Protective devices for tunnel steel arch joints and methods for protecting tunnel initial support steel arch joints.

Abstract

This invention provides a protective device for tunnel steel arch joints and a method for protecting the joints of tunnel initial support steel arch joints. The protective device includes a flexible protective cover, two side molds, and an end mold. The two side molds and the end mold, which abut against each other in sequence, provide sufficient support for the flexible protective cover from all directions, allowing it to maintain its shape against concrete and ensuring sufficient operating space after dismantling. After the protective device is installed, the flexible protective cover, the two side molds, and the end mold wrap around the joint from the outside and above. The protection method includes prying open the side and inserting the steel frame into the steel frame passage position while simultaneously placing the joint in the joint position; connecting the module including the side molds and the end mold to the flexible protective cover; and performing the initial support shotcrete operation. This invention is quick and easy to implement, allows for easy demolding, provides ample space for steel arch joint connection, improves the quality of steel arch joint connection, and ensures the overall installation quality and load-bearing structure of the tunnel initial support steel arch.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, specifically to a tunnel steel arch joint protection device and a method for protecting the joints of tunnel initial support steel arches used in tunnel initial support construction. Background Technology

[0002] During tunnel construction, the initial support method varies depending on the surrounding rock conditions. When the surrounding rock conditions are poor, steel arch frames are mostly used for reinforced support.

[0003] The steel arch frame is divided into multiple connected sections. During the step construction process, the connection between the joints of the two steel arch frames is involved when the steps are transitioned. This includes the problem of how to avoid the shotcrete covering the operating space and causing the bolts at the joint connection plate to be unable to be installed.

[0004] There are two existing solutions to the problem of shotcrete covering the connecting plate.

[0005] One method involves applying shotcrete along with the connecting plate without obstruction, followed by manual removal. This method suffers from drawbacks such as high removal difficulty, large workload, poor removal results, and continuous high-altitude work.

[0006] Another method involves burying the slag under a connecting plate before applying shotcrete, and then promptly cleaning up the buried slag. Because the slag is tightly bonded to the concrete, it also requires high-altitude work to remove and clean it, presenting a similarly tedious construction problem. Furthermore, the slag must be thoroughly cleaned to avoid leaving any residue that could affect the overall initial support quality, thus increasing the workload. Summary of the Invention

[0007] The primary objective of this invention is to provide a tunnel steel arch joint protection device that effectively protects the joint and is easy to assemble and disassemble. This protection device eliminates the need for chiseling work and avoids prolonged high-altitude operations. After removing the protection device, the joint is fully exposed, which is beneficial to the quality of steel frame connection.

[0008] The second objective of this invention is to provide a method for protecting tunnel steel arch joints using the invented tunnel steel arch joint protection device.

[0009] The tunnel steel arch joint protection device provided by the first objective of this invention includes a flexible protective cover, two side molds, and an end mold. The flexible protective cover has a joint location and includes a first protective part and a second protective part connected to each other. The first protective part blocks the joint location from a first direction, and the second protective part blocks the joint location from a first side in a second direction. The first protective part has a steel frame through-hole, which communicates with the joint location along the first direction. In the second direction, the first protective part includes an end portion away from the second protective part. The first protective part has a break, which communicates with the steel frame through-hole and the end portion along the second direction. In the third direction, the first protective part forms two side portions on opposite sides of the break, and the side portions have a first connecting structure arranged along the second direction. The side molds are provided with a second connecting structure and a third connecting structure on opposite sides respectively; the end mold is provided with a fourth connecting structure, which is arranged along the first direction and in the third direction, the end molds are provided with a fourth connecting structure on opposite sides respectively; the two side molds are respectively connected to the two sides, the first connecting structure cooperates with the second connecting structure, the two side molds respectively block the joint position from opposite sides in the third direction, and the side molds support the side from the first direction and / or the second direction; both side molds are connected to the end mold, the third connecting structure cooperates with the fourth connecting structure, the end mold blocks the joint position from the second side in the second direction, and the end mold restricts the side mold in the second direction and / or the third direction; the first direction is perpendicular to the second direction, the second direction is perpendicular to the third direction, and the third direction is perpendicular to the first direction.

