A structural combination design optimization method for cement pavement repair

Abstract

The application discloses a cement pavement repairing structure combination design optimization method, relates to the technical field of highway engineering concrete pavement damage maintenance and repair, and is characterized in that: the convex pit groove repairing structure is arranged, on the basis of improving the interlayer contact state of the area outside the joint of the new and old concrete panels, under the coupling effect of heavy load and environment, the stress characteristics of the joint area of the new and old panels of the cement pavement are effectively improved, when cracks are generated at the surface layer or the joint, the waterproof film layer in the composite isolation layer prevents water from flowing into the base layer, prevents the pumping and mud pumping phenomenon of the pavement panel under the action of the driving load, meanwhile, the composite isolation layer form is arranged between the surface layer and the base layer, the interlayer contact state of the surface layer and the semi-rigid or rigid base layer is improved, the surface layer and the base layer are vertically and continuously and smoothly contacted, and when the concrete panel bears the load, the overall stress uniformly disperses the external load to the base layer.

Description

Technical Field

[0001] This invention relates to the field of maintenance and repair technology for damaged concrete pavement in highway engineering, specifically a structural combination design optimization method for cement pavement repair. Background Technology

[0002] The current method for repairing concrete pavements mainly involves marking and cutting, chiseling away the damaged concrete, and then pouring repair concrete. This method does not address the contact between the concrete pavement and the subgrade in the repair area, nor does it treat the joints between the old and new concrete panels. This approach does not conform to the design theory of thin plates with small deflection on elastic half-space foundations for cement concrete pavements in my country. This theory assumes that the surface layer and the base layer have a vertically continuous and smooth contact, meaning that the contact surfaces of the panel and the base layer always match during deformation, the vertical displacements of the panel and the base layer are equal, and there is no frictional resistance on the contact surfaces of the panel and the base layer.

[0003] Currently, during the repair and paving of cement concrete pavements, cement slurry seeps into the base layer through cracks, forming a weak transition layer between the base and the surface layer. This transition layer creates high friction between the base and the cement concrete surface layer. The bottom of the joint between the old and new concrete is a particularly weak area. Under repeated heavy traffic loads, and under the influence of warping or shrinkage stress caused by temperature or humidity gradients, stress concentration occurs. The bottom of the slab experiences tensile stress, leading to cracks. The moment the crack penetrates the slab thickness, the tensile stress near the crack ends is completely released, like a taut spring suddenly snapping. This results in a huge restoring force that causes the surface layer to shrink back. This sudden restoring force is very large. Because the transition layer bonds the surface layer and base layer together, the base layer prevents this restoring movement. This inevitably generates a huge shear force near the interface. The shear force quickly causes a horizontal crack to form at the interface between the surface layer and the base layer. This crack then causes the surface layer to separate from the base layer along the transition layer, creating a separation interface.

[0004] After the interlayer transition layer breaks down, the broken layer will expand unevenly, exacerbating uneven voids in the pavement and reducing the pavement's load-bearing capacity. Water enters the interface between the surface layer and the base layer along the pavement joints or cracks, and under the impact of vehicle loads, it will cause the broken layer to be eroded and voided, further deteriorating the contact between the surface layer and the base layer. This accelerates the damage rate of the cement concrete pavement repair structure, resulting in a shorter service life and poor repair effect. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that cement concrete pavement repair structures in the prior art are prone to secondary damage.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a structural combination design optimization method for cement pavement repair, characterized in that the method includes:

[0008] The road repair structure assembly includes a convex pothole, a base course, a composite isolation layer consisting of multiple layers of geotextile and a waterproof membrane, a mortar leveling layer, reinforcing bars, dowel bars, a grouting layer, embedded pressure cells, and a concrete surface layer, wherein:

[0009] a. A convex pothole consists of the removal of damaged concrete pavement and the removal of the base layer in the part to be repaired. The area of ​​the base layer to be repaired is larger than the area of ​​the damaged surface layer to be removed. The boundary of the base layer to be repaired extends beyond the upper cutting line and forms a cavity with the bottom of the original surface layer.

