Pre-reinforcement arrangement structure for tunnel face of high-ground-stress soft-rock large-deformation tunnel

Abstract

The utility model provides a high ground stress soft rock large deformation tunnel face pre-reinforcement arrangement structure which comprises a concrete blocking layer sprayed on an excavation face of an upper portion section, a plurality of installation holes formed in the upper portion section, glass fiber anchor rods arranged in the installation holes, mortar solidification layers arranged between the glass fiber anchor rods and the hole walls of the installation holes. A glass fiber anchor rod is arranged on the upper section, a downwards-inserted anchor bar pile is arranged at the arch foot position, close to the lower section, of the upper section, the lower end of the anchor bar pile is far away from the tunnel face, and the glass fiber anchor rod is arranged on the upper section, so that the construction cost and the construction difficulty are reduced, and the construction efficiency and the construction safety are improved; the bonding friction effect and the pressure bearing effect with the rock-soil body are improved, pulling force is transmitted to the deep position of the rock-soil body, meanwhile, the effect of a slide-resistant pile is achieved, lateral deformation is resisted, glass fibers and anchor bar piles are combined, displacement of a tunnel face is greatly reduced, the stability of the tunnel face is improved, and excavation safety is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of pre-reinforcement of tunnel construction in water conservancy and hydropower engineering, in particular to a pre-reinforcement arrangement structure for a tunnel face with high ground stress, soft rock and large deformation. Background Art

[0002] For weak surrounding rock, especially the surrounding rock that is easily softened by water, face reinforcement is an important means to ensure smooth excavation. Compared with construction methods such as steps, CD, CRD, and double-side wall pilot tunnels, the above-mentioned pre-reinforcement construction method can well solve the problems of weak tunnel surrounding rock and easy instability of the face, but the construction procedure is complicated, the material waste is serious, and the construction period is slow.

[0003] Most tunnel face collapses start with the destruction of the core rock mass. Traditional front pre-reinforcement measures usually use steel anchors and shotcrete to pre-reinforce the core rock mass in front of the tunnel face under broken and weak surrounding rock geological conditions. However, the cutting of steel will increase the investment in tunnel construction and also reduce the efficiency of tunnel excavation. To solve the above problems, scholars have proposed using grouting free-cutting anchors to pre-reinforce the core rock mass. However, due to the complex construction process of grouting reinforcement and the long time it takes for the slurry to solidify and form a reinforced area, it is not conducive to safe and rapid construction. Utility Model Content

[0004] The purpose of the utility model is to overcome the deficiencies of the above-mentioned prior art and provide a pre-reinforcement arrangement structure for a tunnel face with high ground stress, soft rock and large deformation, which can solve the problems of high cost and slow construction period of the existing tunnel face pre-reinforcement construction method.

[0005] To this end, the utility model adopts the following technical solutions:

[0006] A pre-reinforcement arrangement structure for a tunnel face with high ground stress and large deformation in soft rock, comprising a concrete sealing layer sprayed on the excavation surface of an upper section, a plurality of mounting holes arranged in the upper section, glass fiber anchor rods arranged in the mounting holes, a mortar solidification layer arranged between the glass fiber anchor rods and the hole walls of the mounting holes, and downwardly inserted anchor piles arranged at the arch foot of the upper section close to the lower section, the lower ends of the anchor piles being away from the tunnel face.

[0007] On the basis of adopting the above technical solutions, the present invention can also adopt the following further technical solutions, or use these further technical solutions in combination:

[0008] The anchor pile comprises a grouting pipe, and the grouting pipe is sleeved with a plurality of steel pipe sections, the plurality of steel pipe sections are distributed along the length direction of the grouting pipe, and a plurality of steel bars are fixed on the outer surface of the steel pipe section.

[0009] The outer hoop of the anchor pile is provided with a plurality of steel bar rings, the outer surface of each steel pipe section is provided with the steel bar ring, and the steel bar rings are provided between two adjacent steel pipe sections.

