A tunnel arch joint protection method

Abstract

The present application relates to a tunnel arch foot joint protection method, which is implemented based on an arch foot joint protection device, the device includes a pad and a pressure plate, a groove is provided on the end face of the pad, and the pressure plate is lifted and lowered above the bottom wall of the groove; the pad is movably provided with a plurality of splints adapted to the peripheral wall of the arch foot on the groove wall, and a linkage structure is provided between the splint and the pressure plate; when the pressure plate moves downward, it drives a plurality of splints to approach synchronously through the linkage structure; it includes the following steps: S1. When constructing a steel arch frame, place the pad at the pre-installed position of the arch foot, and then weld the connecting plate to the peripheral side of the designated position of the arch foot; S2. Insert the arch foot into the groove and abut against the pressure plate, and complete the upper assembly of the steel arch frame; S3. Perform sprayed concrete construction. The present application has the effect of effectively protecting the connecting parts of the arch foot, and can effectively avoid the phenomenon of sinking and deflection caused by excessive load on the local arch foot.

Description

Technical Field

[0001] This application relates to the technical field of building arch foot protection methods, and in particular to a tunnel arch foot joint protection method. Background Art

[0002] With the continuous development of infrastructure construction and complex geological conditions, the number of tunnel projects is gradually increasing. During the installation of the arch frame in the tunnel, the arch frame cannot be formed into a ring at one time. At the arch foot, due to the initial spraying construction, the arch foot is often covered, and the concrete solidifies at the arch foot joint, resulting in the need to deal with the arch foot during the subsequent installation of the arch frame. In current construction, the main protection method is to backfill with virtual soil. After the initial spraying of concrete is completed, the virtual soil and concrete are then cleaned up, which will affect the construction progress.

[0003] The Chinese patent with the publication number CN113605939A in the related art proposes a method for positioning the connecting plate of the tunnel arch foot and constructing the steel arch frame, including two or more box bodies. Each box body includes a positioning plate and a cover body. A cavity for accommodating the connecting plate is formed in the positioning plate. Limiting holes corresponding to the connecting holes on the connecting plate are provided at the bottom of the positioning plate. A break groove is provided in the middle of the cover body. The cover body covers the positioning plate and blocks the connecting holes on the connecting plate. A limiting member is connected between adjacent two positioning plates. When using this tooling for construction, first fix the positioning plates on the pre-installed positions of the corresponding steel arch frames on both sides respectively, then fix the connecting plate on the positioning plate, install the limiting member between adjacent two positioning plates and adjust it. The steel arch frames with a preset size are spliced between the corresponding arch feet on both sides. After fixing the steel arch frame, install the cover body on the positioning plate, spray concrete, and remove the cover body, positioning plate and limiting member after the concrete solidifies. This invention can effectively prevent the blockage of the connecting holes.

[0004] The above-mentioned related technologies have the following defects: The arch foot mainly plays a role of supporting and bearing in the steel arch frame, and the connecting plate is used to connect multiple arch feet to improve the overall structural stability of the steel arch frame. However, in the actual support of the steel arch frame in the tunnel, it is difficult to ensure that the load borne by each arch foot is the same. When the local arch foot is subjected to a large force, due to the arc surface of the tunnel inner wall, the arch foot has a tendency to sink and deflect, which easily causes the overall bearing instability of the steel arch frame and affects the support effect. Summary of the Invention

[0005] In order to improve the problem that the support performance is affected when the local arch foot sinks and deflects due to excessive force, this application provides a tunnel arch foot joint protection method.

[0006] A tunnel arch foot joint protection method provided by this application adopts the following technical solutions:

[0007] A tunnel arch foot joint protection method is implemented based on an arch foot joint protection device, wherein the connection plate of the arch foot joint is not located on the end face of the arch foot. The device comprises a cushion block and a pressure plate arranged in the cushion block, wherein a groove for inserting the arch foot is provided on the end face of the cushion block, and the pressure plate is lifted and arranged above the bottom wall of the groove; when the connection plate contacts the upper end face of the cushion block, the pressure plate does not contact the bottom wall of the groove;

[0008] The pad is movably provided with a plurality of clamping plates adapted to the peripheral wall of the arch foot on the groove wall, and a linkage structure is provided between the clamping plates and the pressure plate; when the pressure plate moves downward, the plurality of clamping plates are driven to approach synchronously through the linkage structure;

[0009] The protection method includes the following steps:

[0010] S1. When constructing the steel arch frame, place the pad at the pre-installed position of the arch foot, and then weld the connecting plate to the surrounding side of the designated position of the arch foot;

[0011] S2. Insert the processed arch foot into the groove and abut against the pressure plate, and complete the upper assembly of the steel arch frame;

[0012] S3. Carry out shotcrete construction.