[0010] b. After the top surface of the base layer is partially removed and a rough surface is exposed, mortar is used to level the rough top surface of the base layer and form a leveling layer;

[0011] c. A composite isolation layer consisting of multiple geotextile layers and a waterproof membrane layer is located on the leveling layer inside the convex pit;

[0012] d. The force transmission rod adopts a U-shaped force transmission rod, which is matched with the reinforcing rib. When installing the U-shaped force transmission rod-reinforcing rib composite structure, the force transmission rod functional end of the force transmission rod-reinforcing rib is inserted into the drill hole, and the reinforcing rib functional end is inserted into the cavity. The force transmission rod-reinforcing rib composite structure is arranged longitudinally in the direction of travel. The reinforcement is appropriately densified at the corners on both sides of the repair structure, and the transverse reinforcing ribs are welded to form an integral structure.

[0013] e. The grouting layer is composed of elastic grouting bags with the same size as the cavity. Two connection holes A and two connection holes B are opened on the side of the grouting bag near the reinforcing rib. Small mesh pipes are arranged on the outer surface of the elastic grouting bag. Small mesh pipes are provided with evenly distributed small holes. The mesh pipes are in a grid structure and are evenly distributed on the surface of the elastic grouting bag.

[0014] Optimize repair and construction methods, including:

[0015] Step 1: Determine the construction boundary and cut and remove the damaged old cement concrete pavement;

[0016] Step 2: Compact and level the top surface of the roadbed;

[0017] Step 3: Pre-embedding the pressure box;

[0018] Step 4: Laying the isolation layer;

[0019] Step 5: Install reinforcing ribs and force transmission rods;

[0020] Step 6: Laying the grouting layer;

[0021] Step 7: Pour the repair material.

[0022] The present invention is further configured such that: in the step of cutting and breaking up the damaged old cement concrete pavement, the cavity formed by the base layer boundary and the bottom of the original surface layer of the part to be repaired is chiseled out in the driving direction, with a length greater than 0.5m and less than 1m and a height greater than 5cm and less than 20cm.

[0023] The present invention is further configured such that: in the pressure box pre-embedding step, a pre-embedded pressure box is arranged at the center of the repair area and at the top surface of the base layer, and a pre-embedded pressure box is arranged at the two sides of the corner of the repair area and at the top surface of the base layer respectively. The pressure boxes are located under the composite isolation layer and on the top surface of the base layer; correspondingly, in the cavity area, pre-embedded pressure boxes are arranged at the center of the top surface of the cavity and at the two corners near the repair joint.

[0024] The present invention is further configured such that: in the isolation layer laying step, the multi-layer geotextile layer is specifically two layers, the first layer of geotextile is located on the leveling layer, the waterproof membrane layer is located on the first layer of geotextile, and the second layer of geotextile is located on the waterproof membrane layer. The two layers of geotextile and the one layer of waterproof membrane form a composite isolation layer sandwich structure. The boundary of the composite isolation layer is bonded. The composite isolation layer composed of the multi-layer geotextile layer and the waterproof membrane layer is located on the leveling layer in the convex pit. The laying area is equal to the area of ​​the removed part of the roadbed. One end extends into the cavity formed by the original concrete pavement and the removed part of the base layer and is tightly attached to one side of the base layer.

[0025] The present invention is further configured as follows: in the installation step of the reinforcing bar-reinforcing bar, after the composite isolation layer is laid in the cavity, a hole is drilled on one side of the original concrete pavement cut surface, and the U-shaped reinforcing bar-reinforcing bar composite structure is installed. The functional end of the reinforcing bar-reinforcing bar is inserted into the drilled hole, and the functional end of the reinforcing bar is inserted into the cavity. The reinforcing bar-reinforcing bar composite structure is arranged longitudinally in the driving direction, and the corners on both sides of the repair structure are appropriately densified. The transverse reinforcing bars are welded to form an integral structure.

[0026] The present invention is further configured such that: in the grouting layer laying step, specifically, firstly, one end of the L-shaped grouting pipe outlet is connected to an elastic grouting bag, and interface A and interface B are connected respectively. The elastic grouting bag is placed in the cavity area, located on the composite isolation layer and the reinforcing rib, with the other end of the grouting outlet facing upward and higher than the original road surface elevation.

