Pccp pipe inner layer concrete anti-cracking steel mesh limiting structure

Abstract

The utility model provides a kind of PCCP pipe inner layer concrete anti-cracking reinforcing mesh limiting structure, belong to PCCP pipe inner layer concrete anti-cracking reinforcing mesh technical field, this PCCP pipe inner layer concrete anti-cracking reinforcing mesh limiting structure includes fixed ring, limiting block and connecting rod, the fixed ring is circular ring structure, for installing on the inner wall of PCCP pipe, the inner circle surface of fixed ring is evenly distributed with several installation grooves along the circumference, every installation groove is dovetail groove shape, the limiting block is arranged in the installation groove;Can solve the existing PCCP pipe inner layer concrete pouring process, reinforcing mesh is easily under the action of concrete vibrating and cement paste flow due to lack of effective radial limiting fixing device and occurs radial displacement or deviation, leading to reinforcing mesh cannot be kept in design position, so that the steel distribution of inner layer concrete is uneven, weaken the anti-cracking performance and overall structural strength of concrete technical problem.

Description

Technical Field

[0001] This utility model belongs to the technical field of anti-crack steel mesh in the inner layer of PCCP pipe, specifically, it relates to a limiting structure for anti-crack steel mesh in the inner layer of PCCP pipe. Background Technology

[0002] Prestressed concrete cylinder pipe, or PCCP pipe, is widely used in urban water supply, long-distance water transmission, and industrial water transmission projects. PCCP pipe consists of an inner concrete layer, a steel cylinder, prestressed steel wires, and an outer concrete layer. The inner concrete layer is a crucial component, protecting the steel cylinder from water corrosion and providing a smooth inner wall. To enhance the crack resistance and structural strength of the inner concrete layer, steel mesh is typically incorporated as reinforcement. In current PCCP pipe manufacturing processes, the installation and fixing of the steel mesh mainly relies on manual positioning and temporary supports. After placing the steel mesh inside the pipe mold, construction workers temporarily fix it in the predetermined position using wire binding or supports before pouring concrete. This fixing method has significant technical drawbacks. Firstly, the steel mesh is easily subjected to vibration from concrete compaction and cement during concrete pouring. The impact force generated by the grout flow causes radial displacement or overall shift, preventing the reinforcing mesh from maintaining its designed position. Secondly, the existing temporary support methods lack sufficient fixing strength and cannot effectively resist various external forces during concrete pouring. Thirdly, the existing fixing methods lack adjustment functions and cannot adapt to the different requirements of PCCP pipes with different diameters and wall thicknesses for the position of the reinforcing mesh, resulting in low positioning accuracy and poor versatility of the reinforcing mesh. The displacement of the reinforcing mesh position leads to uneven distribution of reinforcing bars in the inner concrete layer, and insufficient reinforcing bar content in some areas weakens the crack resistance of the concrete, making it prone to cracking due to internal pressure or temperature changes during pipeline use, affecting the service life of PCCP pipes and water supply safety. Therefore, there is an urgent need to develop a PCCP pipe inner concrete reinforcing mesh limiting structure that can effectively fix the reinforcing mesh, has a position adjustment function, and is easy to install and operate. Utility Model Content

[0003] In view of this, the present invention provides a limiting structure for the anti-crack steel mesh in the inner layer of PCCP pipe concrete. This structure can solve the problem that during the pouring of the inner layer of concrete in existing PCCP pipes, the steel mesh is prone to radial displacement or offset under the action of concrete vibration and cement slurry flow due to the lack of an effective radial limiting and fixing device. This results in the steel mesh not being able to be kept in the designed position, causing uneven distribution of steel bars in the inner layer of concrete, weakening the crack resistance and overall structural strength of the concrete. At the same time, the existing fixing method has poor adjustability and cannot adapt to the installation requirements of steel mesh of different specifications, resulting in low positioning accuracy of the steel mesh and reduced construction efficiency.