[0010] As can be seen from the above scheme, the installation and removal of the tunnel steel arch joint protection device are based on the elastic deformation capability of the flexible protective cover. The two side molds and the end molds that abut against each other in sequence can provide sufficient support for the flexible protective cover from multiple directions, allowing it to maintain its shape to resist the internal forces of the concrete, and also ensuring sufficient operating space after removal. After the tunnel steel arch joint protection device is installed, the flexible protective cover, the two side molds, and the end molds wrap around the joint from the outside and above, effectively preventing concrete from seeping in. Since the flexible protective cover is close to the surrounding rock of the tunnel and the end molds face the tunnel, when removing the device, it is only necessary to slightly pull out the end molds to release the support and abutment relationship between the end molds, side molds, flexible protective cover, and concrete. Then, the flexible protective cover can be easily removed by utilizing its elastic deformation. Therefore, this invention is easy to install and fix. After the initial support shotcrete is completed, it can be easily demolded from the concrete, providing ample operating space for the joint installation of the steel arch frame. It also improves the joint quality of the steel arch frame to a certain extent, ensuring the overall installation quality and stress structure of the tunnel's initial support steel arch frame. The on-site implementation and application effects are significant, and it has high economic benefits.

[0011] A further embodiment is that a first inclined surface is provided on the side, and a second inclined surface is provided on the side mold. Both the first and second inclined surfaces are inclinedly arranged between the first and second directions; the first and second inclined surfaces abut against each other.

[0012] As can be seen above, the first and second inclined surfaces form a wedge-shaped fit. After the shotcrete is applied, the force of the concrete increases the contact between the two inclined surfaces, resulting in a stable mutual support effect between the flexible protective cover and the side formwork in both the first and second directions. This further maintains the shape of the flexible protective cover. Furthermore, since the steel arch frame is located at a high altitude and has a large entrance, this design has a certain anti-foolproof effect, making it easier for workers to install the side formwork and reducing the difficulty of installation.

[0013] A further embodiment includes a first end face on the side and a third end face on the second protective part. Both the first and third end faces face the second direction. The first end face, the first inclined surface, and the third end face are bent and connected in sequence. A first connecting structure is provided on the first end face. The side mold has a second end face and a fourth end face. Both the second and fourth end faces face the second direction. The second end face, the second inclined surface, and the fourth end face are bent and connected in sequence. A second connecting structure is provided on the second end face. The first end face abuts against the second end face, and the third end face abuts against the fourth end face.

[0014] As can be seen from the above, this configuration facilitates a tight fit between the side mold and both the first and second protective parts. Furthermore, the end face along the second direction facilitates the installation of the first and second connecting structures. The linear assembly method makes it easier for construction workers to perform high-altitude operations, reducing the difficulty of operation.

[0015] A further design involves providing a third inclined surface on the side mold and a fourth inclined surface on the end mold, with both the third and fourth inclined surfaces positioned at an angle between the second and third directions. Along the second direction and from the first side to the second side, the distance between the third inclined surfaces of the two side molds gradually increases. The third inclined surface abuts against the fourth inclined surface.

[0016] As can be seen above, the third and fourth inclined surfaces form a wedge-shaped fit. After the shotcrete is applied, the two inclined surfaces effectively abut against each other under the force of the concrete. The side formwork and the concrete are stably supported in the third direction. At the same time, the end formwork, the side formwork and the flexible protective cover support each other in sequence, thus further maintaining the shape of the flexible protective cover.

[0017] A further proposed solution is that, in the third direction, the side mold has an outer side surface at the back-to-back joint position; the outer side surface is a fifth inclined surface, which is inclinedly set between the second direction and the third direction; along the second direction and along the direction from the first side to the second side, the distance between the fifth inclined surfaces of the two side molds gradually increases.

