Multi-petal, combinable anchor centering support device and its construction method

Abstract

The present invention discloses a multi-lobe, combinable anchor centering support device, which relates to the fields of water conservancy and hydropower, roads, bridges, and geotechnical engineering reinforcement. It includes an anchor and a centering support; the centering support includes a first centering support lobe, a second centering support lobe, and a centering ridge frame; the first centering support lobe and the second centering support lobe wrap the anchor, and the first centering support lobe and the second centering support lobe are connected by a fixing device, and the fixing device includes a first buckle tooth, a first buckle door, a second buckle door, and a second buckle tooth. The present invention solves the problems that in the current construction process of the anchor, due to the fact that traditional centering supports are mostly directly processed by on-site workers, the production quality is uncontrollable, and the anchor steel bars cannot be effectively centered. The present invention also relates to a construction method of this multi-lobe, combinable anchor centering support device.

Description

Technical Field

[0001] The present invention relates to the fields of water conservancy and hydropower, roads, bridges, and geotechnical engineering reinforcement, and more specifically, it is a multi-petal, combinable anchor centering support device. The present invention also relates to a construction method for such a multi-petal, combinable anchor centering support device. Background Art

[0002] The geotechnical anchoring technology is an in-situ reinforced soil technology used to improve the stability of slopes, retaining walls, and excavated bodies, etc. It can be traced back to the coal mine reinforcement project in North Wales in 1890, and later formed the geotechnical excavation support theory represented by the "New Austrian Tunneling Method". With more than a century of development, this technology has been widely applied in many engineering fields around the world, especially achieving more remarkable results in water conservancy and hydropower. Currently, due to its favorable characteristics such as "common materials, flexible applicability, rapid construction, appropriate cost, and guaranteed reinforcement effect", anchor support has become an important technology for the support and reinforcement of dam foundations, slopes, and underground caverns in water conservancy and hydropower projects.

[0003] In a broad sense, an anchor is composed of multiple components, including: 1) high-strength threaded steel bars, which are the core components of the anchor and are manually pushed into pre-completed drill holes; 2) cement slurry and other gelled material envelopes, which are injected into the bottom of the drill hole through a grouting pipe to bond the rod body and the surrounding rock and soil masses into a whole; 3) steel bar connectors, which are used for end-to-end connection when the length of the anchor exceeds that of a single processed steel bar; 4) centering supports, which center the steel bars in the drill hole; 5) grouting pipes and exhaust pipes, which are used to inject slurry and discharge excess gas in the drill hole; 6) anchor heads and surface layers, which are the end resistance bodies for the anchor to bear loads.

[0004] The service life of an anchor depends on its durability, and the greatest threat to durability comes from the corrosion of the anchor steel bars. The environmental factors causing corrosion to the anchor include the aggressiveness of rock and soil media and groundwater, bimetallic action, and stray currents existing in the formation, etc. Under certain conditions, the acidity and alkalinity (pH value), chlorides, and sulfates in the rock and soil media can all cause corrosion to the anchoring structures.

[0005] As the connection and transition layer between the anchor and the surrounding rock and soil masses - the cement slurry envelope, it is not only a load conduction medium for forming the "formation deformation" → "anchor force", but also an effective protective barrier against the aforementioned corrosion of the anchor - the high-alkaline environment formed by it can form a stable and dense oxide film on the surface of the anchor bar metal and keep it in a passivated state, which has a good protective effect on the anchor bar.

[0006] Based on this, in order to reduce the corrosion of the anchor rod by external media (groundwater, air, etc.), meet the durability requirements of the anchor rod within the design service life, and ensure the safety and effectiveness of the anchoring project, the thickness of the cement slurry protective layer around the steel bar is clearly stipulated in the relevant domestic and foreign design and construction specifications (such as the European standard BS EN14490:2010 "Execution of special geotechnical works. Soilnailing", the national standard GB50086-2015 "Technical Specification for Geotechnical Anchor and Sprayed Concrete Support Engineering", etc.), to ensure that its filling is continuous and complete and the thickness is uniform.