[0004] This utility model is implemented as follows:

[0005] This utility model provides a limiting structure for the inner layer of concrete anti-crack reinforcing mesh in PCCP pipe, including a fixing ring, a limiting block, and a connecting rod. The fixing ring is annular and is used to install on the inner wall of the PCCP pipe. The inner surface of the fixing ring has several mounting grooves evenly distributed circumferentially, each mounting groove being dovetail-shaped. The limiting block is disposed in the mounting groove, and the limiting block and the mounting groove are slidably connected through the dovetail groove. The radial inner side of the limiting block is provided with a clamping groove, which is V-shaped. One end of the connecting rod is embedded in the clamping groove, and the connecting rod extends radially along the PCCP pipe. The other end of the connecting rod is provided with a pressing part, which is used to limit and fix the reinforcing mesh. The end face of the pressing part is serrated. The limiting block slides and adjusts its position in the radial direction of the PCCP pipe within the mounting groove.

[0006] The technical effects of the anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe provided by this utility model are as follows: A sliding connection is achieved by the dovetail groove-shaped installation groove evenly distributed circumferentially on the inner surface of the fixing ring and the dovetail groove of the limiting block. This allows the limiting block to flexibly adjust its position radially within the installation groove, thus adapting to the limiting requirements of steel mesh of different specifications. The V-shaped clamping groove on the radial inner side of the limiting block and the embedded part of one end of the connecting rod form a stable mechanical connection. The serrated end face of the pressing part at the other end of the connecting rod increases the frictional contact area with the steel mesh, effectively preventing displacement or shifting of the steel mesh during concrete pouring. This ensures accurate positioning of the steel mesh in the inner layer of PCCP pipe concrete and avoids concrete cracking caused by improper steel mesh positioning.

[0007] Based on the above technical solution, the present invention's PCCP pipe inner layer concrete anti-crack steel mesh limiting structure can be further improved as follows:

[0008] The outer surface of the fixing ring is provided with several radially extending reinforcing ribs, which are trapezoidal protrusions.

[0009] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the radially extending trapezoidal protrusions on the outer surface of the fixing ring increase the contact area and bonding strength between the fixing ring and the inner wall of the PCCP pipe. After the concrete is poured, the trapezoidal protrusions can form a mechanical interlocking effect with the concrete, which significantly improves the installation stability and pull-out resistance of the fixing ring on the inner wall of the PCCP pipe, and prevents the fixing ring from moving or falling off due to vibration or cement slurry impact during the concrete pouring process, thereby ensuring the reliability of the entire limiting structure and the positioning accuracy of the steel mesh.

[0010] Furthermore, the bottom of the mounting groove is provided with a limiting step, and the bottom of the limiting block is provided with a stepped surface that cooperates with the limiting step.

[0011] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the limiting step set at the bottom of the installation groove cooperates with the step surface at the bottom of the limiting block, providing a precise limiting positioning function when the limiting block slides and adjusts radially. The cooperation between the step surface and the limiting step can effectively limit the maximum sliding stroke of the limiting block, preventing the limiting block from completely falling out of the installation groove or sliding excessively. At the same time, the step structure increases the contact area between the limiting block and the installation groove, improving the stability and anti-overturning ability of the limiting block when subjected to the pressure of the steel mesh, and ensuring that the limiting force applied to the steel mesh by the connecting rod and the pressing part is always kept within a reasonable range.

[0012] Furthermore, the included angle between the two inclined surfaces of the clamping groove is 60~90°.

[0013] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the included angle between the two inclined surfaces of the clamping groove is set in the range of 60~90°. This angle range allows the connecting rod to form a self-locking effect when it is embedded in the clamping groove. When the connecting rod applies limiting pressure to the steel mesh, the reaction force of the steel mesh is transmitted to the inclined surface of the clamping groove through the connecting rod. The angle design of the inclined surface makes this reaction force convert into the outward component force of the limiting block and the downward clamping force. The clamping force further enhances the wedge-shaped engagement between the connecting rod and the clamping groove, preventing the connecting rod from loosening or slipping out of the clamping groove when subjected to external force, thus ensuring the long-term stability of the limiting structure.

[0014] Furthermore, the connecting rod has a rhomboid cross-section, and the connecting rod fits tightly against the inclined surface of the clamping groove.