[0010] Anchor holes are respectively arranged at the arch feet on both sides of the upper section, and the two anchor holes located in the same section are in an eight-shaped shape. The anchor piles are arranged in the anchor holes, and a cement mortar layer is arranged between the anchor piles and the hole walls of the anchor holes.

[0011] Several anchor holes are provided in the tunnel excavation direction, and the distance between two adjacent anchor holes in the tunnel excavation direction is 1m.

[0012] A plurality of the fiberglass anchor rods are arranged in the vertical centerline direction of the tunnel, and a plurality of the fiberglass anchor rods are symmetrically distributed on both sides of the vertical centerline. The distance between the fiberglass anchor rods and the inner wall of the tunnel is greater than or equal to 1m, and the distance between two adjacent fiberglass anchor rods is 1m~1.5m.

[0013] The length of the glass fiber anchor rod is 4m-6m, and the length of the glass fiber anchor rod exposed from the tunnel face 1 is 0.2m-0.3m.

[0014] The hole diameter of the anchor hole is greater than or equal to 120 mm, and the hole depth of the anchor hole is 10 cm greater than the length of the anchor pile.

[0015] The angle between the anchor pile and the vertical direction is 30°.

[0016] The distance between two adjacent steel pipe sections is 2m, the length of the steel pipe section is 10cm, and the diameter of the steel bar is 32mm.

[0017] Compared with the prior art, the utility model has the following advantages and beneficial effects: by arranging glass fiber anchor rods with high tensile strength and low shear strength on the upper section, the reinforcement effect on the heading face is achieved by improving the surrounding rock parameters and improving the surrounding rock stress, and it can adapt to the requirements of rapid mechanized construction of large-section tunnels, reduce construction costs and construction difficulties, and improve construction efficiency and construction safety. Anchor piles are arranged on the lower section to increase the bonding friction and pressure bearing effect with the rock and soil body, and transmit the pulling force to the deep part of the rock and soil body. At the same time, it plays the role of anti-slip piles to resist lateral deformation. The glass fiber and anchor piles are combined to greatly reduce the displacement of the heading face, improve the stability of the heading face, and ensure excavation safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a typical cross-sectional schematic diagram of the utility model.

[0019] Figure 2 It is a schematic diagram of the side structure of the tunnel of the present utility model.

[0020] Figure 3 It is a schematic diagram of the cross-sectional structure of the anchor pile of the utility model. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solution of the present invention, the preferred implementation scheme of the present invention is described below in conjunction with specific embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent elements with the same or similar functions. However, it should be understood that the drawings are only used for illustrative purposes and cannot be understood as limitations on the present invention. In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted, and the positional relationship described in the drawings is only used for illustrative purposes and cannot be understood as limitations on the present invention.

[0022] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0023] The utility model provides a pre-reinforcement arrangement structure for a tunnel face with high ground stress and large deformation in soft rock, comprising a concrete sealing layer sprayed on the excavation surface of an upper section 2, a plurality of mounting holes being arranged in the upper section 2, glass fiber anchor rods 4 being arranged in the mounting holes, a mortar solidification layer being arranged between the glass fiber anchor rods 4 and the hole walls of the mounting holes, an anchor pile 5 inserted downwardly being arranged at the arch foot of the upper section 2 close to the lower section 3, and the lower end of the anchor pile 5 being away from the tunnel face 1.

[0024] In this embodiment, the concrete sealing layer adopts CF30 (nano concrete).

[0025] The anchor pile 5 comprises a grouting pipe 7 , and a plurality of steel pipe sections 6 are sleeved on the grouting pipe 7 . The plurality of steel pipe sections 6 are distributed along the length direction of the grouting pipe 7 , and a plurality of steel bars 8 are fixed on the outer surface of the steel pipe sections 6 .

[0026] In this embodiment, the steel pipe section 6 is a 1-inch steel pipe section, and three steel bars 8 are arranged around the circumference of the steel pipe section 6. The steel pipe section 6 is welded to the steel bars 8. The distance between two adjacent steel pipe sections 6 is 2m, the length of the steel pipe section 6 is 10cm, and the diameter of the steel bars 8 is 32mm.