[0018] As can be seen from the above, when the shotcrete is completed, the fifth inclined surface acts as a wedge surface to cooperate with the concrete. Firstly, this setting further facilitates the support of the side formwork for the flexible protective cover. Secondly, the fifth inclined surface causes the concrete to expand outward at the entrance of the space. After slightly loosening the end formwork to release the support for the side formwork, the contact between the fifth inclined surface and the concrete surface is completely released. Moreover, as the side formwork is removed, the gap between the side formwork and the concrete gradually increases. Therefore, this setting makes the removal of the side formwork easier.

[0019] A further proposed solution is that the third inclined plane forms a first angle with the straight line, and the fifth inclined plane forms a second angle with the straight line, the second angle being smaller than the first angle; the straight line extends along a second direction and along the direction from the first side to the second side.

[0020] As can be seen from the above, this setting can further enhance the support effect of the end mold as a wedge-shaped part on the side mold.

[0021] A further option is that the flexible protective cover has an outer surface facing away from the joint position, the outer surface being arc-shaped, and the outer surface extending between the first protective part and the second protective part.

[0022] As can be seen from the above, this design reduces the number of sharp edges on the outer surface of the flexible protective cover, which facilitates the separation of the flexible protective cover from the concrete after deformation, thus making the removal of the flexible protective cover easier.

[0023] A further embodiment includes a spring tie rod bolt in the tunnel steel arch joint protection device. The spring tie rod bolt comprises a bolt, a retaining ring, and a spring. The bolt includes a sequentially connected optical axis section and a threaded section. The spring is fitted onto the optical axis section, with its first end closer to the threaded section than its second end, and the first end is fixedly connected to the optical axis section. The retaining ring is slidably fitted onto the optical axis section and is fixedly connected to its second end. A third connection structure includes a first mating hole, comprising a sequentially connected first hole section and a threaded hole section, with the inner diameter of the first hole section being larger than that of the threaded hole section. A fourth connection structure includes a second mating hole, comprising a second hole section and a third hole section, with the inner diameter of the second hole section being smaller than that of the third hole section, forming a step between the second and third hole sections. The spring tie rod bolt passes sequentially through the second and first mating holes, with the threaded section mating with the threaded hole section. The spring is located within the first and second hole sections, and the retaining ring is located within the third hole section, with the retaining ring abutting against the step in the axial direction of the second mating hole.

[0024] As can be seen from the above, when using spring tie rod bolts to connect the end mold and the side mold, pulling the end mold outward will cause it to move under the action of the spring tie rod bolts, while the side mold remains stationary. This releases the contact between the third and fourth inclined surfaces, and simultaneously weakens the contact between the fifth inclined surface of the side mold and the concrete. At this point, the side mold is easier to remove, while the end mold and side mold remain connected. Once the side mold loosens from the concrete, both the end mold and side mold can be removed together. Therefore, this design allows for the simultaneous removal of multiple components in the protective device, significantly reducing operational steps and difficulty, and also lowering the risk of safety accidents caused by components falling from heights.

[0025] The second objective of this invention provides a method for protecting the joint of a tunnel initial support steel arch frame. The tunnel initial support steel arch frame includes a steel frame and a joint, with the joint connected to the extended end of the steel frame. The protection method employs the aforementioned tunnel steel arch frame joint protection device. The protection method includes: bending at least one side to enlarge the fracture; inserting the steel frame through the fracture into the steel frame passage position, while simultaneously inserting the joint into the joint position; connecting a module including side molds and end molds to a flexible protective cover; and performing initial support shotcrete operation.

[0026] A further proposed solution, after the initial shotcrete operation, includes: removing the end formwork from the side formwork; removing the module from the flexible protective cover; and removing the flexible protective cover from the steel frame.

[0027] As can be seen from the above scheme, the protection method of the present invention utilizes the tunnel steel arch joint protection device. The tunnel steel arch joint protection device is easy to install and fix. After the initial support shotcrete is completed, it can easily be demolded from the concrete, providing sufficient operating space for the docking installation of the steel arch joint. It also improves the docking quality of the steel arch to a certain extent, ensuring the overall installation quality and stress structure of the tunnel initial support steel arch. The on-site implementation and application effects are significant, and it has high economic benefits. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view of an embodiment of the tunnel steel arch joint protection device of the present invention in a third-party direction.