[0015] The beneficial effects of adopting the above-mentioned improved scheme are as follows: The cross-section of the connecting rod adopts a rhomboid structure design. The four inclined surfaces of the rhombus and the two inclined surfaces of the V-shaped clamping groove achieve multi-point line contact and surface contact. Compared with the circular or square cross-section, the rhomboid cross-section can make fuller use of the V-shaped space of the clamping groove, increase the contact area and friction between the connecting rod and the clamping groove, and the symmetry of the rhomboid structure also makes the connecting rod have a self-centering effect when embedded in the clamping groove, ensuring that the connecting rod extends accurately along the radial direction of the PCCP pipe, avoiding the connecting rod from tilting or twisting, thereby ensuring that the limiting force applied by the pressing part to the steel mesh is evenly distributed.

[0016] Furthermore, the serrations on the end face of the pressing part are triangular, and a wedge-shaped recess is formed between two adjacent serrations.

[0017] The beneficial effects of the above-mentioned improvement scheme are as follows: the triangular toothed serration structure on the end face of the pressing part and the wedge-shaped recess formed between adjacent serrations work together to form a multi-point meshing contact between the pressing part and the surface of the reinforcing mesh. The tip of the triangular toothed serration can be embedded into the wire intersection or wire gap of the reinforcing mesh, while the wedge-shaped recess accommodates the wire portion of the reinforcing mesh. This structural design significantly improves the friction coefficient and anti-slip ability between the pressing part and the reinforcing mesh, effectively preventing the reinforcing mesh from shifting due to vibration or cement slurry flow during concrete pouring, and ensuring that the spatial position of the reinforcing mesh in the inner layer of concrete of the PCCP pipe remains stable.

[0018] Furthermore, the outer side of the limiting block is provided with an operating boss, which has a hemispherical structure and protrudes from the outer surface of the limiting block.

[0019] The beneficial effects of adopting the above-mentioned improved scheme are as follows: The hemispherical operating protrusion on the outer side of the limiting block provides a convenient gripping or pushing and pulling point for construction personnel when adjusting the position of the limiting block. The hemispherical structure has a smooth curved surface and protrudes from the outer surface of the limiting block. Construction personnel can easily apply radial pushing and pulling force by applying the operating protrusion with their fingers or tools, so that the limiting block can slide and adjust radially in the mounting groove. The hemispherical structure also avoids injury to the hands of construction personnel from sharp edges and corners. At the same time, the hemispherical protrusion can form a local reinforced area after the concrete is poured, which enhances the limiting block's ability to resist the lateral pressure of the concrete and improves the durability of the overall structure.

[0020] Furthermore, the number of mounting slots provided along the circumference of the fixing ring is 8 to 12, and the central angle between two adjacent mounting slots is equal.

[0021] The beneficial effects of adopting the above-mentioned improved scheme are as follows: The uniform distribution design of 8 to 12 installation slots along the circumference of the fixing ring with equal central angles between adjacent installation slots ensures that the limiting support force of the steel mesh is evenly distributed along the circumference of the PCCP pipe, avoiding local stress concentration. This uniformly distributed limiting structure can effectively balance the forces exerted on the steel mesh in various directions during concrete pouring, preventing local deformation or overall displacement of the steel mesh. The number of 8 to 12 slots ensures a sufficient number of limiting support points to achieve a stable limiting effect, while avoiding the problems of reduced structural strength of the fixing ring and complicated installation operations caused by too many installation slots.

[0022] Furthermore, the retaining ring is made of high-strength polypropylene, and the limiting block and the connecting rod are made of stainless steel.

[0023] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the fixing ring is made of high-strength polypropylene material, which has good toughness and corrosion resistance, and can resist the chemical erosion of alkaline environment and cement slurry in concrete. At the same time, the low density of polypropylene material reduces the overall weight of the limiting structure, which facilitates construction and installation. The limiting block and connecting rod are made of stainless steel material, which ensures that these load-bearing components have sufficient strength and rigidity. The high tensile strength and bending strength of stainless steel material enable the limiting block and connecting rod to withstand the pressure of steel mesh for a long time without plastic deformation or breakage. The corrosion resistance of stainless steel ensures the long service life of the limiting structure in the concrete environment.

[0024] Furthermore, the length of the connecting rod is 1 / 2 to 3 / 4 of the inner diameter of the fixing ring, and the sliding stroke of the limiting block in the mounting groove is 10mm to 30mm.