[0013] Furthermore, the linkage structure includes a sliding rod fixedly connected to the bottom of the pressure plate, the cushion block is provided with a receiving groove for receiving the sliding rod on the bottom wall of the groove, the cushion block is provided with a plurality of surface grooves distributed in an equidistant circular array with the axis of the sliding rod as the central axis on the groove wall, the lower part of the surface groove extends to connect with the receiving groove, and the upper part extends to a position close to the clamping plate, and a hinge assembly for hingedly connecting the sliding rod and the clamping plate is provided in the surface groove.

[0014] Furthermore, the hinge assembly includes a folding rod, the bending portion of the folding rod is hinged on the wall of the surface groove and the inner corner of the folding rod faces the groove, the upper part of the folding rod is hinged to the clamping plate, and the lower part is hinged to the peripheral wall of the sliding rod.

[0015] Furthermore, a tie rod is fixedly connected between the two straight rod sections of the folding rod.

[0016] Furthermore, a side of the clamping plate close to the middle of the groove is provided with an anti-slip structure.

[0017] Furthermore, a first pressure sensor is embedded on one side of the clamping plate close to the middle of the groove, and a plurality of the first pressure sensors are marked with the contact position with the arch foot and are commonly connected to a PLC controller, and the PLC controller is connected to a display screen.

[0018] ​Further, the PLC controller is connected with an audible and visual alarm.

[0019] Further, a second pressure sensor is embedded in the bearing plate, and the second pressure sensor is connected with the PLC controller.

[0020] Further, an anti-falling nut is threadedly connected to the sliding rod, and an expansion panel is fixedly connected to the end face of the anti-falling nut.

[0021] Further, before performing the step S3, a release agent is coated on the periphery of the cushion block or an isolation film is covered.

[0022] In summary, the present application at least includes the following beneficial technical effects;

[0023] 1. By arranging the cushion block, the arch foot can be elevated, so that the concrete flowing to the tunnel floor during shotcrete will not directly cover the mounting holes of the connecting plate on the arch foot, which can effectively protect the connecting parts of the arch foot; at the same time, after the arch foot abuts against the bearing plate, the bearing plate drives multiple clamping plates to embrace and clamp the arch foot through the linkage structure, and as the arch foot has a greater tendency to sink, the embracing effect of the multiple clamping plates on the arch foot is better, which can effectively avoid the phenomena of sinking and deflection caused by excessive local load on the arch foot, and ensure the effective supporting effect of the arch foot on the steel arch as much as possible;

[0024] 2. By arranging the folding rod in the surface groove, and then hinging the two ends of the folding rod to the clamping plate and the sliding rod respectively, and also arranging the tension bar in the folding rod to reinforce the structural strength of the folding rod, the bearing plate can effectively and timely push the clamping plate to clamp the arch foot through the folding rod after supporting the arch foot;

[0025] 3. By arranging the first pressure sensor on the inner side of the clamping plate, marking its setting position and connecting it with the PLC controller, the reaction force received by the multiple pressure plates when abutting against the arch foot can be detected in real time. Thus, when the arch foot has a tendency to deflect, the value detected by the first pressure sensor corresponding to the deflection direction increases significantly, and the construction personnel can learn about it in time through the display screen or the audible and visual alarm. When applied to the construction of some high-difficulty tunnels, especially underwater tunnels, the construction safety can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic cross-sectional structure view of the arch foot joint protection device of the embodiment of the present application.