[0029] Figure 2 This is a cross-sectional view of an embodiment of the tunnel steel arch joint protection device of the present invention in the first direction.

[0030] Figure 3 This is a structural diagram of the flexible protective cover in the third-party direction in an embodiment of the tunnel steel arch joint protection device of the present invention.

[0031] Figure 4 This is a structural diagram of the flexible protective cover in the first direction in an embodiment of the tunnel steel arch joint protection device of the present invention.

[0032] Figure 5 This is a structural diagram of the side mold in the third-party direction in an embodiment of the tunnel steel arch joint protection device of the present invention.

[0033] Figure 6 This is a structural diagram of the side mold in the first direction in an embodiment of the tunnel steel arch joint protection device of the present invention.

[0034] Figure 7 This is a structural diagram of the end mold in the first direction in an embodiment of the tunnel steel arch joint protection device of the present invention.

[0035] Figure 8 This is a structural diagram of the spring tie rod bolt in an embodiment of the tunnel steel arch joint protection device of the present invention.

[0036] Figure 9 for Figure 1 Enlarged view of point A in the middle.

[0037] Figure 10 This is a first state diagram in the third-party direction of an embodiment of the protection method for the joint of the initial support steel arch frame in tunnel according to the present invention.

[0038] Figure 11 This is a first state diagram in the first direction of an embodiment of the protection method for the joint of the initial support steel arch frame in tunnel according to the present invention.

[0039] Figure 12 This is a second state diagram in the first direction of an embodiment of the protection method for the joint of the tunnel initial support steel arch frame of the present invention.

[0040] Figure 13 This is a second state diagram in the third-party direction of an embodiment of the protection method for the joint of the initial support steel arch frame in tunnel according to the present invention.

[0041] Figure 14 This is a third state diagram in the first direction of an embodiment of the protection method for the joint of the tunnel initial support steel arch frame of the present invention.

[0042] Figure 15 This is a fourth state diagram in the third-party direction of an embodiment of the protection method for the joint of the initial support steel arch frame of the tunnel according to the present invention.

[0043] Figure 16 This is a fifth state diagram in the third-party direction, illustrating an embodiment of the protection method for the joint of the initial support steel arch frame in tunnel according to the present invention. Detailed Implementation

[0044] Tunnel steel arch joint protection device

[0045] A unified spatial rectangular coordinate system is established in all the accompanying drawings. In this coordinate system, the z-axis direction is the first direction of the present invention, the x-axis direction is the second direction of the present invention, and the y-axis direction is the third direction of the present invention. The z-axis direction is vertical, while both the x-axis and y-axis directions are horizontal. (See also...) Figure 10 The negative x-axis direction is towards the surrounding rock 91.

[0046] See Figure 1 , Figure 2 , Figure 10 and Figure 11 The tunnel steel arch joint protection device of the present invention is used in the initial support construction stage of tunnels to shield and protect the joint 92 at the bottom of the steel arch during shotcrete application. This embodiment includes a flexible protective cover 1, two side molds 2, an end mold 3, spring tie rod bolts 4, and tension spring screws 5. The joint 92 at the bottom of the steel arch includes a steel frame 921 and a connecting plate 922 connected to the extended end of the steel frame 921. The connecting plate 922 is the joint in this embodiment.

[0047] Combined Figure 3 and Figure 4 The flexible protective cover 1 is integrally molded from flexible rubber and consists of a first protective part 11 and a second protective part 12 that are interconnected. The flexible protective cover 1 is provided with a joint position 100 for accommodating the connecting plate 922. The first protective part 11 blocks the joint position 100 from the z-axis direction, and the second protective part 12 blocks the joint position 100 from the first side in the x-axis direction.

[0048] See Figure 4 The first protective part 11 is provided with a steel frame through-hole 101, which communicates with the joint position 100 along the z-axis. In the x-axis direction, the first protective part 11 includes an end 119 away from the second protective part 12. The first protective part 11 is provided with a break 102, through which the steel frame through-hole 101 communicates with the end 119 along the x-axis. The steel frame through-hole 101 allows the steel frame 921 to pass through.