[0025] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the fixing ring is made of high-strength polypropylene material, which has good toughness and corrosion resistance, and can resist the chemical erosion of alkaline environment and cement slurry in concrete. At the same time, the low density of polypropylene material reduces the overall weight of the limiting structure, which facilitates construction and installation. The limiting block and connecting rod are made of stainless steel material, which ensures that these load-bearing components have sufficient strength and rigidity. The high tensile strength and bending strength of stainless steel material enable the limiting block and connecting rod to withstand the pressure of steel mesh for a long time without plastic deformation or breakage. The corrosion resistance of stainless steel ensures the long service life of the limiting structure in the concrete environment.

[0026] Compared with existing technologies, the beneficial effects of the anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe provided by this utility model are as follows: This utility model constructs a radially adjustable steel mesh limiting and fixing system through the combined design of a fixing ring, a limiting block, and a connecting rod. The dovetail groove-shaped mounting groove of the inner ring of the fixing ring and the sliding cooperation of the limiting block realize the radial position adjustment function of the limiting block, so that the limiting structure can adapt to steel meshes of different specifications and different installation positions. The V-shaped clamping groove of the limiting block and the diamond-shaped cross-section of the connecting rod cooperate to form a stable wedge-shaped self-locking connection. The sawtooth structure of the end pressing part of the connecting rod forms multi-point meshing contact with the steel mesh, which greatly improves the reliability and stability of the limiting and fixing, and effectively prevents the steel mesh from cracking. The steel mesh shifts during concrete pouring, ensuring accurate positioning of the steel mesh within the inner concrete layer of the PCCP pipe. This significantly improves the uniformity of steel reinforcement distribution in the inner concrete layer, enhancing the crack resistance and overall structural strength of the concrete. Furthermore, this invention features a simple structure and convenient operation. The radial sliding adjustment of the limiting block and the user-friendly design of the operating boss reduce construction difficulty and labor intensity, improving the production efficiency and product quality of PCCP pipes. The reinforcing ribs on the outer ring of the fixing ring enhance the bonding strength between the limiting structure and the pipe wall. The material selection balances corrosion resistance and load-bearing capacity, ensuring the long service life of the limiting structure. This invention provides an efficient and reliable steel mesh limiting and fixing technology solution for crack prevention construction of the inner concrete layer of PCCP pipes. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of a structural design for a concrete anti-crack steel mesh limiting structure for the inner layer of a PCCP pipe;

[0029] Figure 2 This is a schematic diagram of the fixed ring structure;

[0030] Figure 3 This is a schematic diagram of the connecting rod structure;

[0031] The attached diagram lists the components represented by each number as follows:

[0032] 1. Fixing ring; 2. Limiting block; 3. Connecting rod; 4. Pressing part. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0034] like Figure 1-3 The diagram shows a structural schematic of a limiting structure for the inner layer of concrete anti-crack steel mesh in a PCCP pipe provided by this utility model. The structure includes a fixing ring 1, a limiting block 2, and a connecting rod 3. The fixing ring is annular and is used to install on the inner wall of the PCCP pipe. Several mounting grooves are evenly distributed circumferentially on the inner surface of the fixing ring. Each mounting groove is dovetail-shaped. The limiting block is placed within the mounting groove, and the limiting block and the mounting groove are slidably connected through the dovetail groove. The radial inner side of the limiting block has a clamping groove with a V-shaped structure. One end of the connecting rod is embedded in the clamping groove and extends radially along the PCCP pipe. The other end of the connecting rod has a pressing part 4, which is used to limit and fix the steel mesh. The end face of the pressing part has a serrated structure. The limiting block slides and adjusts its position radially along the PCCP pipe within the mounting groove.

[0035] In the above technical solution, the outer surface of the fixing ring is provided with several radially extending reinforcing ribs, which are trapezoidal protrusions.

[0036] Furthermore, in the above technical solution, the bottom of the mounting groove is provided with a limiting step, and the bottom of the limiting block is provided with a stepped surface that cooperates with the limiting step.

[0037] Furthermore, in the above technical solution, the included angle between the two inclined surfaces of the clamping groove is 60~90°.

[0038] Furthermore, in the above technical solution, the cross-section of the connecting rod is rhomboid, and the connecting rod fits tightly against the inclined surface of the clamping groove.