[0007] In order to ensure that the thickness of the cement slurry inclusion of the anchor rod meets the requirements of the specification, in the current anchor rod process, the centering bracket is generally installed at a certain distance (2m to 3m) along the axis of the steel bar to ensure that the anchor rod body is located in the center of the drill hole, thereby controlling the space around the rod body (i.e. the thickness of the slurry inclusion in the later stage). In the actual construction process, the traditional anchor rod centering bracket has the following prominent problems:

[0008] 1) The centering bracket is usually processed by on-site workers, the quality is uncontrollable, and the centering effect is poor

[0009] Common centering brackets are divided into two categories, which are generally processed in batches by workers before on-site anchoring construction:

[0010] The first method uses PVC hard plastic pipe as raw material. After making several cuts along the axial direction of the pipe (3 cuts with a circumferential angle of 120° or 4 cuts with a circumferential angle of 90°), axial pressure is applied to force the strips between the cuts of the plastic pipe to form an arch.

[0011] The second method is to directly use φ6, φ8 or other small diameter round steel bars as raw materials, bend them manually or mechanically to form an arc or broken line arch, and then directly weld them together with the anchor steel bars by electric welding.

[0012] For the above two types of centering brackets, since there are no strict processing control standards for each project, different construction units use different methods, making the quality of the finished products uncontrollable. The PVC centering bracket formed by extrusion may form three or four flanges of different heights due to different lengths of incisions and asymmetric positions, which ultimately makes it impossible for the anchor rod to be effectively centered in the drilled hole. The problem with the centering bracket formed by welding is even more obvious - since the round steel bars are processed separately, the arch characteristics of each finished product may be different, and when the flange height is not obvious, it is impossible to form a sufficient cement slurry protective layer thickness.

[0013] 2) The centering bracket is not flexible to install and the positioning is not reliable, which may cause deviation and affect the centering effect

[0014] On the one hand, for the installation of common PVC rigid plastic centering brackets, each new one needs to be sleeved from one end of the anchor rod and then gradually pushed to the required position. When the length of the anchor rod is relatively large (such as 9 m), workers need to run back and forth to complete the installation of the required number of centering brackets, thus significantly increasing the on-site operation time. On the other hand, when the diameter of the anchor rod is relatively close to the inner diameter of the PVC rigid plastic pipe used on site, the centering bracket will be severely hindered by the steel bar threads and the pushing will not be smooth. At this time, if the centering bracket is forcibly pulled, it is easy to deform or be damaged.

[0015] On the other hand, the centering bracket should be firmly connected to the anchor rod body so that when the overall structure of the subsequent anchor rod is sent into the drill hole, the arched part of the centering bracket will not be misaligned when being squeezed and rubbed by the hole wall. When fixing the PVC rigid plastic centering bracket on site, there is no fixing measure and it is generally rather casual. The common form is to wind and tie it with thin iron wire. The problem brought by the above-mentioned tying is that because it is not convenient for operation (the iron wire needs to shuttle between the centering bracket and the rod body), the operation efficiency is low, and the tying effect is not very ideal. Loose running positions often occur, affecting the established distance between each bracket. When the distance between adjacent centering brackets is too large, the steel bar rod body between them will form a sag under its own weight, resulting in uneven thickness of the cement slurry protective layer.

[0016] Therefore, it is necessary to develop a simple, practical, efficient and economical multi-petal, combinable anchor rod centering bracket device. Summary of the Invention

[0017] The first object of the present invention is to overcome the deficiencies of the above-mentioned background technology and provide a multi-petal, combinable anchor rod centering bracket device.

[0018] The second object of the present invention is to provide a construction method for this multi-petal, combinable anchor rod centering bracket device.

[0019] To achieve the above first object, the technical solution of the present invention is: a multi-petal, combinable anchor rod centering bracket device, characterized in that: it includes an anchor rod and a centering bracket that wraps the anchor rod;

[0020] The centering bracket includes a first centering bracket petal, a second centering bracket petal and a centering ridge frame;

[0021] The first centering bracket petal and the second centering bracket petal have the same structure. The first centering bracket petal and the second centering bracket petal wrap the anchor rod. The left and right ends of the first centering bracket petal and the second centering bracket petal are both connected by a fixing device. There are two centering ridge frames in the middle part of the first centering bracket petal and the second centering bracket petal;

[0022] The fixing device comprises a first buckle located at the upper end of the first pair of stent flaps, a first buckle door located at the lower end of the first pair of stent flaps, a second buckle door located at the upper end of the second pair of stent flaps, and a second buckle located at the lower end of the second pair of stent flaps; the first buckle tooth matches the second buckle door, and the first buckle door matches the second buckle tooth;

[0023] There is a centering stent-flap splicing seam between the first pair of centering stent-flaps and the second pair of centering stent-flaps.