[0049] In the y-axis direction, the first protective part 11 forms two side parts 111 on opposite sides of the break 102. Since the flexible protective cover 1 is made of rubber, bending one or both side parts 111 can enlarge the break 102, allowing the steel frame 921 to enter the steel frame passage position 101 from the end 119 through the break 102.

[0050] See Figure 3The flexible protective cover 1 has an outer surface 144 facing away from the connector position 100. The outer surface 144 is arc-shaped and extends between the first protective portion 11 and the second protective portion 12. On the side opposite to the outer surface 144, the flexible protective cover 1 has a first end face 142, a first inclined surface 141, and a third end face 143 that are sequentially bent and connected. The first end face 142 and the third end face 143 are both oriented towards the positive x-axis. The first inclined surface 141 is inclined between the z-axis and the x-axis. The first end face 142 and the first inclined surface 141 are located on the side portion 111, while the third end face 143 is located on the second protective portion 12. In addition, the side portion 111 has a positioning hole 13 opened along the x-axis direction on the first end face 142. The positioning hole 13 is the first connection structure of the present invention.

[0051] Combined Figure 5 and Figure 6 ,like Figure 5 As shown, the side mold 2 is made of metal or other rigid materials such as plastic. On the side facing the negative x-axis, the side mold 2 has a second end face 242, a second inclined surface 241, and a fourth end face 243 that are sequentially bent and connected. The second end face 242 and the fourth end face 243 both face the negative x-axis. The first and second inclined surfaces 241 are inclined between the z-axis and x-axis directions. In the x-axis direction, the side mold 2 has a positioning pin 23 and a first mating hole 25 on opposite sides. The positioning pin 23 and the first mating hole 25 are the second and third connection structures of the present invention, respectively. The positioning pin 23 extends from the second end face 242 along the negative x-axis. (See also...) Figure 6 The first mating hole 25 is opened on a first surface 244 facing the positive x-axis on the side mold 2 and extends along the x-axis direction. The first mating hole 25 includes a first hole section 251 and a screw hole section 252 connected in sequence. The inner diameter of the first hole section 251 is larger than the inner diameter of the screw hole section 252.

[0052] See Figure 6 In the x-axis direction, a third inclined surface 21 is provided on the side of the side mold 2 near the first surface 244, and the third inclined surface 21 is bent and connected to the first surface 244. The third inclined surface 21 is inclined between the x-axis direction and the y-axis direction; combined with Figure 2 The side mold 2 has an outer side surface on the outside of the joint position 100 in the y-axis direction. The outer side surface is the fifth inclined surface 22, which is inclined between the x-axis direction and the y-axis direction.

[0053] like Figure 2 As described above, after the two side molds 2 are installed at the joint position 100, the distance between the third inclined surface 2 and the fifth inclined surface 22 of the two side molds 2 gradually increases along the x-axis direction and along the direction from the first side to the second side. Additionally, see [link to other documentation]. Figure 6The third inclined plane 21 forms a first angle α with the straight line extending along the x-axis and from the first side to the second side, and the fifth inclined plane 22 forms a second angle β with the straight line. The second angle β is smaller than the first angle α.

[0054] See Figure 7 The end mold 3 is made of metal or other rigid materials such as plastic. The end mold 3 has a second surface 33 facing the negative x-axis and two fourth inclined surfaces 31 connecting opposite sides of the second surface 33. The fourth inclined surfaces 31 are inclined between the x-axis and y-axis directions. The end mold 3 has a second mating hole 32 extending along the x-axis between its two sides. The second mating hole 32 includes a second hole segment 322 and a third hole segment 321 connected sequentially along the positive x-axis. The inner diameter of the second hole segment 322 is smaller than the inner diameter of the third hole segment 321, and a step portion 323 is formed between the second hole segment 322 and the third hole segment 321. See also... Figure 2 The tension spring screw 5 is fixed on the end mold 3 on the side facing the positive x-axis.

