Novel spray anchor structure for soil tunnel

Abstract

The utility model relates to the technical field of tunnel support, in particular to a novel shotcrete anchor structure for a soil tunnel, which solves the problems that the self-bearing capacity of tunnel surrounding rock cannot be utilized and the construction cost is high in the existing primary support structure of the soil tunnel. A novel shotcrete and anchor structure for a soil tunnel comprises a soil surrounding rock, a shotcrete layer is constructed on the excavation surface of the soil surrounding rock, and the novel shotcrete and anchor structure further comprises a plurality of novel anchor rods and a reinforcing mesh. Each novel anchor rod comprises an anchor rod body, an anchor rod base plate and two anchor rod anchor heads; auxiliary limiting grooves are formed in the two sides of the anchor rod base plate; the two anchor rod anchor heads are installed at the two ends of the anchor rod body respectively. One end of each anchor rod anchor head is a conical tip, and a pressing groove is formed in the end, away from the conical tip, of each anchor rod anchor head. Each novel anchor rod obliquely crosses through the cross-shaped grid of the reinforcing mesh and is inserted into the soil surrounding rock, and the anchor rod base plate is arranged between the anchor rod body and the reinforcing mesh.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnel support, in particular to a novel spray anchor structure used for earth tunnels. Background Art

[0002] Steel anchor is a common support tool, which is widely used in tunnel support scenarios. However, the excavation space of earth tunnels is limited. Too long steel anchors are inconvenient to construct in the limited excavation space, so the length of steel anchors used for earth tunnel support is limited. In some earth tunnels, the plastic deformation area of ​​the tunnel surrounding rock is large. If the length of the steel anchor is not enough to pass through the plastic deformation area, the steel anchor as a whole will be in an unstable plastic deformation area. The steel anchor will deform with the tunnel surrounding rock and be in a compressed state. It cannot form a reliable combined structure with shotcrete, and thus loses the effect of supporting the tunnel surrounding rock.

[0003] In view of the problem that the supporting effect of steel anchor rods on earth tunnels is sometimes not significant, technicians currently use a combination structure of steel frame and shotcrete for initial support of earth tunnels, eliminate steel anchor rods, use higher-strength steel frames, and add locking anchor rods. However, this combination structure completely relies on the steel frame and shotcrete to bear the surrounding rock load caused by earth tunnel excavation, and cannot utilize the self-bearing capacity of the tunnel surrounding rock. In addition, as an initial support structure, the higher-strength steel frame has a higher cost. In order to adapt to the high-strength steel frame, the shotcrete also needs to be thickened, so the overall project cost is relatively high.

[0004] Based on this, it is necessary to invent a new type of sprayed anchor structure for earth tunnels to solve the problems existing in the initial support structure of earth tunnels. Utility Model Content

[0005] The utility model provides a novel sprayed anchor structure for earth tunnels to solve the problems that the current earth tunnel initial support structure cannot utilize the self-bearing capacity of the tunnel surrounding rock and the engineering cost is high.

[0006] The utility model is realized by adopting the following technical solutions:

[0007] A new type of shotcrete structure for earth tunnels, comprising earth surrounding rock, a shotcrete layer applied on the excavated surface of the earth surrounding rock, and a plurality of new anchor rods and steel meshes;

[0008] Each new anchor rod comprises an anchor rod body, an anchor rod pad and two anchor rod heads; auxiliary limit grooves are provided on both sides of the anchor rod pad; the two anchor rod heads are respectively installed at the two ends of the anchor rod body; one end of each anchor rod head is a conical tip, and a pressure groove is provided on the end of each anchor rod head away from the conical tip;

[0009] Each new type of anchor rod obliquely crosses the cross grid of the steel mesh and is inserted into the interior of the soil surrounding rock, and the anchor rod pad is padded between the anchor rod body and the steel mesh.

[0010] Furthermore, the anchor rod body is a polymer fiber rod formed by twisting a plurality of polymer fibers into strands.