[0027] The outer side of the anchor pile 5 is hooped with a plurality of steel bar rings, the outer surface of each steel pipe section 6 is respectively provided with a steel bar ring, and steel bar rings are respectively provided between two adjacent steel pipe sections 6 .

[0028] Anchor holes are respectively arranged at the arch feet on both sides of the upper section 2. The two anchor holes located in the same section are in an eight-shaped shape. Anchor piles 5 are arranged in the anchor holes. A cement mortar layer 9 is arranged between the anchor piles 5 and the hole wall of the anchor hole.

[0029] In this embodiment, the grouting pipe 7 passes through several steel pipe sections 6 in sequence and reaches the bottom of the anchor hole. The cement mortar layer 9 adopts M25 cement mortar with a mix ratio of cement: river sand: water = 1:1.28:0.45.

[0030] Several anchor holes are provided in the tunnel excavation direction, and the distance between two adjacent anchor holes in the tunnel excavation direction is 1m.

[0031] A plurality of glass fiber anchor rods 4 are arranged in the vertical centerline direction of the tunnel, and a plurality of glass fiber anchor rods 4 are symmetrically distributed on both sides of the vertical centerline. The distance between the glass fiber anchor rods 4 and the inner wall of the tunnel is greater than or equal to 1m, and the distance between two adjacent glass fiber anchor rods 4 is 1m~1.5m.

[0032] The above-mentioned tunnel inner wall is the tunnel excavation outline during the construction process.

[0033] The length of the glass fiber anchor rod 4 is 4m~6m, the length of the glass fiber anchor rod 4 exposed from the tunnel face 1 is 0.2m~0.3m, and the pre-reinforcement overlap length is 2m~3m.

[0034] The hole diameter of the anchor hole is greater than or equal to 120 mm, and the hole depth of the anchor hole is 10 cm greater than the length of the anchor pile 5.

[0035] The angle between the anchor pile 5 and the vertical direction is 30°.

[0036] The implementation steps of the utility model of a high ground stress soft rock large deformation tunnel face pre-reinforcement arrangement structure are as follows:

[0037] Step 1: Divide the high-stress soft rock large-deformation tunnel face 1 into two parts, an upper section 2 and a lower section 3, and excavate them one after another.

[0038] Step 2: During the excavation of the upper section 2, CF30 (nano concrete) is used to seal it in time. After the strength of the sprayed concrete reaches 75%, a three-arm trolley or hand drill is used to make holes. After manual grouting, rods are inserted. After grouting, glass fiber anchor rods 4 are inserted to improve the stability of the face 1. After the concrete is completely solidified, a concrete sealing layer is formed.

[0039] Step 3. After the anchoring of the upper section 2 is completed, drill holes in the rock mass at the arch foot of the upper section 2 to set anchor piles 5. The hole diameter is not less than 120 mm, the hole depth is deepened by 10 cm according to the designed length of the anchor piles 5, the hole spacing is 1 m, and the drilling direction is 30° outward with the vertical direction.

[0040] Step 4: During construction, a hole is drilled in the rock mass, and the grouting pipe 7 and the anchor pile 5 are tied together and inserted into the hole. The grouting pipe 7 is used to grout the entire hole at one time. The grouting slurry uses pure cement slurry or cement mortar with a strength grade not less than M25.

[0041] According to the description and drawings of the utility model, those skilled in the art can easily manufacture or use a high-stress soft rock large-deformation tunnel face pre-reinforcement arrangement structure of the utility model, and can produce the positive effects recorded in the utility model.

[0042] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present utility model and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two mechanisms, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0043] In the description of the present invention, it should be understood that the terms "one end", "the other end", "outside", "inside", "horizontal", "end", "length", "outer end", "left", "right" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the mechanism or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. The terms "first" and "second" are also used only for the simplicity of description, and do not indicate or imply relative importance.