[0055] See Figure 8 The spring tie rod bolt 4 includes a bolt 41, a retaining ring 43, and a spring 42; the bolt 41 includes a smooth shaft section 411 and a threaded section 412 connected in sequence; the spring 42 is fitted on the smooth shaft section 411, and the first end 421 of the spring 42 is closer to the threaded section 412 than the second end 422 of the spring 42, and the first end 421 is fixedly connected to the smooth shaft section 411; the retaining ring 43 is slidably fitted on the smooth shaft section 411, and the retaining ring 43 is fixedly connected to the second end 422.

[0056] See Figures 1 to 11 When the flexible protective cover 1, the two side molds 2, the end mold 3, and the spring tie rod bolt 4 are assembled into one unit, the two side molds 2 are connected through the engagement of the positioning hole 13 and the positioning pin 23, and the first end face 142 abuts against the second end face 242, the third end face 143 abuts against the fourth end face 243, and the first inclined surface 141 and the second inclined surface 241 abut against each other. At this time, the two side molds 2 respectively block the joint position 100 from opposite sides in the y-axis direction, and the side molds 2 support the side part 111 from the z-axis direction and the x-axis direction through the engagement of the first inclined surface 141 and the second inclined surface 241.

[0057] Two side molds 2 are connected to the end mold 3. The spring 42 pull rod screw passes through the second mating hole 32 and the first mating hole 25 in sequence. The threaded section 412 mates with the threaded hole section 252. The spring 42 is located in the first hole section 251 and the second hole section 322. The retaining ring 43 is located in the third hole section 321 and abuts against the stepped part 323 in the axial direction of the second mating hole 32. Under the locking of the spring pull rod bolt 4 and the pressure of the spring 42, the first surface 244 and the second surface 33 abut, and the third inclined surface 21 abuts against the fourth inclined surface 31.

[0058] Therefore, the two side molds 2 and end molds 3, which abut against each other in sequence, can provide sufficient support for the flexible protective cover 1 from multiple directions, allowing the flexible protective cover 1 to maintain its shape and resist the internal forces of the concrete. When the end mold 3 is pulled outward by the tension screw 5, under the action of the spring tie bolt 4, the end mold 3 will move while the side mold 2 remains in place. Thus, the abutment relationship between the third inclined surface 21 and the fourth inclined surface 31 is released, and at the same time, the abutment degree between the fifth inclined surface 22 of the side mold 2 and the concrete is weakened. At this time, the side mold 2 is easy to pull out, while the end mold 3 and the side mold 2 remain connected. After the side mold 2 loosens from the concrete, the end mold 3 and the side mold 2 can be pulled out together. Therefore, this setting can realize the simultaneous removal of multiple components in the protective device, greatly reducing the operation steps and reducing the operation difficulty, and can reduce the risk of safety accidents caused by components falling from a height.

[0059] Example of a protection method for the joint of the initial support steel arch frame in a tunnel.

[0060] The method for protecting the tunnel initial support steel arch joint of the present invention is implemented using the tunnel steel arch joint protection device of the present invention.

[0061] See Figure 10 After the excavation of the upper tunnel step is completed and the steel arch frame is fixed, the steel frame 921 and the connecting plate 922 at the joint 92 are located at the bottom of the steel arch frame and inside the surrounding rock 91. The area below the joint 92 is the area to be set up for the lower steel arch frame. It is now necessary to carry out the initial support shotcrete operation in the area where the upper steel arch frame is located corresponding to the joint 92, and it is necessary to ensure that the concrete does not cover the joint 92 so that the joint 92 is exposed and there is enough operating space for the bolting operation of the connecting plate 922.

[0062] Therefore, the protection method of the present invention includes:

[0063] See Figures 1 to 10 First, the flexible protective cover 1 is separated from the side mold 2. The side mold 2, end mold 3, spring tie rod bolt 4, and tension spring screw 5 form an integrated module. Then, at least one side 111 of the flexible protective cover 1 is pried open to enlarge the break 102. The steel frame 921 is inserted through the break 102 into the steel frame through-position 101, and the joint is inserted into the joint position 100. Then, the module is connected to the flexible protective cover 1. At this time, the flexible protective cover 1, the two side molds 2, and the end mold 3 wrap around the joint from the outside and above, effectively preventing concrete from seeping in.