[0027] Reference numerals: 1, cushion block; 2, bearing plate; 3, groove; 4, clamping plate; 5, sliding rod; 6, receiving groove; 7, surface groove; 8, folding rod; 9, tension bar; 10, first pressure sensor; 11, second pressure sensor; 12, anti-falling nut; 13, expansion panel. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The technical solution of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0029] An embodiment of the present application discloses a method for protecting the arch foot joint. This protection method is implemented based on an arch foot joint protection device. The connecting plate of the arch foot joint targeted by it is not located at the end face of the arch foot. Refer to Figure 1 , this arch foot joint protection device includes a cushion block 1 and a bearing plate 2 arranged in the cushion block 1. The cushion block 1 can be made of steel pipes welded with reinforcing ribs or directly precast with concrete. Moreover, a plurality of threaded holes corresponding to the mounting holes on the connecting plate can be opened on the upper end face of the cushion block 1. A groove 3 for inserting the arch foot is opened on the end face of the cushion block 1. Among them, the extending direction of the groove 3 should be collinear with the stress direction of the arch foot. The bearing plate 2 is arranged to be lifted and lowered above the bottom wall of the groove 3; when the connecting plate on the arch foot abuts against the upper end face of the cushion block 1, the bearing plate 2 does not contact the bottom wall of the groove 3.

[0030] A plurality of clamping plates 4 that are fitted with the peripheral wall of the arch foot are movably arranged on the groove wall of the groove 3 of the cushion block 1. When the arch foot is a square steel, the clamping plates 4 are set to four and made of angle steel; when the arch foot is a round steel, the clamping plates 4 are at least three and made of arc plates. A linkage structure is arranged between the clamping plates 4 and the bearing plate 2. When the bearing plate 2 moves downward, it drives a plurality of clamping plates 4 to approach synchronously through the linkage structure.

[0031] Specifically, refer to Figure 1 , the linkage structure includes a sliding rod 5 fixedly connected to the bottom of the bearing plate 2. The cushion block 1 is provided with a receiving groove 6 for receiving the sliding rod 5 on the bottom wall of the groove 3. The cushion block 1 is provided with a plurality of surface grooves 7 on the groove wall of the groove 3 that are circumferentially arrayed at equal intervals with the axis of the sliding rod 5 as the center line. The lower part of the surface groove 7 extends to communicate with the receiving groove 6, and the upper part extends to be close to the clamping plate 4. An articulated component for articulated connection between the sliding rod 5 and the clamping plate 4 is arranged in the surface groove 7; the articulated component includes a folding rod 8. The bent part of the folding rod 8 is articulated on the groove wall of the surface groove 7, and the inner angle of the folding rod 8 faces the groove 3. The upper part of the folding rod 8 is articulated with the clamping plate 4, and the lower part is articulated with the peripheral wall of the sliding rod 5. Moreover, an avoidance groove is provided at the articulated part of the folding rod 8 and the sliding rod 5 to prevent the folding rod 8 from being stuck when articulated and flipped with the sliding rod 5.

[0032] After such setting, the arch springing can be elevated by setting the spacer block 1, so that the concrete flowing to the tunnel floor during shotcrete will not directly cover the installation holes of the connecting plates on the arch springing, which can effectively protect the connecting members of the arch springing. This enables the shotcrete of the upper bench arch springing to be in place at one time, saving labor and facilitating the protection of the arch springing; at the same time, it avoids the poor compaction of concrete caused by reserving connection spaces with backfilled loose slag in the past, and the initial support flatness is difficult to control.

[0033] At the same time, after the arch springing abuts against the bearing pressure plate 2, as the arch springing pushes the bearing pressure plate 2 downward, the bearing pressure plate 2 pushes the sliding rod 5 downward and drives the upper part of the folding rod 8 to flip towards the side close to the inside of the groove 3, so that the plurality of clamping plates 4 jointly embrace and clamp the arch springing, and as the arch springing has a greater tendency to sink, the embracing effect of the plurality of clamping plates 4 on the arch springing is better, which can effectively avoid the phenomena of sinking and deflection of the local arch springing after excessive load, and ensure the effective supporting effect of the arch springing on the steel arch frame as much as possible.

[0034] Considering that the arch springing bears a large load, the folding rod 8 needs to have strong embracing performance when embracing the arch springing; therefore, referring to Figure 1 , a tension bar 9 is fixedly connected between the two straight rod sections of the folding rod 8, and both ends of the tension bar 9 are welded and fixed on the folding rod 8; and an anti-slip structure is arranged on the side of the clamping plate 4 close to the middle of the groove 3, and the anti-slip structure can be a wear-resistant rubber layer, can be an anti-slip groove, or can be anti-slip teeth.