[0027] The invention is further configured as follows: In the grouting layer laying step, the isolation layer of the repair area is leveled and the surface scum of the joint is cleaned. Before concrete pouring, the elastic grouting bag is pre-inflated through interface A. There are two elastic grouting interfaces A. The valve of one grouting port A is closed, and the other grouting port A is inflated so that the bag supports the cavity area. The valve of the connection port is closed. Similarly, there are connection ports B reserved at both ends of the grouting bag for connecting the mesh pipe. The grouting material is injected into the grouting bag through connection port A for filling, and the grouting material is injected into the mesh grouting pipe through connection port B and released through evenly distributed small holes.

[0028] The present invention is further configured as follows: In the repair material pouring step, the repair material is poured within the remaining construction area. The repair material is a micro-expansion high crack-resistant cement-based rapid repair material. After the repair material hardens, preliminary grouting is performed in the cavity area based on the measured pressure of the pressure box in the central area and the corner area. The preliminary grouting is grouting into the elastic grouting bag. One of the two grouting ports A with all the interface valves closed is opened, while the other is kept closed. Pressurized grouting is performed by opening the grouting port A. The grouting pressure is greater than the measured pressure of the pre-embedded pressure box in the repair area, but not exceeding 10%. When the grouting is almost completed, the grouting pressure is maintained. The grouting pressure is held, and the pressure measured by the pressure box in the cavity area is observed. If the measured pressure is stable and there is no significant change, the pressure is held for another 2 minutes, and the grouting port valve is closed to prevent the pressure from dropping.

[0029] The present invention is further configured as follows: In the repair material pouring step, after the initial grouting material has hardened, the pressure of the pressure box in the cavity area is continuously observed. If the pressure box pressure drops and the drop area is stable without significant change, secondary grouting is performed through grouting port B. The grouting monitoring process is the same as the initial grouting. When the grouting is almost completed, the grouting pressure is maintained. The grouting pressure is held, and the pressure measured by the pressure box in the cavity area is observed. If the measured pressure is stable without significant change, the pressure is held for another 2 minutes, and then the grouting port valve is closed.

[0030] Compared with known public technologies, the technical solution provided by this invention has the following beneficial effects:

[0031] This invention, by setting a convex pothole repair structure, improves the interlayer contact state in areas other than the joint between new and old concrete panels. Under heavy load and environmental coupling, it effectively improves the stress characteristics of the joint area between new and old concrete pavement panels. Compared with conventional concrete pavement pothole repair, by extending the laying length of the composite isolation layer, when concentrated vehicle loads are applied to the joint, the new and old panels work together, and the reinforcing ribs at the bottom of the panel and the composite isolation layer effectively disperse stress, reducing the bending tensile stress at the bottom of the panel and effectively improving the stress concentration phenomenon.

[0032] This invention, by setting a double-layer geotextile sandwiched with a waterproof membrane layer, prevents water from flowing into the base layer when cracks occur in the surface layer or at the joints. It also prevents the road slab from pumping or squeezing under traffic loads, thereby preventing misalignment and detachment at the joints, extending the service life of the cement concrete pavement repair structure, effectively solving the defect of poor resistance to gravel or sharp objects in the waterproof layer, and ensuring the integrity of the geomembrane below the road surface.

[0033] This invention incorporates a composite isolation layer between the surface layer and the base layer to improve the interlayer contact between the surface layer and the semi-rigid or rigid base layer. The surface layer and the base layer have a vertically continuous and smooth contact. When the concrete panel bears a load, the overall force evenly distributes the external load to the base layer, thereby solving the problem of secondary damage to cement concrete pavement repair structures in the prior art. Attached Figure Description

[0034] Figure 1 This is an optimized construction flowchart of a structural combination design optimization method for cement pavement repair according to the present invention;

[0035] Figure 2 This invention provides a structural design optimization method for cement pavement repair using a convex pothole structure diagram.