[0064] Then, the initial support shotcrete operation is carried out to form concrete 93. The tunnel steel arch joint protection device protects the joint 92 while also serving as the operating space 900 to be formed (e.g., ...). Figure 16 The mold shown. Combined with... Figure 10 and Figure 11Concrete 93 surrounds the tunnel steel arch joint protection device, and concrete 93 fits with the arc-shaped outer surface 144 and the fifth inclined surface 22 on both sides.

[0065] Subsequently, the protective device for the tunnel steel arch joint was removed. Figure 12 Pulling the tension screw 5 along the negative x-axis causes the end mold 3 to move under the action of the spring tie rod bolt 4, while the side mold 2 remains stationary. This releases the contact between the third inclined surface 21 and the fourth inclined surface 31, and simultaneously weakens the contact between the fifth inclined surface 22 of the side mold 2 and the concrete. At this point, the side mold 2 is easily removed, while the end mold 3 and the side mold 2 remain connected. Therefore, combining... Figures 13 to 15 Once the side mold 2 is loosened from the concrete 93, the module including the end mold 3 and the side mold 2 can be pulled out together.

[0066] Then, the flexible protective cover 1 needs to be removed from the steel frame 921. Similarly, by prying at least one side 111 of the flexible protective cover 1 to widen the break 102, and then pulling the flexible protective cover 1 and deflecting it to a certain position, the steel frame 921 can be removed from the break 102 and the steel frame passage 101 can be removed. Since the main contact surface between the flexible protective cover 1 and the concrete 93 is the outer surface 144, and the outer surface 144 is an arc surface, this design reduces the number of sharp edges on the outer surface 144, thus reducing the degree of fit between the flexible protective cover 1 and the concrete 93. This facilitates the removal of the flexible protective cover 1 from the concrete 93, making the removal operation easier.

[0067] See Figure 16 Then the steel frame can be connected. At this time, the connection 92 is fully exposed and the joint 92 forms sufficient operating space 900 to put on the bolts 951 and tighten the bolts 951.

[0068] Therefore, the tunnel steel arch joint protection device and the tunnel initial support steel arch joint protection method provided by the present invention are quick to implement and simple to operate. After the initial support shotcrete is completed, the protective device can be easily demolded from the concrete, providing sufficient operating space for the docking and installation of the steel arch joint. It also improves the docking quality of the steel arch to a certain extent, ensuring the overall installation quality and stress structure of the tunnel initial support steel arch. The on-site implementation and application effects are significant, and it has high economic benefits.

[0069] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A protective device for the joint of a tunnel steel arch frame, characterized in that: Includes a flexible protective cover, two side molds, and an end mold; The flexible protective cover has a joint position. The flexible protective cover includes a first protective part and a second protective part that are connected to each other. The first protective part blocks the joint position from a first direction, and the second protective part blocks the joint position from a first side from a second direction. The first protective part is provided with a steel frame through-hole, and the steel frame through-hole communicates with the joint position along the first direction; In the second direction, the first protective part includes an end portion away from the second protective part, the first protective part is provided with a break, the break portion is connected to the end portion along the second direction, and in the third direction, the first protective part forms two side portions on opposite sides of the break portion, and the side portions are provided with a first connecting structure disposed along the second direction; In the second direction, a second connecting structure and a third connecting structure are respectively provided on opposite sides of the side mold; The end mold is provided with a fourth connecting structure, which is arranged along the first direction and in the third direction, the fourth connecting structure is provided on each of the opposite sides of the end mold; The two side molds are respectively connected to the two sides, the first connection structure cooperates with the second connection structure, the two side molds respectively block the joint position from the opposite sides in the third direction, and the side molds support the side from the first direction and / or the second direction; Both side molds are connected to the end mold, the third connection structure cooperates with the fourth connection structure, the end mold blocks the joint position from the second side in the second direction, and the end mold restricts the side mold in the second direction and / or the third direction; The first direction is perpendicular to the second direction, the second direction is perpendicular to the third direction, and the third direction is perpendicular to the first direction; The side portion is provided with a first inclined surface, and the side mold is provided with a second inclined surface. Both the first inclined surface and the second inclined surface are inclinedly disposed between the first direction and the second direction. The first inclined plane and the second inclined plane abut against each other; The side portion is provided with a first end face, and the second protective portion is provided with a third end face. Both the first end face and the third end face are arranged in the second direction. The first end face, the first inclined surface and the third end face are bent and connected in sequence. The first connecting structure is provided on the first end face. The side mold is provided with a second end face and a fourth end face, both of which are arranged in the second direction. The second end face, the second inclined surface and the fourth end face are bent and connected in sequence, and the second connecting structure is provided on the second end face. The first end face abuts against the second end face, and the third end face abuts against the fourth end face; The side mold is provided with a third inclined surface, and the end mold is provided with a fourth inclined surface. Both the third inclined surface and the fourth inclined surface are inclinedly disposed between the second direction and the third direction. Along the second direction and along the direction from the first side to the second side, the distance between the third inclined surfaces of the two side molds gradually increases; The third inclined surface abuts against the fourth inclined surface.