[0035] After such setting, the setting of the tension bar 9 significantly improves the structural strength of the folding rod 8, and the setting of the anti-slip structure improves the anti-slip performance between the clamping plate 4 and the arch springing, so that the arch springing is not easy to sink after being embraced and clamped by the plurality of clamping plates 4, so as to ensure the stable supporting effect of the arch springing.

[0036] In the construction of some high-difficulty tunnels, especially underwater tunnels, the change of the bearing performance of the arch springing will seriously affect the overall supporting performance of the steel arch frame, and in serious cases, safety accidents will occur. When the arch springing sinks or deflects, it is difficult for construction workers to find with the naked eye, and preventive measures cannot be taken in advance to ensure construction safety.

[0037] In view of this, referring to Figure 1 , a first pressure sensor 10 is embedded on the side of the clamping plate 4 close to the middle of the groove 3. The plurality of first pressure sensors 10 are marked with the orientation of the contact part with the arch springing and are jointly connected to a PLC controller. The PLC controller is connected to a display screen, and at the same time, the PLC controller is also connected to an audible and visual alarm; a second pressure sensor 11 is embedded on the bearing pressure plate 2, and the second pressure sensor 11 is connected to the PLC controller.

[0038] After setting like this, when the arch foot is pressed tightly on the bearing plate 2, the second pressure sensor 11 detects the bearing capacity of the arch foot in real time and displays it on the display screen through the PLC controller. When the bearing capacity of the arch foot suddenly changes, the display screen will display the value of arch foot overload, and the sound and light alarm will sound to prompt the construction personnel to deal with it in time. After multiple clamping plates 4 clamp the arch foot, the first pressure sensor 10 monitors the lateral pressure of the arch foot in real time. When the arch foot has a tendency to deflect in a certain direction, the value detected by the corresponding first pressure sensor 10 in this direction suddenly changes, which can be displayed on the display screen through the PLC controller, and the sound and light alarm will also give a warning so that the construction personnel can deal with it in time, improving the safety during the construction process.

[0039] To further avoid the phenomenon of the arch foot falling caused by the difficulty of the clamping plate 4 to stably clamp the arch foot due to excessive load on the arch foot, referring to Figure 1 , a fall-preventing nut 12 is threadedly connected to the sliding rod 5, and an expansion panel 13 is fixedly connected to the end face of the fall-preventing nut 12. The setting of the fall-preventing nut 12 effectively reduces the falling stroke of the bearing plate 2 to prevent the overall instability of the steel arch frame due to excessive falling of the arch foot in extreme cases; and the setting of the expansion panel 13 increases the contact area between the fall-preventing nut 12 and the bottom wall of the groove 3, making the fall-preventing nut 12 more stable when bearing the bearing plate 2.

[0040] A tunnel arch foot joint protection method of the present application is realized based on the above-mentioned tunnel arch foot joint protection device, and includes the following steps:

[0041] S1. When constructing the steel arch frame, place the cushion block 1 at the pre-installed position of the arch foot, and then weld the connecting plate on the periphery of the designated position of the arch foot;

[0042] S2. Insert the processed arch foot into the groove 3 and abut against the bearing plate 2, and complete the upper assembly of the steel arch frame;

[0043] S3. First coat a release agent or cover an isolation film on the periphery of the cushion block 1, and then carry out shotcrete construction.

[0044] Coating a release agent or covering an isolation film on the periphery of the cushion block 1 helps to conveniently peel off the solidified concrete block from the cushion block 1 after the concrete to be sprayed solidifies, so that the cushion block 1 can be reused.

[0045] The implementation principle of a method for protecting the tunnel arch springing joint in an embodiment of this application is as follows: By setting the spacer block 1, the arch springing can be elevated, so that the concrete flowing to the tunnel floor during shotcrete will not directly cover the mounting holes of the connecting plate on the arch springing, which can effectively protect the connecting members of the arch springing; at the same time, after the arch springing abuts against the bearing plate 2, the bearing plate 2 drives multiple clamping plates 4 to embrace and clamp the arch springing through a linkage structure, and as the arch springing has a greater tendency to sink, the embracing effect of the multiple clamping plates 4 on the arch springing is better, which can effectively avoid the phenomena of sinking and deflection caused by excessive local load on the arch springing, and ensure the effective supporting effect of the arch springing on the steel arch as much as possible.