[0036] Figure 3 This invention provides a structural design optimization method for repairing cement pavements, including a convex pothole with a side cavity structure at the bottom.

[0037] Figure 4 This is a schematic diagram of the structural combination design optimization method for cement pavement repair according to the present invention, including geotextile, waterproof membrane, grouting pipe, and U-shaped reinforcing bar-dowel bar positions.

[0038] Figure 5 This is a schematic diagram of the reinforcing bar-dowel bar installation and connection structure of a structural combination design optimization method for cement pavement repair according to the present invention;

[0039] Figure 6 This is a schematic diagram of an elastic grouting bag structure for a structural combination design optimization method for cement pavement repair according to the present invention.

[0040] Figure 7 This is a diagram showing the installation position of the pressure box in a structural combination design optimization method for cement pavement repair according to the present invention.

[0041] Figure 8 This is a schematic diagram of the external mesh pipeline structure of an elastic grouting bag in a structural combination design optimization method for cement pavement repair according to the present invention. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Please see Figures 1-8 This invention provides a technical solution: a structural combination design optimization method for cement pavement repair, characterized in that the method includes:

[0044] The road repair structure assembly includes a convex pothole, a base course, a composite isolation layer consisting of multiple layers of geotextile and a waterproof membrane, a mortar leveling layer, reinforcing bars, dowel bars, a grouting layer, embedded pressure cells, and a concrete surface layer, wherein:

[0045] a. A convex pothole consists of removing the damaged concrete pavement and removing the base layer of the area to be repaired. The area of ​​the base layer removed for repair is larger than the area of ​​the damaged surface layer removed. The boundary of the base layer removed for repair extends beyond the upper cutting line and forms a cavity with the bottom of the original surface layer. Figure 2 As shown;

[0046] b. After the top surface of the base layer is partially removed and a rough surface is exposed, mortar is used to level the rough top surface of the base layer and form a leveling layer;

[0047] c. A composite isolation layer consisting of multiple geotextile layers and a waterproof membrane layer is located on the leveling layer inside the convex pit;

[0048] d. The force transmission rod adopts a U-shaped force transmission rod, which cooperates with the reinforcing rib. During the installation of the U-shaped force transmission rod-reinforcing rib composite structure, the functional end of the force transmission rod is inserted into the drilled hole, and the functional end of the reinforcing rib is inserted into the cavity. The force transmission rod-reinforcing rib composite structure is arranged longitudinally in the direction of travel. The force transmission rod is appropriately densified at the corners on both sides of the repair structure. The transverse reinforcing ribs are welded to form an integral structure, such as... Figure 5 As shown, end A is poured into the newly repaired concrete, end B is inserted into the original pavement concrete through drilling, and end C is inserted into the cavity and located on the composite isolation layer.

[0049] e. The grouting layer consists of elastic grouting bags, the size of which matches the cavity size. Two connection holes A and two connection holes B are opened on the side of the grouting bag near the reinforcing rib. Small mesh pipes are arranged on the outer surface of the elastic grouting bag, with evenly distributed small holes on these pipes. The mesh pipes form a grid structure and are evenly distributed on the surface of the elastic grouting bag. Figure 6 As shown.

[0050] Optimize repair and construction methods, including:

[0051] S1. First, the damaged old cement concrete pavement is cut and demolished to determine the construction boundaries for repair. The damaged pavement is then excavated to a depth equal to the original concrete pavement slab thickness, reaching the top of the roadbed. Further, a portion of the roadbed is excavated to a depth greater than 5cm but less than 20cm. Figure 3 As shown;

[0052] S2. The top surface of the excavated roadbed is re-compacted using small compaction equipment, with the compaction standard being the same as that of the original concrete pavement roadbed. After compaction, the top surface of the excavated roadbed, including any voids, is leveled with mortar. Figure 4 As shown;

[0053] S3. After leveling is completed, embedded pressure boxes are placed in different locations. One embedded pressure box is placed at the center of the repair area and on the top surface of the base layer. Two embedded pressure boxes are placed at the two corners of the repair area and on the top surface of the base layer. The pressure boxes are located below the composite isolation layer and on the top surface of the base layer. Correspondingly, in the cavity area, embedded pressure boxes are placed at the center of the cavity top surface and at the two corners near the repair joint. Figure 7 As shown;

[0054] S4. Lay a composite isolation layer. The composite isolation layer, which is composed of multiple layers of geotextile and waterproof membrane, is located on the leveling layer in the convex pit. The laying area is equal to the area of ​​the removed subgrade. One end extends into the cavity between the original concrete pavement and the removed base layer and is close to the base layer.