[0039] Furthermore, in the above technical solution, the serrations on the end face of the pressing part are triangular in shape, and a wedge-shaped recess is formed between two adjacent serrations.

[0040] Furthermore, in the above technical solution, the outer side of the limiting block is provided with an operating boss, which has a hemispherical structure and protrudes from the outer surface of the limiting block.

[0041] Furthermore, in the above technical solution, the number of mounting grooves provided along the circumference of the fixing ring is 8 to 12, and the central angle between two adjacent mounting grooves is equal.

[0042] Furthermore, in the above technical solution, the fixing ring is made of high-strength polypropylene material, and the limiting block and connecting rod are made of stainless steel material.

[0043] Furthermore, in the above technical solution, the length of the connecting rod is 1 / 2 to 3 / 4 of the inner diameter of the fixed ring, and the sliding stroke of the limiting block in the mounting groove is 10mm to 30mm.

[0044] The following is a specific embodiment 1 of this utility model: This embodiment designs a steel mesh limiting structure for a PCCP pipe with an inner diameter of 2000mm and an inner concrete thickness of 50mm. The fixing ring is injection molded from high-strength polypropylene (PP) material. The fixing ring has an integral circular structure with an outer diameter of 2050mm, an inner diameter of 1980mm, a radial thickness of 35mm, and an axial width of 80mm. Ten trapezoidal raised reinforcing ribs are evenly distributed circumferentially on the outer surface of the fixing ring. Each reinforcing rib has a radial height of 8mm, an axial length of 60mm, a top width of 4mm, and a bottom width of 10mm. The reinforcing ribs extend radially in a trapezoidal cross-section, and the central angle between two adjacent reinforcing ribs is 36°. Ten mounting grooves are evenly distributed circumferentially on the inner surface of the fixing ring. Each mounting groove has a mounting groove with a diameter of 4mm and a bottom width of 10mm. The mounting groove is dovetail-shaped, with a groove opening width of 25mm, a groove bottom width of 35mm, and a groove depth of 20mm. The angle between the two side walls of the dovetail groove and the radial direction is 15°. The bottom of the mounting groove has a 3mm high limiting step, which is a ring-shaped protrusion located in the center of the groove bottom. The limiting block is made of 304 stainless steel sheet and is stamped. The overall dimensions of the limiting block are 40mm in length, 32mm in width, and 18mm in height. The side shape of the limiting block matches the cross-sectional shape of the dovetail groove. The bottom of the limiting block has a ring-shaped groove that matches the limiting step, with a groove depth of 3mm. The radial inner side of the limiting block has a V-shaped clamping groove with a depth of 12mm and a width of 15mm. The angle between the two inclined surfaces is 75°, and the angle between the inclined surfaces and the horizontal plane is 37°.The limit block has a 5° angle. A hemispherical operating boss with a diameter of 8mm is provided on the outer side of the limit block, protruding 5mm beyond the outer surface. The connecting rod is made of 316 stainless steel bar, with a total length of 750mm. The connecting rod has a rhomboid cross-section with diagonals of 14mm and 10mm. The four beveled surfaces of the rhomboid cross-section are smooth and flat. One end of the connecting rod is machined into a wedge-shaped structure to fit the clamping groove, with a wedge length of 15mm. The other end of the connecting rod is machined into a pressing part with a diameter of 20mm and a length of 30mm. The end face of the pressing part is machined with a serrated structure. The serrations are isosceles triangular teeth with a base length of 4mm and a height of 2mm. A wedge-shaped recess with a depth of 2mm is formed between two adjacent serrations. A total of 15 serrations are evenly distributed across the entire end face of the pressing part. During installation, the fixing ring is placed on the inner wall of a PCCP pipe mold with an inner diameter of 2000mm. The reinforcing ribs of the fixing ring are embedded in the pre-set positioning grooves on the inner wall of the pipe mold to achieve circumferential and axial fixation. Ten limiting blocks are inserted into ten installation slots respectively. According to the designed radial position of the reinforcing mesh, the limiting blocks are pushed to slide radially to... At a position 380mm from the inner wall of the pipe, align the wedge-shaped end of the connecting rod with the clamping groove and press it firmly in. The diamond-shaped cross-section of the connecting rod and the V-shaped clamping groove fit tightly together to form a wedge-shaped self-locking connection. Place a mesh made of 6mm diameter steel bars welded together inside the pipe mold. The radial position of the steel mesh is 380mm from the inner wall of the pipe, and the steel mesh size is 100mm by 100mm. Adjust the limiting blocks to ensure that the serrated end faces of the pressing parts of each connecting rod are in close contact with the surface of the steel mesh. The serrations embed into the steel bar intersections to form multi-point meshing and fixation. Then, proceed with the inner layer concrete pouring operation, using C4... For 0-strength grade fine aggregate concrete, the limiting structure continuously applies a stable limiting force to the reinforcing mesh during concrete vibration, effectively preventing radial or circumferential displacement of the mesh. After the concrete solidifies, the trapezoidal reinforcing ribs on the outer ring of the fixing ring form a strong mechanical interlock with the concrete. The entire limiting structure, along with the reinforcing mesh, is encased in the inner layer of concrete, becoming part of the PCCP pipe. The positional accuracy of the reinforcing mesh within the inner layer of concrete is controlled within ±2mm, and the reinforcing bars are evenly distributed in the inner layer, effectively improving the crack resistance of the inner layer and the overall structural strength.