[0024] In the above technical solution, binding grooves are provided at both left and right ends of the first pair of center stent petals and the second pair of center stent petals.

[0025] In the above technical solution, the left and right ends of the first pair of central stent flaps and the second pair of central stent flaps form a straight line, and the structure of the middle part of the first pair of central stent flaps and the second pair of central stent flaps is concave at the left and right ends and arched in the middle.

[0026] In the above technical solution, the size of the centering bracket is 160mm×35mm×25mm, and the tube wall thickness is 4mm.

[0027] In the above technical solution, the first snap door and the second snap door are formed integrally with the centering bracket, and the first snap door and the second snap door are flat "U"-shaped frames with a thickness of 4 mm, and the net space inside the frame is 6 mm × 12 mm, which serves as an occlusal channel for the subsequent assembly of the first centering bracket flap and the second centering bracket flap;

[0028] The first buckle tooth and the second buckle tooth are integrally formed with the centering bracket.

[0029] In the above technical solution, the binding groove is arranged at 10mm-20mm on both ends of the centering bracket, and the depth is 2mm.

[0030] In order to achieve the above second purpose, the technical solution of the present invention is: a construction method of a multi-petal, combinable anchor rod centering support device, characterized in that it includes the following steps:

[0031] Step 1: Confirm the location, direction, hole diameter and hole depth of the anchor hole and start drilling. When the drilling is completed, extend the water pipe to the bottom of the hole and flush the hole with a large flow of water.

[0032] Step 2: Prepare anchor rods of different lengths required for the anchoring project;

[0033] Step 3: Customize the molds for the first pair of centering stent flaps and the second pair of centering stent flaps, and carry out standardized mass production in the workshop;

[0034] Step 4: Preliminarily fit the first pair of center stent flaps and the second pair of center stent flaps relatively to the anchor rod along the center stent flap joint seam;

[0035] Step 5: Merge the first locking teeth by pressing and then pass them through the second locking door. After releasing the pressing force, the first locking teeth naturally separate to both sides and are hooked on the second locking door; merge the second locking teeth by pressing and then pass them through the first locking door. After releasing the pressing force, the second locking teeth naturally separate to both sides and are hooked on the first locking door.

[0036] Step 6: Use iron wire or string to wind and firmly bind in the lashing channels at the left and right ends of the first pair of middle support petals and the second pair of middle support petals, completing the installation and positioning of a single middle support on the anchor rod.

[0037] Step 7: Arrange and fix the grouting pipe and the exhaust pipe on the anchor rod body.

[0038] Step 8: Send the entire anchor rod into the drill hole and push it manually. During the whole process, maintain a slow and uniform pushing speed to ensure that the materials of each part of the anchor rod are not deformed or damaged due to extrusion, friction, etc.

[0039] Step 9: After the installation of the anchor rod is completed, grout from the bottom through the grouting pipe hole. As the liquid level of the grout rises, discharge the residual gas in the drill hole through the exhaust pipe. Finally, when the grout reaches the hole opening, seal the hole to complete the construction.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] 1) The present invention solves the problems that in the current construction process of anchor rods, due to the fact that traditional middle supports are mostly directly processed by on-site workers, the production quality is uncontrollable and the anchor rod steel bars cannot be effectively centered. At the same time, it also solves the problems of low installation efficiency of the anchor rod structural components and difficulty in meeting the engineering requirements for the spacing of the middle supports caused by the inflexible installation and unreliable positioning of the traditional middle supports.

[0042] 2) The present invention adopts industrial standard mass production, with stable and reliable quality; affected by on-site construction equipment, raw materials, and the technical level of workers, traditional middle supports cannot guarantee the unity of the structural characteristics of each batch of middle supports, resulting in uneven construction quality of anchor rods and certain safety hazards in the project; the middle support of the present invention is designed based on standard model drawings and industrially batch processed, with clear requirements for the main external dimension characteristics of the middle support, ensuring that the finished products have the same specifications and reliable quality, and realizing the effective centering of the anchor rod.