[0055] S5. After the composite isolation layer is laid on the top surface of the roadbed leveling layer and the cavity, a hole is drilled on one side of the original concrete pavement cut surface, and the U-shaped dowel bar-reinforcing rib composite structure is installed. The dowel bar functional end of the dowel bar-reinforcing rib is inserted into the drilled hole, and the reinforcing rib functional end is inserted into the cavity. The dowel bar-reinforcing rib composite structure is arranged longitudinally in the driving direction. The two sides of the repair structure are appropriately densified, and the transverse reinforcing ribs are welded to form an integral structure.

[0056] S6. After the installation of the dowel bar-reinforcing rib composite structure is completed, connect one end of the L-shaped grouting pipe to the elastic grouting bag, connect interface A and interface B respectively, place the elastic grouting bag into the cavity area, located on the composite isolation layer and reinforcing rib, with the other end of the grouting port facing upward and higher than the original road surface elevation.

[0057] S7. Level and repair the isolation layer of the area and clean the surface scum of the joint to keep it clean and tidy. Before pouring concrete, pre-inflate the elastic grouting bag through interface A. There are two elastic grouting interfaces A. Close the valve of one grouting port A and inflate the other grouting port A with air so that the bag supports the cavity area. Close the valve of the connection port.

[0058] S8. After completion, based on the repair material mix ratio and the original concrete pavement slab's length, width, and thickness, cast precast slabs of the same size and mix ratio in an open area. These precast slabs are used to determine the grouting pressure; only one slab needs to be prepared. The precast slab, hardened to the corresponding strength grade, is hoisted to the repair area. After leveling, the pressure from the pressure cells embedded in the top surface of the roadbed and at the corners is collected. After pressure collection, the precast slab is removed. This step only needs to be performed once; the obtained grouting pressure can be used in subsequent sections and at different station numbers, and the precast pressure cells in the repair area do not need to be re-installed.

[0059] S9. Pour repair material within the remaining construction area. The repair material is a micro-expansion, high-crack-resistant cement-based rapid repair material. After the repair material hardens, perform preliminary grouting in the cavity area based on the measured pressure of the pressure boxes in the central and corner areas. Preliminary grouting involves injecting grout into the elastic grouting bag. Open one of the two grouting ports A with all interface valves closed, while keeping the other closed. Pressurize the grouting by opening valve A. The grouting pressure should be greater than the measured pressure of the pre-embedded pressure box in the repair area, but not exceeding 10%. When the grouting is nearly complete, maintain the grouting pressure. Observe the pressure measured by the pressure box in the cavity area. If the measured pressure is stable and shows no significant change, continue to maintain the pressure for 2 minutes, then close the grouting port valve to prevent pressure drop.

[0060] S10. Based on the characteristics of the grouting material, after the initial grouting material has hardened, continue to monitor the pressure of the pressure box in the cavity area. If the pressure box pressure drops and the drop area is stable without significant changes, perform secondary grouting through grouting port B. The grouting monitoring process is the same as the initial grouting. When the grouting is almost complete, maintain the grouting pressure and observe the pressure measured by the pressure box in the cavity area. If the measured pressure is stable without significant changes, continue to maintain the pressure for 2 minutes and then close the grouting port valve.