[0046] The above are all preferred embodiments of this application, and the protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. A tunnel arch foot joint protection method, characterized in that: Based on the implementation of the arch foot joint protection device, the connecting plate of the arch foot joint is not located on the end surface of the arch foot. The device comprises a cushion block (1) and a pressure plate (2) arranged in the cushion block (1). A groove (3) for inserting the arch foot is opened on the end surface of the cushion block (1), and the pressure plate (2) is arranged to be raised and lowered above the bottom wall of the groove (3); when the connecting plate contacts the upper end surface of the cushion block (1), the pressure plate (2) does not contact the bottom wall of the groove (3); The cushion block (1) is provided with a plurality of clamping plates (4) adapted to the peripheral wall of the arch foot on the groove wall of the groove (3), and a linkage structure is provided between the clamping plates (4) and the pressure plate (2); when the pressure plate (2) moves downward, the plurality of clamping plates (4) are driven to move synchronously closer through the linkage structure; The protection method comprises the following steps: S1. During the construction of the steel arch, the pad (1) is placed at the pre-installed position of the arch foot, and then the connecting plate is welded to the surrounding side of the arch foot at the designated position; S2. Insert the processed arch foot into the groove (3) and abut against the pressure plate (2), and complete the upper assembly of the steel arch; S3. Carry out shotcrete construction.

2. A tunnel arch foot joint protection method according to claim 1, characterized in that: The linkage structure comprises a sliding rod (5) fixedly connected to the bottom of the pressure plate (2); the cushion block (1) is provided with a receiving groove (6) for receiving the sliding rod (5) on the bottom wall of the groove (3); the cushion block (1) is provided with a plurality of surface grooves (7) distributed in an equidistant circular array with the axis of the sliding rod (5) as the central axis on the groove wall of the groove (3); the lower part of the surface groove (7) extends to be connected with the receiving groove (6) and the upper part extends to be close to the clamping plate (4); and a hinge assembly for hingedly connecting the sliding rod (5) and the clamping plate (4) is arranged in the surface groove (7).

3. A tunnel arch foot joint protection method according to claim 2, characterized in that: The hinge assembly comprises a folding rod (8), the bending portion of the folding rod (8) is hinged on the groove wall of the surface groove (7) and the inner corner of the folding rod (8) faces the groove (3), the upper portion of the folding rod (8) is hinged to the clamping plate (4), and the lower portion is hinged to the peripheral wall of the sliding rod (5).

4. A tunnel arch foot joint protection method according to claim 3, characterized in that: A tension rod (9) is fixedly connected between the two straight rod sections of the folding rod (8).

5. A tunnel arch foot joint protection method according to claim 1, characterized in that: An anti-slip structure is provided on one side of the clamping plate (4) close to the middle of the groove (3).

6. A tunnel arch foot joint protection method according to claim 1, characterized in that: A first pressure sensor (10) is embedded on one side of the clamping plate (4) close to the middle of the groove (3); a plurality of the first pressure sensors (10) are marked with the contact position with the arch foot and are commonly connected to a PLC controller; the PLC controller is connected to a display screen.

7. A tunnel arch foot joint protection method according to claim 6, characterized in that: The PLC controller is connected with an audible and visual alarm.

8. A tunnel arch foot joint protection method according to claim 7, characterized in that: A second pressure sensor (11) is embedded in the pressure-bearing plate (2), and the second pressure sensor (11) is connected to the PLC controller.

9. A tunnel arch foot joint protection method according to claim 2, characterized in that: The slide bar (5) is threadedly connected with an anti-falling nut (12), and the end surface of the anti-falling nut (12) is fixedly connected with an expansion panel (13).

10. A tunnel arch foot joint protection method according to claim 1, characterized in that: Before carrying out step S3, a release agent is first applied to the peripheral side of the cushion block (1) or an isolation film is covered.

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