[0043] 3) The present invention greatly optimizes the installation and positioning methods of the centering support, reduces repetitive labor, and improves the construction efficiency of bolt assembly; the traditional centering support can only be sleeved from the end of the bolt, and as the length of the bolt increases, the on-site repetitive labor also increases; the advantage of the centering support of the present invention is that through the "split opening and closing + buckle" design, it can be instantly buckled and installed or disassembled separately at any part of the bolt at any time, and there will be no problem that the centering support cannot be pushed and positioned due to the mismatch between the inner diameter of the centering support and the diameter of the steel bar. This device greatly reduces the operation difficulty and time of workers, saves the construction period, and is of great significance for slope emergency reinforcement projects.

[0044] 4) The present invention realizes the firm binding of the centering support, and the bolt is effectively centered throughout the whole length; the centering support of the present invention uses a pressing buckle to quickly bind the two split supports to the bolt rod body, and further by setting special channels on the wall edge, and by selecting thick and strong iron wires or strings for winding and binding fixation, a more effective circumferential binding is formed; compared with the traditional random winding with tape or thin iron wires, it can bind the centering support to the bolt steel bar more efficiently and firmly, ensuring the effective distance between the centering supports. On this basis, the bolt can have no obvious sag throughout the whole length, realizing the uniform thickness of the cement slurry protective layer and ensuring the durability of the bolt. Brief Description of the Drawings

[0045] Figure 1 It is a structural schematic diagram of the present invention.

[0046] Figure 2 It is Figure 1 The sectional view at A-A in

[0047] Figure 3 It is Figure 1 The sectional view at B-B in

[0048] Figure 4 It is Figure 1 The sectional view at C-C in

[0049] Figure 5 It is Figure 1 The sectional view at D-D in Detailed Description of the Preferred Embodiments

[0050] The following will describe in detail the implementation of the present invention with reference to the drawings, but they do not constitute a limitation to the present invention, and are only for illustration. At the same time, the advantages of the present invention will become clearer and easier to understand through the description.

[0051] Referring to the drawings, it can be seen that: the multi-lobe, combinable bolt centering support device is characterized in that: it includes a bolt 1 and a centering support 2 that wraps the bolt 1;

[0052] The centering support 2 includes a first centering support flap 21, a second centering support flap 22, and a centering ridge frame 23;

[0053] The first centering support flap 21 and the second centering support flap 22 have the same structure. The first centering support flap 21 and the second centering support flap 22 wrap the anchor rod 1. The left and right ends of the first centering support flap 21 and the second centering support flap 22 are both connected by a fixing device 3. There are two centering ridge frames 23 in the middle parts of the first centering support flap 21 and the second centering support flap 22.

[0054] The fixing device 3 includes a first buckle tooth 211 at the upper end of the first centering support flap 21, a first buckle door 212 at the lower end of the first centering support flap 21, a second buckle door 222 at the upper end of the second centering support flap 22, and a second buckle tooth 221 at the lower end of the second centering support flap 22. The first buckle tooth 211 matches the second buckle door 222, and the first buckle door 212 matches the second buckle tooth 221.

[0055] There is a centering support flap splicing seam 24 between the first centering support flap 21 and the second centering support flap 22.

[0056] Binding channels 25 are provided at the left and right ends of the first centering support flap 21 and the second centering support flap 22.

[0057] The left and right ends of the first centering support flap 21 and the second centering support flap 22 form a straight channel. The structure of the middle parts of the first centering support flap 21 and the second centering support flap 22 is concave at the left and right ends and arched in the middle.