[0011] Furthermore, each anchor head has a receiving cavity inside, and an anchor plug is arranged in the receiving cavity; an insertion hole is formed at one end of each anchor head away from the conical tip and the anchor plug, and the end of the anchor rod body passes through the insertion hole and enters the receiving cavity.

[0012] Furthermore, the accommodating cavity is a conical cavity, the plug hole is connected with the right tip of the accommodating cavity, and the anchor plug is filled at the right tip of the accommodating cavity; the anchor plug is a rubber plug.

[0013] Furthermore, both ends of each anchor rod body pass through the auxiliary limiting grooves on both sides of the anchor rod pad, and both ends of each anchor rod body are respectively inserted into a pair of grids of the steel mesh that are diagonally distributed.

[0014] The utility model has a reasonable and reliable structural design and has the following beneficial effects compared with the current soil tunnel initial support structure:

[0015] First, the polymer fiber rod is flexible and has high tensile strength. After penetrating the plastic deformation area, it can give full play to the suspension and anchoring functions of the new anchor rod, thereby increasing the stability of the tunnel surrounding rock.

[0016] Secondly, polymer fiber has low cost, high tensile strength, short construction period and low overall project cost. Compared with traditional technology, at the same cost, the new anchor rods can be densely arranged in the tunnel radial direction. The polymer fiber rods play a reinforcing role in the plastic deformation area of ​​the tunnel surrounding rock, forming the loose soil into an overall structure, enhancing the soil arch effect and improving the bearing capacity of the tunnel surrounding rock.

[0017] In addition, polymer fibers can be coiled into rolls, and during construction, the required anchor rod body can be cut out according to actual conditions. This makes it easier to construct longer new anchor rods, thereby enhancing the reinforcement of the tunnel soil and not being restricted by limited excavation space. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the utility model.

[0019] Figure 2 It is a structural schematic diagram of the new anchor rod in the utility model.

[0020] Figure 3 It is a structural schematic diagram of the anchor head of the anchor rod in the utility model.

[0021] Figure 4It is a schematic diagram of the positional relationship between the steel mesh and the novel anchor rod in the utility model.

[0022] Figure 5 It is a structural schematic diagram of the anchor rod pad in the utility model.

[0023] In the figure: 1-soil surrounding rock, 2-sprayed concrete layer, 3-new anchor rod, 31-anchor rod body, 32-anchor rod pad, 321-auxiliary limiting groove, 33-anchor rod head, 331-pressing groove, 332-accommodating cavity, 333-anchor plug, 4-steel mesh. DETAILED DESCRIPTION

[0024] A new type of shotcrete anchor structure for earth tunnels, comprising earth surrounding rock 1, a shotcrete layer 2 is applied on the excavated surface of the earth surrounding rock 1, and also comprising a plurality of new anchor rods 3 and steel meshes 4;

[0025] Each new anchor rod 3 comprises an anchor rod body 31, an anchor rod pad 32 and two anchor rod heads 33; auxiliary limit grooves 321 are provided on both sides of the anchor rod pad 32; the two anchor rod heads 33 are respectively installed at both ends of the anchor rod body 31; one end of each anchor rod head 33 is a conical tip, and a pressure groove 331 is provided on the end of each anchor rod head 33 away from the conical tip;

[0026] Each new anchor rod 3 obliquely crosses the cross grid of the steel mesh 4 and is inserted into the soil surrounding rock 1 , and the anchor rod pad 32 is padded between the anchor rod body 31 and the steel mesh 4 .

[0027] The anchor rod body 31 is a polymer fiber rod formed by twisting a plurality of polymer fibers into strands.

[0028] Each anchor head 33 has a receiving cavity 332 therein, and an anchor plug 333 is provided in the receiving cavity 332; an insertion hole is formed through the end of each anchor head 33 away from the conical tip and the anchor plug 333, and the end of the anchor rod body 31 passes through the insertion hole and enters the receiving cavity 332.