[0045] The following is another specific embodiment 2 of this utility model: This embodiment is based on embodiment 1, and is optimized and improved for a PCCP pipe with an inner diameter of 2400mm and an inner concrete thickness of 60mm. The outer diameter of the fixing ring is adjusted to 2480mm, the inner diameter is adjusted to 2370mm, the radial thickness is increased to 40mm, and the axial width is maintained at 80mm. The number of installation grooves evenly distributed circumferentially on the inner ring of the fixing ring is increased to 12, and the central angle between two adjacent installation grooves is adjusted to 30° to meet the requirements of larger pipe diameters for the number of circumferential limiting points of the reinforcing mesh. The groove opening width is adjusted to 28mm, the groove bottom width is adjusted to 38mm, and the groove depth is maintained at 20mm. The external dimensions of the limiting block are adjusted accordingly to a length of 45mm, a width of 35mm, and a height of 18mm. The sliding stroke of the limiting block in the installation groove is increased to 25mm to meet the requirements of the radial position adjustment range of the reinforcing mesh under larger pipe diameter conditions. The total length of the connecting rod is increased to 880mm to accommodate the radial extension requirements of a 2400mm inner diameter pipe. The diagonal dimensions of the rhomboid cross-section of the connecting rod are adjusted to 16mm and 12mm to enhance its bending stiffness and load-bearing capacity. The diameter of the clamping part is enlarged to 25mm while the length remains at 30mm. The number of serrations on the end face of the clamping part is increased to 18, with the triangular base length of the serrations remaining at 4mm and the height increased to 2.5mm to enhance the meshing strength between the clamping part and the reinforcing mesh. In this embodiment, a reinforcing mesh is made by welding 8mm diameter steel bars, with a mesh size of 120mm x 120mm. The radial position of the reinforcing mesh is set at 450mm from the inner wall of the pipe. A circumferentially evenly distributed limiting support system is formed by 12 limiting blocks and connecting rods, effectively adapting to the limiting and fixing requirements of the reinforcing mesh for larger diameter PCCP pipes, ensuring the precise positioning and uniform distribution of the reinforcing mesh in the inner concrete layer.

[0046] The following is another specific embodiment 3 of this utility model: This embodiment is an improved design based on embodiment 1, specifically for the application scenario of configuring double-layer steel mesh in the inner concrete layer. The axial width of the fixing ring is increased to 120mm to accommodate the arrangement space of two rows of installation slots. Two rows of installation slots are arranged axially on the inner surface of the fixing ring, with 10 slots evenly distributed circumferentially in each row. The axial spacing between the two rows of installation slots is 50mm, and the two rows of installation slots are staggered by 18 degrees in the circumferential direction, forming a staggered limiting support layout. The structural parameters of each installation slot are consistent with those in embodiment 1. Each installation slot is equipped with a limiting block and a connecting rod to simultaneously limit and fix the inner and outer steel mesh layers. The radial position of the inner steel mesh layer is set to 320mm from the inner wall of the pipe, and the outer steel mesh layer… The radial position of the steel mesh is set at 380mm from the inner wall of the pipe, and the radial spacing between the inner and outer layers of steel mesh is 60mm. The inner layer of steel mesh is limited and fixed by the first row of limiting blocks and connecting rods, and the outer layer of steel mesh is limited and fixed by the second row of limiting blocks and connecting rods. The circumferential staggered arrangement of the two rows of limiting structures ensures that both the inner and outer layers of steel mesh receive circumferentially evenly distributed limiting support, effectively preventing relative displacement or overall shift of the double-layer steel mesh during concrete pouring. This embodiment is suitable for large-diameter high-pressure PCCP pipes with particularly high requirements for the crack resistance of the inner layer concrete. The double-layer steel mesh configuration combined with the adjustable limiting structure significantly improves the load-bearing capacity and crack resistance of the inner layer concrete, meeting the higher technical requirements of PCCP pipes for the crack resistance of the inner layer concrete under special working conditions.