[0061] In summary, the structural combination design optimization method for cement pavement repair provided by this invention effectively improves the stress characteristics of the joint area between new and old cement pavement slabs by setting a convex pothole repair structure. The load transfer mechanism between the new and old slabs of the cement pavement repair is effectively improved. Compared with conventional concrete pavement pothole repair, by extending the laying length of the composite isolation layer, when concentrated vehicle loads are applied to the joint, the new and old panels work together, and the reinforcing bars at the bottom of the slab and the composite isolation layer effectively disperse stress, reducing the bending tensile stress at the bottom of the slab and effectively improving the stress concentration phenomenon. In addition, by setting the composite isolation layer and using a double-layer geotextile sandwiched with a waterproof membrane layer, the defect of poor resistance to gravel or sharp object puncture of the waterproof layer is effectively solved, ensuring the integrity of the geomembrane below the pavement. Meanwhile, when cracks occur in the surface layer or at the joints, the waterproof membrane layer in the composite isolation layer prevents water from flowing into the base layer, thereby preventing pumping and mud pumping of the pavement slab under traffic loads. This also prevents misalignment and detachment of the slab at the joints, extending the service life of the cement concrete pavement repair structure. Furthermore, the composite isolation layer between the surface layer and the base layer improves the interlayer contact between the surface layer and the semi-rigid or rigid base layer. The surface layer and the base layer have a vertically continuous and smooth contact. When the concrete slab bears the load, the overall force evenly distributes the external load to the base layer.

[0062] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A structural combination design optimization method for cement pavement repair, characterized in that, The method includes: The road repair structure assembly includes a convex pothole, a base course, a composite isolation layer consisting of multiple layers of geotextile and a waterproof membrane, a mortar leveling layer, reinforcing bars, dowel bars, a grouting layer, embedded pressure cells, and a concrete surface layer, wherein: a. A convex pothole consists of the removal of damaged concrete pavement and the removal of the base layer in the part to be repaired. The area of ​​the base layer to be repaired is larger than the area of ​​the damaged surface layer to be removed. The boundary of the base layer to be repaired extends beyond the upper cutting line and forms a cavity with the bottom of the original surface layer. b. After the top surface of the base layer is partially removed and a rough surface is exposed, mortar is used to level the rough top surface of the base layer and form a leveling layer; c. A composite isolation layer consisting of multiple geotextile layers and a waterproof membrane layer is located on the leveling layer inside the convex pit; d. The dowel bars adopt U-shaped dowel bars, which are used in conjunction with the reinforcing bars. When installing the U-shaped dowel bar-reinforcing bar composite structure, a hole is drilled on one side of the cut surface of the original concrete pavement. The functional end of the dowel bar-reinforcing bar is inserted into the drilled hole, and the functional end of the reinforcing bar is inserted into the cavity. The dowel bar-reinforcing bar composite structure is arranged longitudinally in the direction of travel. The dowel bars are appropriately densified at the corners on both sides of the repair structure. The transverse reinforcing bars are welded to form an integral structure. e. The grouting layer is composed of elastic grouting bags. The size of the grouting bags is the same as the size of the cavity. Two connection holes A and two connection holes B are opened on the side of the grouting bag near the reinforcing rib. Small mesh pipes are arranged on the outer surface of the elastic grouting bag. Small holes are evenly distributed on the small mesh pipes. The mesh pipes are in a grid structure and are evenly distributed on the surface of the elastic grouting bag. Optimize repair and construction methods, including: Step 1: Determine the construction boundary and cut and remove the damaged old cement concrete pavement; Step 2: Compact and level the top surface of the roadbed; Step 3: Pre-embedding the pressure box; Step 4: Laying the isolation layer; Step 5: Install reinforcing ribs and force transmission rods; Step 6: Laying the grouting layer; Step 7: Pour the repair material; In the repair material pouring step, the repair material is poured within the remaining construction area. The repair material is a micro-expansion high crack-resistant cement-based rapid repair material. After the repair material hardens, preliminary grouting is performed in the cavity area based on the measured pressure of the pressure box in the central area and the corner area. Preliminary grouting involves injecting grout into the elastic grouting bag. One of the two grouting ports A with all the interface valves closed is opened while the other remains closed. Pressurized grouting is performed by opening the grouting port A. The grouting pressure is greater than the measured pressure of the pre-embedded pressure box in the repair area, but not exceeding 10%. When the grouting is almost complete, the grouting pressure is maintained. The pressure is held while the pressure measured by the pressure box in the cavity area is observed. If the measured pressure is stable and does not change significantly, the pressure is held for another 2 minutes. Then, the grouting port valve is closed to prevent the pressure from dropping. In the repair material pouring step, after the initial grouting material has hardened, the pressure of the pressure box in the cavity area is continuously monitored. If the pressure box pressure drops and the drop area is stable without significant change, secondary grouting is performed through grouting port B. The grouting monitoring process is the same as the initial grouting. When the grouting is almost complete, the grouting pressure is maintained. The grouting pressure is held, and the pressure measured by the pressure box in the cavity area is observed. If the measured pressure is stable without significant change, the pressure is held for another 2 minutes, and then the grouting port valve is closed.

