is increased until the water level in the tunnel drops below 0.5m. The local leakage points of the bag pile group are blocked on the side of the bag pile group facing the tunnel entrance. The diversion grouting method can be used for construction until it is completely blocked.

[0060] 5) Construct a water blocking wall 9 in the horizontal section of the tunnel, which is about 20-30m long and as high as the tunnel. The junction between the water blocking wall 9 and the tunnel body must be grouted and sealed tightly to prevent water leakage. Install a drainage pipe 10 1m from the bottom of the water blocking wall and pass it to the front of the heading face.

[0061] In this embodiment, the expansion elastic body is a water blocking material filled in front of the tunnel face. In other embodiments, the water blocking material can be aggregate.

[0062] Embodiment 2 of the tunnel water blocking construction method provided by the present invention:

[0063] The main difference between this embodiment and Example 1 is that in Example 1, the tunnel is pumped after the bag piles are formed, and a water blocking wall is built in the tunnel after the water level in the tunnel drops to a set height. In this embodiment, the amount of water inflow in the tunnel is already small after the bag piles are formed, and a water blocking wall can be built directly. In other embodiments, the water blocking wall can be eliminated and only the bag piles can be used for water blocking.

[0064] Embodiment 3 of the tunnel water blocking construction method provided by the present invention:

[0065] The main difference between this embodiment and Example 1 is that in Example 1, after the bag pile is formed, water blocking materials are put into the tunnel through the feeding hole, and the water blocking materials form water blocking at the bag pile to enhance the water blocking effect. In this embodiment, the feeding hole is eliminated, and water blocking is only performed by relying on the bag pile.

[0066] Embodiment 4 of the tunnel water blocking construction method provided by the present invention:

[0067] The main difference between it and Example 1 is that in Example 1, there are multiple rows of bag piles, and the multiple rows of bag piles are staggered. During construction, a drill rod wrapped with a bag is first placed in the bag pile hole near the middle position to form a bag pile, and then the bag piles are formed in sequence around the formed bag pile. In this embodiment, the bag piles can be formed in sequence along the extension direction of the tunnel. In other embodiments, the number and arrangement of bag piles can be changed. For example, adjacent rows of bag piles are no longer staggered. In other embodiments, only one bag pile can be used for water blocking. In this case, the outer diameter of the bag pile is larger and it contacts the tunnel body for water blocking.

[0068] Embodiment 5 of the tunnel water blocking construction method provided by the present invention:

[0069] The main difference between this embodiment and the first embodiment is that in the first embodiment, the drill bit drills into the bottom plate of the tunnel to form a bottom plate borehole, and the bag pile is inserted into the bottom plate borehole. In this embodiment, when there is only one bag pile, the bag pile is positioned in the tunnel by squeezing and stopping with the side wall of the tunnel body, and no longer needs to be inserted into the bottom plate borehole.

[0070] Although this specification has shown and described a plurality of embodiments of the present invention, it is obvious to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art will think of many changes, modifications and alternatives without departing from the thought and spirit of the present invention. It should be understood that in the process of practicing the present invention, various alternatives to the embodiments of the present invention described herein may be adopted. The attached claims are intended to define the scope of protection of the present invention, and therefore cover the modular composition, equivalent or alternatives within the scope of protection of these claims.

Claims

1. A tunnel water blocking construction method, characterized in that: The following steps are involved: 1) Constructing a bag pile hole connected to the tunnel from the ground downward, where the bag pile hole is located in front of the tunnel face; 2) After the drill is lifted, a bag is wrapped around the outside of the drill rod and lowered into the tunnel through the bag pile hole, slurry is poured into the bag through the drill rod to expand the bag, and after the slurry solidifies, the drill rod is lifted up to form a bag pile for water blocking in the tunnel; The bag pile holes and corresponding bag piles are arranged in plurality, and the bag piles are pressed against each other to form a bag pile group for water blocking; In step 1), when constructing the bag pile hole, the drill bit drills into the tunnel floor to a set depth to form a floor drill hole on the tunnel floor; in step 2), the drill rod wrapped with the bag is lowered into the floor drill hole so that the bottom of the bag pile is inserted into the floor drill hole; Each bag pile hole is arranged in at least two rows along the extension direction of the tunnel, and any two adjacent rows of bag pile holes are staggered in a direction perpendicular to the extension direction of the tunnel; A feeding hole connected to the tunnel is constructed from the ground downwards, wherein the feeding hole is located between the bag pile and the tunnel face; after the bag pile is formed, water blocking materials are fed into the tunnel from the feeding hole, and the bag pile is used to intercept the water blocking materials; After the bag pile is formed, a water blocking wall is constructed on the side of the bag pile close to the hole to block the water gushing.

2. The tunnel water blocking construction method according to claim 1, characterized in that: First, a drill rod wrapped with a bag is lowered into the bag pile hole located in the middle position and slurry is poured in to form a bag pile, and then bag piles are formed in sequence from the inside to the outside around the formed bag pile.

3. The tunnel water blocking construction method according to claim 1, characterized in that: The water blocking material is an elastic expansion body that swells when exposed to water.

4. The tunnel water blocking construction method according to claim 1, characterized in that: Before constructing the water blocking wall, the tunnel is pumped until the water level drops to the set height.

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