[0047] Specifically, the principle of this utility model is as follows: This utility model uses a fixing ring as the basic support structure installed on the inner wall of the PCCP pipe. The dovetail-shaped mounting grooves evenly distributed circumferentially on the inner surface of the fixing ring provide a sliding guide channel for the limiting block. The trapezoidal cross-section structure of the dovetail groove allows the limiting block to remain stable and not dislodged while sliding radially within the mounting groove. This sliding engagement mechanism enables continuous adjustment of the radial position of the limiting block, allowing the limiting structure to adapt to the radial positioning requirements of different specifications of steel mesh. The V-shaped clamping groove on the radial inner side of the limiting block engages with one end of the connecting rod to form a wedge-shaped self-locking mechanism. The connection mechanism works as follows: when the connecting rod applies limiting pressure to the reinforcing mesh through the clamping part, the reaction force of the reinforcing mesh is transmitted to the inclined surface of the clamping groove through the connecting rod. Due to the reasonable design of the inclined angle of the V-shaped clamping groove, this reaction force is decomposed into a component force that makes the connecting rod press more tightly into the clamping groove, thus achieving a self-locking effect. The greater the external force borne by the connecting rod, the stronger the wedge-shaped engagement force between it and the clamping groove, effectively preventing the connecting rod from loosening or coming out when subjected to the pressure of the reinforcing mesh. The diamond-shaped cross-section design of the connecting rod further enhances this wedge-shaped fit effect. The four inclined surfaces of the diamond-shaped cross-section form multiple... Point contact increases the contact area and friction, improving the stability and load-bearing capacity of the connection. The retaining part at the other end of the connecting rod mechanically engages with the surface of the reinforcing mesh through a serrated structure on the end face. The tips of the serrations embed into the gaps or intersections of the steel wires in the reinforcing mesh, and the wedge-shaped recess accommodates the steel wire portion. This multi-point engagement contact method significantly improves the friction coefficient and anti-slip capability between the retaining part and the reinforcing mesh, effectively preventing the reinforcing mesh from shifting due to vibration or cement slurry impact during concrete pouring. The trapezoidal raised reinforcing ribs on the outer surface of the fixing ring mechanically engage with the concrete after pouring. The structure creates a hook-like anchoring effect after the concrete hardens, significantly improving the bonding strength and pull-out resistance between the fixing ring and the pipe wall, preventing the fixing ring from moving during concrete pouring. The limiting step at the bottom of the installation groove cooperates with the step surface at the bottom of the limiting block, providing precise stroke limit during the sliding adjustment of the limiting block, preventing the limiting block from sliding excessively or falling out of the installation groove. Through the synergistic effect of the above multiple technical principles, this utility model achieves reliable limiting and fixing and precise position adjustment of the steel mesh in the inner concrete layer of the PCCP pipe, effectively solving the technical problems of easy displacement and low positioning accuracy of the steel mesh in the prior art.