2. The structural combination design optimization method for cement pavement repair according to claim 1, characterized in that, The construction boundary is defined. In the step of cutting and breaking up the damaged old cement concrete pavement, the cavity formed by the base layer boundary and the bottom of the original surface layer in the part to be repaired is greater than 0.5m and less than 1m in length and greater than 5cm and less than 20cm in height in the direction of travel.

3. The structural combination design optimization method for cement pavement repair according to claim 1, characterized in that, In the pressure box pre-embedding step, a pre-embedded pressure box is arranged at the center of the repair area and on the top surface of the base layer, and a pre-embedded pressure box is arranged at the two corners of the repair area and on the top surface of the base layer. The pressure boxes are located under the composite isolation layer and on the top surface of the base layer. Correspondingly, in the cavity area, pre-embedded pressure boxes are arranged at the center of the top surface of the cavity and at the two corners near the repair joint.

4. The structural combination design optimization method for cement pavement repair according to claim 1, characterized in that, In the isolation layer laying step, the multi-layer geotextile layer specifically consists of two layers. The first layer of geotextile is located on the leveling layer, the waterproof membrane layer is located on the first layer of geotextile, and the second layer of geotextile is located on the waterproof membrane layer. The two layers of geotextile and the waterproof membrane form a composite isolation layer sandwich structure. The boundary of the composite isolation layer is bonded. The composite isolation layer composed of the multi-layer geotextile and the waterproof membrane layer is located on the leveling layer in the convex pit. The laying area is equal to the area of ​​the removed part of the roadbed. One end extends into the cavity formed by the original concrete pavement and the removed part of the base layer and is tightly attached to one side of the base layer.

5. The structural combination design optimization method for cement pavement repair according to claim 1, characterized in that, In the installation steps of the reinforcing bar-reinforcing bar, after the composite isolation layer is laid in the cavity, a hole is drilled on one side of the original concrete pavement cut surface, and the U-shaped reinforcing bar-reinforcing bar composite structure is installed. The functional end of the reinforcing bar-reinforcing bar is inserted into the drilled hole, and the functional end of the reinforcing bar is inserted into the cavity. The reinforcing bar-reinforcing bar composite structure is arranged longitudinally in the driving direction, and the corners on both sides of the repair structure are appropriately densified. The transverse reinforcing bars are welded to form an integral structure.

6. The structural combination design optimization method for cement pavement repair according to claim 1, characterized in that, In the grouting layer laying steps, specifically, firstly, connect one end of the L-shaped grouting pipe outlet to the elastic grouting bag, connect interface A and interface B respectively, place the elastic grouting bag into the cavity area, located on the composite isolation layer and reinforcing ribs, with the other end of the grouting outlet facing upwards and higher than the original road surface elevation.

7. The structural combination design optimization method for cement pavement repair according to claim 6, characterized in that, In the grouting layer laying step, the isolation layer of the repair area is leveled and the surface scum of the joint is cleaned. Before pouring concrete, the elastic grouting bag is pre-inflated through interface A. There are two elastic grouting interfaces A. The valve of one grouting port A is closed, and the other grouting port A is inflated to fill the cavity area. The valve of the connection port is closed. Similarly, there are connection ports B reserved at both ends of the grouting bag for connecting the mesh pipe. The grouting material is injected into the grouting bag through connection port A for filling, and the grouting material is injected into the mesh grouting pipe through connection port B and released through evenly distributed small holes.

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