[0044] Furthermore, in practicing the claims of the present invention, those skilled in the art may understand and affect variations to the disclosed embodiments by studying the drawings, disclosure, and appended claims. In addition, in the claims and the specification, words such as "comprises", "comprising", etc. do not exclude other elements or steps, and non-plural nouns do not exclude their plural forms.

[0045] The above is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made according to the present invention are covered by the scope of the claims of the present invention and will not be listed one by one here.

Claims

1. A pre-reinforcement arrangement structure for a tunnel face with high ground stress and large deformation in soft rock, wherein the tunnel face (1) is divided into an upper section (2) and a lower section (3), and is characterized in that: The invention comprises a concrete sealing layer sprayed on the excavation surface of the upper section (2), a plurality of mounting holes are arranged in the upper section (2), glass fiber anchor rods (4) are arranged in the mounting holes, a mortar solidification layer is arranged between the glass fiber anchor rods (4) and the hole walls of the mounting holes, and an anchor pile (5) inserted downward is arranged at the arch foot of the upper section (2) close to the lower section (3), and the lower end of the anchor pile (5) is away from the tunnel face (1).

2. A high-stress soft rock large-deformation tunnel face pre-reinforcement arrangement structure as claimed in claim 1, characterized in that: The anchor pile (5) comprises a grouting pipe (7), the grouting pipe (7) being sleeved with a plurality of steel pipe sections (6), the plurality of steel pipe sections (6) being distributed along the length direction of the grouting pipe (7), and a plurality of steel bars (8) being fixed to the outer surface of the steel pipe section (6).

3. A high-stress soft rock large deformation tunnel face pre-reinforcement arrangement structure as claimed in claim 2, characterized in that: The outer surface of the anchor pile (5) is provided with a plurality of steel bar rings, the outer surface of each steel pipe section (6) is provided with the steel bar ring, and the steel bar rings are provided between two adjacent steel pipe sections (6).

4. The high-stress soft rock large deformation tunnel face pre-reinforcement arrangement structure according to claim 1, characterized in that: Anchor holes are respectively provided at the arch feet on both sides of the upper section (2); the two anchor holes located on the same section are in an eight-shaped shape; the anchor piles (5) are provided in the anchor holes; and a cement mortar layer (9) is provided between the anchor piles (5) and the wall of the anchor hole.

5. A high-stress soft rock large deformation tunnel face pre-reinforcement arrangement structure as claimed in claim 4, characterized in that: Several anchor holes are provided in the tunnel excavation direction, and the distance between two adjacent anchor holes in the tunnel excavation direction is 1m.

6. The high-stress soft rock large deformation tunnel face pre-reinforcement arrangement structure according to claim 1, characterized in that: A plurality of the glass fiber anchor rods (4) are arranged in the vertical centerline direction of the tunnel, and a plurality of the glass fiber anchor rods (4) are symmetrically distributed on both sides of the vertical centerline, the distance between the glass fiber anchor rods (4) and the inner wall of the tunnel is greater than or equal to 1 m, and the distance between two adjacent glass fiber anchor rods (4) is 1 m to 1.5 m.

7. The high-stress soft rock large deformation tunnel face pre-reinforcement arrangement structure according to claim 1, characterized in that: The length of the glass fiber anchor rod (4) is 4m to 6m, and the length of the glass fiber anchor rod (4) exposed from the tunnel face (1) is 0.2m to 0.3m.

8. The high-stress soft rock large deformation tunnel face pre-reinforcement arrangement structure according to claim 4, characterized in that: The diameter of the anchor hole is greater than or equal to 120 mm, and the depth of the anchor hole is 10 cm greater than the length of the anchor pile (5).

9. The high-stress soft rock large deformation tunnel face pre-reinforcement arrangement structure according to claim 1, characterized in that: The angle between the anchor pile (5) and the vertical direction is 30°.

10. The high-stress soft rock large-deformation tunnel face pre-reinforcement arrangement structure according to claim 2, characterized in that: The distance between two adjacent steel pipe sections (6) is 2 m, the length of the steel pipe section (6) is 10 cm, and the diameter of the steel bar (8) is 32 mm.

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