Water-rich section advance water stop curtain structure and construction method

Abstract

The application provides a water-rich site advanced water stop curtain structure, which comprises a expanded groove formed by expanding the tunnel wall behind the working face and an arch-shaped curtain structure arranged in the expanded groove, the arch-shaped curtain structure comprises two concrete base units arranged at the bottom of the tunnel, an arch-shaped steel unit connected to the two concrete base units, and a grouting unit arranged in the arch-shaped steel unit, the arch-shaped steel unit is open towards the groove bottom of the expanded groove, and a grouting opening for the grouting pipe to extend into is arranged on the arch-shaped steel unit. The application has the effect of solving the problems of high cost, material waste and influence of the formation of the water stop wall on the tunnel construction progress in the prior art.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to an advanced water-stop curtain structure and construction method for water-rich areas. Background Technology

[0002] Currently, the common method for water-stopping tunnels in my country is to implement advanced curtain grouting inside the tunnel. This involves stopping the excavation at the tunnel face and first using concrete to form a vertical or stepped grouting wall that is solidified at the tunnel face to seal and reinforce it. Then, advanced drilling is performed on the grouting wall, and grouting is carried out to stop the water. By setting up this grouting wall at the tunnel face, water seepage outside the tunnel outline can be prevented.

[0003] When using the above-mentioned method for curtain grouting, a large amount of concrete is required. At the same time, breaking through the grout stop wall to excavate the working face will also increase costs and waste concrete. In addition, the formation of the grout stop wall will close the working face, causing delays in the construction period and affecting the construction progress. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides an advanced water-stopping curtain structure and construction method for water-rich areas, which can improve the problems of high cost, material waste and the impact of the formation of the grout-stopping wall on the tunnel construction progress in the existing technology.

[0005] On one hand, according to an embodiment of the present invention, an advanced water-stopping curtain structure for water-rich areas includes an enlarged trench formed by enlarging the tunnel wall behind the tunnel face and an arched curtain structure disposed within the enlarged trench. The arched curtain structure includes two concrete foundation units disposed at the bottom of the tunnel, an arched steel unit connected to the two concrete foundation units, and a grouting unit disposed in the arched steel unit. The arched steel unit has an opening facing the bottom of the enlarged trench and is provided with a grouting port for the grouting pipe to extend into.

[0006] Preferably, the arched steel unit includes multiple U-shaped steels connected in sequence, bolts for connecting two adjacent U-shaped steels, and multiple end plates sealing two openings along the length of the U-shaped steels. The U-shaped steels face the bottom opening of the excavated trench, and two of the U-shaped steels are connected to the concrete foundation unit. The end plates are provided with grouting ports for grouting pipes to extend into, and the grouting unit is formed within the multiple U-shaped steels.

[0007] Preferably, the concrete foundation unit includes a concrete foundation section and anchor bolts embedded in the concrete foundation section, and the anchor bolts are connected to the arched steel unit.

[0008] Preferably, it also includes a steel frame foundation supported at the bottom of the tunnel, the steel frame foundation being supported at both ends of the arched steel unit along the tunnel extension direction, and the steel frame foundation being connected to the initial support arch structure used to support the tunnel wall.

[0009] On the other hand, according to embodiments of the present invention, a construction method for an advanced water-stop curtain structure in water-rich areas is also provided, which includes the following steps:

[0010] S1. Tunnel cross-section widening: The tunnel wall behind the working face and supported by the initial arch structure is widened to form a widening trench, and the loose slag is removed and the foundation on both sides is compacted.

[0011] S2. Foundation construction: Two concrete foundation units are poured and formed near the bottom of the tunnel at the widened excavation opening;

[0012] S3. Construction of arched steel units: Arched steel units are erected on the concrete foundation units;

[0013] S4. Grouting: Casting and forming grouting units within arched steel units;

[0014] S5. Reinforcement and Cyclic Construction: The arch-shaped steel units are installed inside the tunnel for support. Then, the tunnel face is excavated and advanced. During the excavation process, the initial arch structure is supported. When the excavation reaches a certain distance, the next water-stop curtain structure is constructed. The construction is carried out in a cyclical manner until the water-rich rock layer is crossed.

[0015] Preferably, the depth of the trench in step S1 is 60cm.

[0016] Preferably, when pouring the concrete foundation unit in step S2, the concrete foundation section is poured first, and anchor bolts are pre-embedded in the concrete foundation section. The concrete foundation section is 70cm long, 60cm wide, and 30cm thick.