[0048] During the construction preparation stage, select the appropriate fixing ring according to the inner diameter of the PCCP pipe. Install the fixing ring at the predetermined position on the inner wall of the pipe mold. The circumferential positioning and axial fixation of the fixing ring are achieved by the cooperation of the reinforcing ribs on the outer ring of the fixing ring with the positioning holes or grooves on the inner wall of the pipe mold. Check that the mounting groove of the inner ring of the fixing ring is clean and free of debris. Insert the limiting block into the mounting groove and confirm that the limiting block can slide smoothly within the mounting groove. According to the radial position requirements of the steel mesh to be installed, adjust the radial position of the limiting block in the mounting groove by pushing and pulling the operating boss on the outer side of the limiting block, so that the limiting block reaches the predetermined radial coordinate point. Select a connecting rod that matches the clamping groove of the limiting block. Align one end of the rhomboid section of the connecting rod with the V-shaped opening of the clamping groove and press it in radially to embed the connecting rod into the clamping groove. Confirm that the connecting rod and the clamping groove form a stable wedge fit. Place the pre-made steel mesh inside the pipe mold, so that the steel mesh... The radial position of the reinforcing mesh corresponds to the pressing part of the connecting rod. By finely adjusting the radial position of the limiting block, the serrated end face of the pressing part is made to make close contact with the surface of the reinforcing mesh. Repeat the above operation to install the limiting block and connecting rod at other mounting slot positions of the fixing ring, forming a multi-point circumferential limiting support for the reinforcing mesh. Check whether the pressing parts of all connecting rods maintain good contact with the reinforcing mesh, and confirm that the reinforcing mesh is effectively limited and fixed in all directions. Then, carry out the inner layer concrete pouring operation. During the concrete pouring and vibration process, the limiting structure continuously applies a limiting effect to the reinforcing mesh to prevent displacement. After the concrete initially sets, the entire limiting structure and the reinforcing mesh are wrapped in the inner layer concrete, becoming part of the inner layer structure of the PCCP pipe. The operation method of this utility model is simple and quick, requires no special tools, and ordinary construction personnel can operate it proficiently after simple training, which significantly improves the production efficiency of PCCP pipes.

Claims

1. A limiting structure for the inner layer of concrete anti-crack reinforcing mesh in a PCCP pipe, comprising a fixing ring, a limiting block, and a connecting rod, wherein the fixing ring is annular and is used for installation on the inner wall of the PCCP pipe; the inner surface of the fixing ring has a plurality of mounting grooves evenly distributed circumferentially, each mounting groove being dovetail-shaped; the limiting block is disposed within the mounting groove; and the limiting block and the mounting groove are slidably connected through the dovetail groove engagement, characterized in that... The limiting block has a clamping groove on its radial inner side. The clamping groove has a V-shaped structure. One end of the connecting rod is embedded in the clamping groove. The connecting rod extends radially along the PCCP pipe. The other end of the connecting rod has a pressing part. The pressing part is used to limit and fix the steel mesh. The end face of the pressing part has a serrated structure. The limiting block slides and adjusts its position in the mounting groove along the radial direction of the PCCP pipe.

2. The anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe concrete according to claim 1, characterized in that, The outer surface of the fixing ring is provided with several radially extending reinforcing ribs, which are trapezoidal protrusions.

3. The anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe according to claim 2, characterized in that, The bottom of the mounting groove is provided with a limiting step, and the bottom of the limiting block is provided with a stepped surface that cooperates with the limiting step.

4. The anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe concrete according to claim 3, characterized in that, The included angle between the two inclined surfaces of the clamping groove is 60~90°.

5. The anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe concrete according to claim 4, characterized in that, The connecting rod has a rhomboid cross-section and fits tightly against the inclined surface of the clamping groove.

6. The anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe concrete according to claim 5, characterized in that, The serrations on the end face of the pressing part are triangular, and a wedge-shaped recess is formed between two adjacent serrations.

7. The anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe concrete according to claim 6, characterized in that, The outer side of the limiting block is provided with an operating boss, which has a hemispherical structure and protrudes from the outer surface of the limiting block.

8. The anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe according to claim 7, characterized in that, The number of mounting slots provided along the circumference of the fixing ring is 8 to 12, and the central angle between two adjacent mounting slots is equal.

9. The anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe concrete according to claim 8, characterized in that, The retaining ring is made of high-strength polypropylene, and the limiting block and the connecting rod are made of stainless steel.

10. The anti-cracking steel mesh limiting structure for the inner layer of PCCP pipe according to claim 9, characterized in that, The length of the connecting rod is 1 / 2 to 3 / 4 of the inner diameter of the fixing ring, and the sliding stroke of the limiting block in the mounting groove is 10mm to 30mm.

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