[0058] The construction method of the multi-flap and combinable anchor rod centering support device is characterized by including the following steps:

[0059] Step 1: Confirm the position, direction, aperture, and hole depth of the anchor rod drilling according to the requirements of the construction drawings, and start drilling. After the drilling is completed, insert a water pipe to the bottom of the hole and flush the drilling hole with a large flow of water;

[0060] Step 2: Prepare anchor rods 1 with different lengths required for the anchoring project;

[0061] Step 3: Customize the molds for the first centering support flap 21 and the second centering support flap 22, and carry out standardized mass production in the workshop;

[0062] Step 4: Initially relatively fit the first centering support flap 21 and the second centering support flap 22 along the centering support flap splicing seam 24 on the anchor rod 1;

[0063] Step 5: Press the first buckle teeth 211 to merge them and pass through the second buckle door 222. After releasing the pressing force, the first buckle teeth 211 naturally separate to both sides and hang on the second buckle door 222. Press the second buckle teeth 221 to merge them and pass through the first buckle door 212. After releasing the pressing force, the second buckle teeth 221 naturally separate to both sides and hang on the first buckle door 212.

[0064] Step 6: Use wire or rope to wrap and firmly bind in the binding grooves 25 at the left and right ends of the first centering stent petal 21 and the second centering stent petal 22 to complete the installation and positioning of the single centering stent 2 on the anchor rod 1;

[0065] Step 7: Arrange and fix the grouting pipe and the exhaust pipe on the rod body of the anchor rod 1;

[0066] Step 8: Push the anchor rod 1 as a whole into the borehole manually, and keep a slow and uniform pushing speed during the whole process to ensure that the materials at various parts of the anchor rod 1 are not deformed and damaged by extrusion, friction, etc.;

[0067] Step 9: After the anchor rod 1 is installed, grouting is carried out from the bottom of the hole through the grouting pipe hole. As the slurry level rises, the residual gas in the borehole is discharged through the exhaust pipe. Finally, the slurry reaches the hole mouth to complete the hole sealing and the construction is completed.

[0068] In actual use, the centering ridge frame 23 is used to center the anchor rod 1 in the drilled hole to prevent the unfavorable situation that the cement slurry on one side of the anchor rod 1 steel bar is too thin; the buckles and buckles are used in pairs to realize the combined splicing of the first centering bracket flap 21 and the second centering bracket flap 22; the binding grooves 25 at the left and right ends are used to place wires or ropes to further firmly bind and fix the combined first centering bracket flap 21 and the second centering bracket flap 22 to the anchor rod 1 rod body.

[0069] The original material used for processing the centering bracket 2 of the present invention is PVC hard plastic. The size of the first centering bracket petal 21 and the second centering bracket petal 22 after being assembled into a whole by buckles is 160mm (axial length) × 35mm (minimum inner diameter) × 25mm (maximum relative arch height of the centering ridge frame 23), which can be adjusted according to the actual outer diameter of the anchor rod 1 steel bar and the inner diameter of the drill hole. The wall thickness of each part is generally 4mm.

[0070] The first snap door 212 and the second snap door 222 are formed integrally with the centering bracket 2. The first snap door 212 and the second snap door 222 are flat "U"-shaped frames with a thickness of 4 mm, and the net space inside the frame is 6 mm×12 mm (height×width), which serves as an occlusal channel for subsequent assembly of the first centering bracket flap 21 and the second centering bracket flap 22;

[0071] The first detent 211 and the second detent 221 are integrally formed with the centering bracket 2. The root of the detent (the connection with the centering bracket 2) is 8 mm wide, and gradually thickens to 12 mm along the 20° direction tangential to the circumference of the centering bracket 2. Then, a narrow slit about 3 mm wide is cut in the middle of the detent, and the detent is divided into two, forming a pair of small detents. The size of a single detent is 7 mm × 4 mm (width × height), and the aforementioned narrow slit is used as the space for pressing the pair of detents towards the middle.

[0072] The lashing channels 25 are provided at 10 mm - 20 mm from the left and right ends of the centering bracket 2, with a depth of 2 mm. The width can be appropriately increased on the basis of 3 mm to accommodate thick lashing ropes, etc.

[0073] Other parts not described belong to the prior art.