[0017] Preferably, in step S3, when erecting the arched steel unit, multiple U-shaped steels are connected to each other by bolts to form an arched structure to fill the excavated trench opening. The U-shaped steels face the bottom of the trench opening, and two of the U-shaped steels are connected to the concrete foundation unit to form an arched structure. End plates are welded to both sides of the length direction of the U-shaped steels, and grouting ports are opened on the end plates.

[0018] Preferably, in step S4, the grouting material is an ultrafine cement-water glass dual grout, with the volume ratio of ultrafine cement to water glass being 1:1 to 1:0.8, the water-cement ratio being 2:1, the water glass concentration being 1.38 g / cm3, and the original solution concentration being 35Be'.

[0019] Preferably, the interval between two adjacent water-stop curtain structures in step S5 is 5m.

[0020] In summary, the present invention has at least one of the following beneficial technical effects:

[0021] 1. By widening the tunnel face behind the tunnel face to form an enlarged trench, and setting an arched curtain structure at the trench, the arched curtain structure acts as a barrier to prevent water seepage down the tunnel profile. The arched curtain structure includes a concrete foundation unit, an arched steel section unit, and a grouting unit. The amount of grout required for the concrete foundation unit and grouting unit is much less than that required for the grout-stopping wall in the prior art, thus reducing costs. Moreover, the arched curtain structure of this invention does not need to be demolished and does not affect the continuous advancement of the tunnel face. That is, the amount of concrete consumed by the grout-stopping wall used in the prior art is much greater than the amount of backfilling work of this invention. At the same time, after the water-stopping curtain is constructed, the grout-stopping wall still needs to be excavated, consuming a lot of costs, and this part of the concrete also loses its function, resulting in concrete waste. This invention improves the problems of high cost and material waste in the formation and subsequent excavation of the grout-stopping wall in the prior art, as well as the impact of the grout-stopping wall formation on the tunnel construction progress. In addition, the backfill concrete of this invention can also control tunnel deformation, reduce the amount of deformation of the tunnel profile, and does not cause concrete waste, resulting in high economic benefits.

[0022] 2. The grouting material used in the grouting unit is ultrafine cement-water glass double-liquid grout, which has good permeability and injectability, facilitates grout diffusion, and has a better water-stopping effect. It solves the shortcomings of single-liquid cement grout in water-rich areas, such as long setting time and difficulty in control, and low stone formation rate under dynamic water conditions. It improves the effect of cement grouting, expands the range of cement grouting, and achieves the purpose of rapid water-stopping.

[0023] 3. Using an enlarged excavation face as the working face for grouting pipe construction, with each cycle interval and overlap of 5m, allows the tunnel to be constructed without interruption under the protection of the water-stop curtain. This has a minimal impact on the tunnel construction period, avoids the work stoppage caused by the construction of the water-stop curtain, and saves project costs. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a first partial cross-sectional structure according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of a second partial cross-sectional structure according to an embodiment of the present invention;

[0026] Figure 3 This is a partial structural schematic diagram of an embodiment of the present invention;

[0027] Figure 4 This is a construction step diagram of the present invention.

[0028] In the above attached figures: 1. Working face; 2. Initial support arch structure; 3. Widened trench opening; 4. Concrete foundation unit; 41. Concrete foundation section; 42. Anchor bolts; 5. Arch-shaped steel unit; 51. U-shaped steel; 52. Bolts; 53. End plate; 531. Grouting port; 6. Grouting unit; 7. Steel frame foundation. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-4 The present invention will be further described below.

[0030] Reference Figures 1 to 3 On one hand, this invention proposes an advanced water-stopping curtain structure for water-rich areas, including an enlarged excavation trench 3 and an arched curtain structure set within the enlarged excavation trench 3. The enlarged excavation trench 3 is an excavation formed at a location where an initial support arch structure 2 has already been formed within a range of 2-5m behind the tunnel face 1. In this invention embodiment, the depth of the enlarged excavation trench 3 along the tunnel outline (radial) is 60cm. After the enlargement, the loose slag is removed and the foundations on both sides are compacted. That is, after the enlargement, the trench surface of the enlarged excavation trench 3 becomes the tunnel wall, which is also the outline surface of the tunnel face 1.

[0031] The arched curtain structure includes two concrete foundation units 4, one arched steel unit 5, and a grouting unit 6. The two concrete foundation units 4 are located at the bottom of the tunnel and include a concrete foundation section 41 and anchor bolts 42. The concrete foundation section 41 is poured into the compacted bottom of the tunnel. In this embodiment of the invention, the concrete foundation section 41 is a concrete foundation with a length of 70cm, a width of 60cm, and a thickness of 30cm. Anchor bolts 42 are pre-embedded during the pouring process.