[0029] The accommodating cavity 332 is a conical cavity, the plug hole is connected with the right tip of the accommodating cavity 332, and the anchor plug 333 is filled at the right tip of the accommodating cavity 332; the anchor plug 333 is a rubber plug, which can increase the friction between the anchor plug 333 and the anchor rod body 31.

[0030] Both ends of each anchor rod body 31 pass through the auxiliary limiting grooves 321 on both sides of the anchor rod pad 32, and both ends of each anchor rod body 31 are respectively inserted into a pair of diagonally distributed grids of the steel mesh 4.

[0031] The polymer fiber rod can be coiled into a roll; before excavating the earth tunnel, the anchoring length and fixed length of each anchor rod body 31 are designed according to the characteristics of the tunnel surrounding rock, that is, Figure 2 The long end length and short end length of the anchor rod body 31 are shown; then the required anchor rod body 31 is cut out from the whole roll of polymer fiber rod; for Class V soil tunnel surrounding rock, the long end length of the anchor rod body 31 is 6m~8m, and the short end length of the anchor rod body 31 is not less than 2.5m; for Class IV soil tunnel surrounding rock, the long end length of the anchor rod body 31 is 4m~6m, and the short end length of the anchor rod body 31 is not less than 2m; both ends of each anchor rod body 31 respectively pass through the plug-in hole and enter the corresponding accommodating cavity 332 inside the anchor rod anchor head 33, the anchor rod body 31 is tensioned, and the anchor rod body 31 and the anchor rod anchor head 33 are connected together. Example 1

[0032] After the earth tunnel is excavated, a shotcrete layer 2 is initially sprayed on the excavated surface of the earth surrounding rock 1, and the initial spraying thickness of the shotcrete layer 2 is 2 cm to 3 cm; a steel mesh 4 is laid on the surface of the initially sprayed shotcrete layer 2, and a plurality of new anchor rods 3 are obliquely passed through the cross grid of the steel mesh 4 and inserted into the interior of the earth surrounding rock 1, and the anchor rod pad 32 is padded between the anchor rod body 31 and the steel mesh 4, and the anchor rod pad 32 is padded at the intersection of the cross grid of the steel mesh 4; after the anchor rod body 31 and the anchor rod anchor head 33 are pressed into the earth surrounding rock 1, the shotcrete layer 2 is applied again, and the re-spraying of the shotcrete layer 2 The thickness is 8cm~12cm; thus, a new type of sprayed anchor structure composed of soil surrounding rock 1, sprayed concrete layer 2 and new anchor rod 3 is formed; in this embodiment, the anchor rod body 31 adopts polymer fiber with a diameter of 3mm~6mm; the anchor rod pad 32 adopts a steel pad commonly used in tunnel construction, with a length of not less than 150mm, a width of not less than 150mm, and a thickness of not less than 6mm; the auxiliary limiting groove 321 is a semicircular hole with a diameter of 10mm; the steel mesh 4 adopts conventional plain round steel bars, the diameter of the plain round steel bars is 6mm~8mm, and the grid side length of the steel mesh 4 is 150mm~200mm. Example 2

[0033] After the excavation of the earthen tunnel, a shotcrete layer 2 is initially sprayed on the excavated surface of the earthen surrounding rock 1, and the initial spraying thickness of the shotcrete layer 2 is 2cm~3cm; a steel mesh 4 is laid on the surface of the initially sprayed shotcrete layer 2, and a number of new anchor rods 3 are obliquely crossed through the cross grid of the steel mesh 4 and inserted into the interior of the earthen surrounding rock 1; after the anchor rod body 31 and the anchor rod anchor head 33 are pressed into the earthen surrounding rock 1, a shotcrete layer 2 is applied again, and the re-spraying thickness of the shotcrete layer 2 is 8cm~12cm; thereby forming a new type of sprayed anchor structure composed of the earthen surrounding rock 1, the shotcrete layer 2 and the new anchor rod 3; in this embodiment, the anchor rod body 31 adopts a polymer fiber with a diameter of 6mm~10mm; the steel mesh 4 adopts conventional plain round steel bars, the diameter of the plain round steel bars is not less than 8mm, and the grid side length of the steel mesh 4 is 150mm~250mm; the spacing between the two anchor rod anchor heads 33 of each new anchor rod 3 is not less than 150mm.