2. The tunnel steel arch joint protection device according to claim 1, characterized in that: In the third direction, the side mold has an outer side facing away from the joint position; The outer surface is a fifth inclined surface, which is inclinedly disposed between the second direction and the third direction; Along the second direction and along the direction from the first side to the second side, the distance between the fifth inclined surfaces of the two side molds gradually increases.

3. The tunnel steel arch joint protection device according to claim 2, characterized in that: The third inclined plane forms a first angle with the straight line, and the fifth inclined plane forms a second angle with the straight line, the second angle being smaller than the first angle; The straight line extends along the second direction and in the direction from the first side to the second side.

4. The tunnel steel arch joint protection device according to any one of claims 1 to 3, characterized in that: The flexible protective cover has an outer surface facing away from the joint position, the outer surface being arc-shaped, and the outer surface extending between the first protective portion and the second protective portion.

5. The tunnel steel arch joint protection device according to any one of claims 1 to 3, characterized in that: The tunnel steel arch joint protection device also includes a spring tie rod bolt, which includes a bolt, a retaining ring, and a spring. The bolt comprises an optical axis segment and a threaded segment connected in sequence; The spring is fitted onto the optical axis segment, with the first end of the spring being closer to the threaded segment than the second end of the spring, and the first end being fixedly connected to the optical axis segment; The retaining ring is slidably fitted onto the optical axis segment, and the retaining ring is fixedly connected to the second end; The third connection structure includes a first mating hole, which includes a first hole segment and a threaded hole segment connected in sequence, wherein the inner diameter of the first hole segment is larger than the inner diameter of the threaded hole segment. The fourth connecting structure includes a second mating hole, which includes a second hole segment and a third hole segment. The inner diameter of the second hole segment is smaller than the inner diameter of the third hole segment, and a step is formed between the second hole segment and the third hole segment. The spring pull rod screw passes through the second mating hole and the first mating hole in sequence. The threaded section mates with the threaded hole section. The spring is located in the first hole section and the second hole section. The retaining ring is located in the third hole section and abuts against the stepped portion in the axial direction of the second mating hole.

6. A method for protecting the joint of the initial support steel arch frame of a tunnel, wherein the initial support steel arch frame of the tunnel includes a steel frame and a joint, the joint being connected to the extended end of the steel frame; Its features are: The protection method employs the tunnel steel arch joint protection device as described in any one of claims 1 to 5 above; The protection method includes: Bending at least one of the sides widens the fracture. Insert the steel frame through the break into the steel frame through position, while simultaneously inserting the joint into the joint position; The module, including the side mold and the end mold, is connected to the flexible protective cover; Perform initial sprayed concrete operation.

7. The method for protecting the joint of the initial support steel arch frame in a tunnel according to claim 6, characterized in that: After the initial shotcrete application step, the method further includes: Release the end mold from the restriction of the side mold; Remove the module from the flexible protective cover; Remove the flexible protective cover from the steel frame.

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