[0032] The arched steel unit 5 is simultaneously connected to two concrete foundation units 4. It includes multiple U-shaped steel sections 51, multiple bolts 52, and multiple end plates 53. The U-shaped steel sections 51 open towards the bottom of the excavated trench 3, and multiple U-shaped steel sections 51 are sequentially spliced ​​together by bolts 52. Two of the U-shaped steel sections 51 are connected to anchor bolts 42. The bottom end of the U-shaped steel section 51 has an adaptive curvature that changes with the excavated trench 3. Along the tunnel extension direction, the end plates 53 are welded to both ends of the U-shaped steel sections 51, and the end plates 53 have grouting ports 531 for grouting pipes to extend into, forming a grouting unit 6.

[0033] In this embodiment of the invention, the grouting unit 6 uses an ultrafine cement-water glass dual grout, with a volume ratio of ultrafine cement to water glass of 1:1 to 1:0.8, a water-cement ratio of 2:1, a water glass concentration of 1.38 g / cm³, and a stock solution concentration of 35 Be'. The grouting unit 6 formed by grouting can effectively block water seepage below the tunnel outline. Compared to the existing technology that uses the tunnel face 1 to block seepage, this barrier structure not only blocks water but also allows space for excavation of the tunnel face 1. This improves upon the existing technology's problems of high costs and material waste associated with the formation of the grout-stopping wall and subsequent excavation, as well as the impact of the grout-stopping wall formation on tunnel construction progress. Simultaneously, the arched curtain structure can control tunnel deformation, reduce the amount of deformation within the tunnel outline, provide support, and avoid material waste.

[0034] In this embodiment of the invention, after excavating and advancing the tunnel face to 1 to 5 meters, the outer opening of the widened trench 3 and the setting of the arched curtain structure can be carried out again, and so on, until the water-rich section is passed. This allows the tunnel to be constructed without interruption under the protection of the water-stop curtain structure, minimizing the impact on the tunnel construction period and avoiding work stoppages caused by the construction of the water-stop curtain, thus saving project costs. Of course, before advancing the tunnel face 1, the tunnel advancement section needs to be grouted using a drilling rig to enhance the stability of the tunnel's directional structure.

[0035] Furthermore, in this embodiment of the invention, in order to enhance the supporting effect on the arched curtain structure, during the advancement work of the tunnel face 1, a steel frame foundation 7 can be set in the tunnel. The steel frame foundation 7 is supported at both ends of the arched steel unit 5 along the tunnel extension direction, and the steel frame foundation 7 is connected to the initial support arch structure 2 used to support the tunnel wall, thereby enhancing stability.

[0036] Reference Figure 4 On the other hand, this invention also proposes a construction method for an advanced water-stop curtain structure in water-rich areas, which includes the following steps:

[0037] S1. Tunnel cross-section widening: The tunnel wall behind the working face 1 and supported by the initial support arch structure 2 is widened to form a widening trench 3 with a depth of 60cm. After removing loose slag, the foundations on both sides are compacted.

[0038] S2. Foundation construction: Two concrete foundation units 4 are poured and formed at the bottom of the tunnel near the widened excavation opening 3;

[0039] During the pouring process, a concrete foundation section 41 with a length of 70cm, a width of 60cm, and a thickness of 30cm is first poured, and anchor bolts 42 are pre-embedded in the concrete foundation section 41.

[0040] S3. Construction of arched steel unit: Arched steel unit 5 is erected on concrete foundation unit 4;

[0041] During erection, multiple U-shaped steels 51 are connected to each other by bolts 52 to form an arch structure to fill the widened trench 3. The U-shaped steels 51 face the bottom opening of the widened trench 3, and two of the U-shaped steels 51 are connected to anchor bolts 42 to form an arch structure. End plates 53 are welded to both sides of the length direction of the U-shaped steels 51, and the end plates 53 are provided with grouting ports 531.

[0042] S4. Grouting: Grouting unit 6 is formed by pouring grouting into arched steel unit 5 through grouting port 531;

[0043] During the grouting process, the material used is ultrafine cement-water glass dual grout, with an ultrafine cement to water glass volume ratio of 1:1 to 1:0.8, a water-cement ratio of 2:1, a water glass concentration of 1.38 g / cm3, and a stock solution concentration of 35 Be', in order to facilitate grout diffusion and form a better water-stopping effect.