[0034] In the process of inserting the new anchor rod 3 into the soil surrounding rock 1, the anchor rod anchor head 33 together with the anchor rod body 31 are pressed into the soil surrounding rock 1 with the help of an external static hydraulic press and a pressure rod: the external pressure rod is pressed against the pressure groove 331, and the pressure rod and the anchor rod anchor head 33 are pressed into the soil surrounding rock 1 by the pressure provided by the external static hydraulic press, and the anchor rod body 31 is connected to the anchor rod anchor head 33, so it also enters the soil surrounding rock 1 together with the anchor rod anchor head 33; finally, the pressure rod is pulled out, and the operation of inserting the new anchor rod 3 into the soil surrounding rock 1 is completed; preferably, the length of each anchor rod body 31 is The insertion direction of the short end is perpendicular to the tangent direction of the corresponding insertion point; the insertion direction of the short end of each anchor rod body 31 is 60°~80° to the tangent direction of the corresponding insertion point; in the soil surrounding rock 1 of the soil tunnel, when the plastic deformation area is deformed, the anchor rod body 31 and the anchor head 33 will be squeezed. At this time, under the squeezing action of the anchor plug 333, the multiple polymer fibers of the anchor rod body 31 will change from a tightly twisted state to a loose state, so that the connection between the anchor rod body 31 and the anchor head 33 is more firmly established.

[0035] In the description of the present invention, it is necessary to understand that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A new type of shotcrete anchor structure for earth tunnels, comprising earth surrounding rock (1), the excavated surface of the earth surrounding rock (1) being provided with a shotcrete layer (2), characterized in that: Also included are a number of new anchor rods (3) and steel meshes (4); Each new anchor rod (3) comprises an anchor rod body (31), an anchor rod pad (32) and two anchor rod heads (33); auxiliary limit grooves (321) are provided on both sides of the anchor rod pad (32); the two anchor rod heads (33) are respectively mounted on both ends of the anchor rod body (31); one end of each anchor rod head (33) is a conical tip, and the end of each anchor rod head (33) away from the conical tip is provided with a pressure groove (331); Each new anchor rod (3) obliquely crosses the cross grid of the steel mesh (4) and is inserted into the soil surrounding rock (1), and the anchor rod pad (32) is padded between the anchor rod body (31) and the steel mesh (4).

2. The novel spray anchor structure for soil tunnels according to claim 1 is characterized in that: The anchor rod body (31) is a polymer fiber rod formed by twisting a plurality of polymer fibers into strands.

3. The new type of spray anchor structure for soil tunnel according to claim 1 is characterized by: Each anchor rod anchor head (33) has an accommodation cavity (332) formed therein, and an anchor plug (333) is arranged in the accommodation cavity (332); an insertion hole is formed through the end of each anchor rod anchor head (33) away from the conical tip and the anchor plug (333), and the end of the anchor rod body (31) passes through the insertion hole and enters the accommodation cavity (332).

4. The novel spray anchor structure for soil tunnels according to claim 3 is characterized in that: The accommodating cavity (332) is a conical cavity, the plug hole is connected to the right tip of the accommodating cavity (332), and the anchor plug (333) is filled at the right tip of the accommodating cavity (332); the anchor plug (333) is a rubber plug.

5. The novel spray anchor structure for soil tunnel according to claim 1 is characterized in that: Both ends of each anchor rod body (31) pass through the auxiliary limiting grooves (321) on both sides of the anchor rod pad (32), and both ends of each anchor rod body (31) are respectively inserted into a pair of diagonally distributed grids of the steel mesh (4).

Images