Claims

1. Multi-lobe, combinable bolt centering support device, characterized in that: It comprises an anchor rod (1) and a centering bracket (2) which wraps the anchor rod (1); The centering stent (2) comprises a first centering stent flap (21), a second centering stent flap (22) and a centering spine frame (23); The first pair of centering stent flaps (21) and the second pair of centering stent flaps (22) have the same structure. The first pair of centering stent flaps (21) and the second pair of centering stent flaps (22) wrap the anchor rod (1). The left and right ends of the first pair of centering stent flaps (21) and the second pair of centering stent flaps (22) are connected by a fixing device (3). The middle parts of the first pair of centering stent flaps (21) and the second pair of centering stent flaps (22) are each provided with two centering ridge frames (23). The fixing device (3) comprises a first buckle (211) located at the upper end of the first pair of centering support flaps (21), a first buckle door (212) located at the lower end of the first pair of centering support flaps (21), a second buckle door (222) located at the upper end of the second pair of centering support flaps (22), and a second buckle (221) located at the lower end of the second pair of centering support flaps (22); the first buckle (211) matches the second buckle door (222), and the first buckle door (212) matches the second buckle (221); A centering stent flap joint seam (24) is provided between the first centering stent flap (21) and the second centering stent flap (22); Both left and right ends of the first pair of central stent flaps (21) and the second pair of central stent flaps (22) are provided with binding grooves (25); the left and right ends of the first pair of central stent flaps (21) and the second pair of central stent flaps (22) form straight roads, and the structure of the middle part of the first pair of central stent flaps (21) and the second pair of central stent flaps (22) is that the left and right ends are concave and the middle part is arched; The first snap door (212) and the second snap door (222) are integrally formed with the centering bracket (2), and the first snap tooth (211) and the second snap tooth (221) are integrally formed with the centering bracket (2).

2. The multi-lobe, combinable anchor centering support device according to claim 1, characterized in that: The centering bracket (2) has a size of 160 mm×35 mm×25 mm, and a tube wall thickness of 4 mm.

3. The multi-lobe, combinable anchor centering support device according to claim 1, characterized in that: The first snap door (212) and the second snap door (222) are flat "U"-shaped frames with a thickness of 4 mm, and the net space inside the frames is 6 mm×12 mm, serving as an occlusal channel for the subsequent assembly of the first pair of centering stent flaps (21) and the second pair of centering stent flaps (22).

4. The multi-lobe, combinable anchor centering support device according to claim 3, characterized in that: The binding groove (25) is arranged at 10 mm to 20 mm on both ends of the centering bracket (2) and has a depth of 2 mm.

5. The construction method of the multi-lobe, combinable anchor centering support device according to any one of claims 1-4, characterized in that, The following steps are involved: Step 1: Confirm the position, direction, hole diameter and hole depth of the anchor rod (1) and start drilling; after the drilling is completed, extend the water pipe to the bottom of the hole and flush the hole with a large flow of water; Step 2: preparing anchor rods (1) of different lengths required for the anchoring project; Step 3: Customizing and processing the molds for the first pair of centering stent flaps (21) and the second pair of centering stent flaps (22), and carrying out standardized mass production in the workshop; Step 4: Preliminarily fit the first pair of center stent flaps (21) and the second pair of center stent flaps (22) relatively to each other on the anchor rod (1) along the center stent flap joint seam (24); Step 5: Press the first locking tooth (211) to merge it and then let it pass through the second locking door (222). After releasing the pressing force, the first locking tooth (211) naturally separates towards both sides and hooks on the second locking door (222); press the second locking tooth (221) to merge it and then let it pass through the first locking door (212). After releasing the pressing force, the second locking tooth (221) naturally separates towards both sides and hooks on the first locking door (212). Step 6: Use a wire or string to wind and firmly bind in the binding channels (25) at the left and right ends of the first pair of middle support petals (21) and the second pair of middle support petals (22), completing the installation and positioning of a single middle support (2) on the anchor rod (1). Step 7: Arrange and fix the grouting pipe and the exhaust pipe on the rod body of the anchor rod (1). Step 8: Send the entire anchor rod (1) into the drill hole, and push it manually. During the whole process, maintain a slow and uniform advancing speed to ensure that the materials of each part of the anchor rod (1) are not deformed or damaged due to extrusion and friction. Step 9: After the installation of the anchor rod (1) is completed, grout from the bottom through the grouting pipe hole. As the liquid level of the grout rises, discharge the residual gas in the drill hole through the exhaust pipe. Finally, when the grout reaches the hole opening, complete the hole sealing to finish the construction.

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