[0044] S5. Reinforcement and Cyclic Construction: The stability is enhanced by setting up a steel frame foundation 7 in the tunnel to support the arched steel unit 5; then the tunnel face 1 is excavated and advanced. During the excavation process, the initial support arch structure 2 is supported, and the next water-stop curtain structure is constructed when the excavation reaches a certain distance (5 meters in this embodiment of the invention). The construction is carried out in a cyclical manner until the water-rich rock layer is crossed.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A pre-sealing curtain structure for water-rich areas, characterized in that: The structure includes an enlarged trench (3) formed by enlarging the tunnel wall behind the tunnel face (1) and an arched curtain structure set within the enlarged trench (3). The arched curtain structure includes two concrete foundation units (4) set at the bottom of the tunnel, an arched steel unit (5) connected to the two concrete foundation units (4), and a grouting unit (6) set within the arched steel unit (5). The arched steel unit (5) opens towards the bottom of the enlarged trench (3) and has a grouting port (531) for the grouting pipe to extend into. The shaped steel unit (5) includes multiple U-shaped steels (51) connected in sequence, bolts (52) for connecting two adjacent U-shaped steels (51), and multiple end plates (53) sealing two openings in the length direction of the U-shaped steels (51). The U-shaped steels (51) face the bottom opening of the excavated trench (3), and two of the U-shaped steels (51) are connected to the concrete foundation unit (4). The end plates (53) are provided with grouting ports (531) for grouting pipes to extend into, and the grouting unit (6) is formed inside the multiple U-shaped steels (51).

2. The advanced water-stopping curtain structure for water-rich areas according to claim 1, characterized in that: The concrete foundation unit (4) includes a concrete foundation section (41) and anchor bolts (42) embedded in the concrete foundation section (41). The anchor bolts (42) are connected to the arched steel unit (5).

3. The advanced water-stopping curtain structure for water-rich areas according to claim 1, characterized in that: It also includes a steel frame foundation (7) supported at the bottom of the tunnel, the steel frame foundation (7) being supported at both ends of the arched steel unit (5) along the tunnel extension direction, and the steel frame foundation (7) being connected to the initial support arch structure (2) used to support the tunnel wall.

4. A construction method for an advanced water-stop curtain structure in a water-rich area according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Tunnel cross-section expansion: The tunnel wall behind the working face (1) and supported by the initial support arch structure (2) is expanded to form an expansion trench (3), and the loose slag is removed and the foundation on both sides is compacted. S2, Foundation construction: Two concrete foundation units (4) are poured and formed near the bottom of the tunnel at the widened trench (3); S3. Construction of arched steel unit: Arched steel unit (5) is erected on the concrete foundation unit (4); S4. Grouting: Cast the grouting unit (6) inside the arched steel unit (5); S5. Reinforcement and cyclic construction: Set up arch steel units (5) for support in the tunnel, then excavate and advance the tunnel face (1). During the excavation process, support the initial arch structure (2), and when the excavation reaches a certain distance, construct the next water-stop curtain structure. Continue the cyclic construction until the water-rich rock layer is crossed.

5. The construction method of an advanced water-stop curtain structure in a water-rich area according to claim 4, characterized in that: In step S1, the depth of the widened trench (3) is 60cm.

6. The construction method of an advanced water-stop curtain structure in a water-rich area according to claim 4, characterized in that: When pouring the concrete foundation unit (4) in step S2, first pour the shaped concrete foundation section (41) and pre-embed anchor bolts (42) in the concrete foundation section (41). The concrete foundation section (41) is 70cm long, 60cm wide and 30cm thick.

7. The construction method of an advanced water-stop curtain structure in a water-rich area according to claim 4, characterized in that: When erecting the arched steel unit (5) in step S3, multiple U-shaped steels (51) are connected to each other by bolts (52) to form an arched structure to fill the excavated trench (3). The U-shaped steels (51) face the bottom of the excavated trench (3), and two of the U-shaped steels (51) are connected to the concrete foundation unit (4) to form an arched structure. End plates (53) are welded on both sides of the length direction of the U-shaped steels (51), and grouting ports (531) are opened on the end plates (53).

8. The construction method of an advanced water-stop curtain structure in a water-rich area according to claim 4, characterized in that: In step S4, the grouting material is an ultrafine cement-water glass dual grout with a volume ratio of ultrafine cement to water glass of 1:1 to 1:0.8, a water-cement ratio of 2:1, a water glass concentration of 1.38 g / cm3, and a stock solution concentration of 35Be'.

9. The construction method of an advanced water-stop curtain structure in a water-rich area according to claim 4, characterized in that: In step S5, the interval between two adjacent water-stop curtain structures is 5m.

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