A method for road repair of trenchless abandoned pipeline networks

Abstract

This invention discloses a trenchless road repair method for abandoned pipeline networks, comprising: Step 1, pipe end sealing; Step 2, pipeline cleaning; Step 3, pipe section positioning; Step 4, pile location layout and setting out; Step 5, sand-filled pile construction; Step 6, asphalt surface milling; Step 7, grouting and patching of cracks in the water-stabilized layer; Step 8, leveling layer construction; and Step 9, asphalt recycled material surface layer construction. This invention addresses abandoned pipeline networks in the roadbed by employing a trenchless method to treat pipelines that have caused road damage, and upgrades and repairs the road surface structure. This ensures the quality of the upgraded structure, maximizes the utilization of existing materials, and effectively solves problems such as uneven roadbed settlement after excavation and backfilling, large road repair workload, poor durability and integrity of the repaired structure, long construction time affecting traffic, and high costs.

Description

Technical Field

[0001] This invention relates to a road repair method, specifically a non-excavation method for repairing abandoned pipeline networks, belonging to the field of municipal engineering construction technology. Background Technology

[0002] In the past, the construction of old urban areas involved laying pipelines on roads. These pipelines were mostly plain-mouthed or shallow-mouthed socketed concrete pipes. Over time, increasingly heavy traffic led to pipeline cracking, roadbed settlement, and severe damage reflected from the road surface. Routine maintenance often involved repairing pipeline manholes and resurfacing roads with asphalt. However, this resulted in insufficient drainage capacity, poor drainage, and repetitive road repairs, which have increasingly drawn attention.

[0003] Currently, after the issue of pipeline problems gained attention, the renovation of pipelines and roads mainly involves building new pipelines and demolishing existing roads to achieve a fundamental solution. However, the excavation of abandoned pipelines leads to uneven settlement between the filling and old roadbed soil, which cannot be effectively resolved. Furthermore, since the original roads are mostly located in densely populated areas, new construction is time-consuming and costly, severely impacting people's lives, causing significant traffic congestion, and hindering economic development.

[0004] Therefore, there is an urgent need to find a way to mitigate the negative impact of pipelines on lanes, enhance the repair effect, and reduce the impact on traffic, avoid the excavation and repair of abandoned pipelines, and solve problems such as uneven settlement of the roadbed caused by backfilling, large amount of road repair work, poor durability and integrity of repair structures, and long construction time affecting traffic. Summary of the Invention

[0005] This invention addresses the shortcomings and gaps in existing technologies by providing a non-excavation method for road repair of abandoned pipelines. It avoids the need for excavation and repair of abandoned pipelines, and solves problems such as uneven settlement of the roadbed caused by backfilling, large amount of road repair work, poor durability and integrity of the repaired structure, and long construction time that affects traffic.

[0006] The present invention is implemented as follows:

[0007] A method for road repair of trenchless abandoned pipeline networks includes the following steps:

[0008] Step 1: Pipe end sealing;

[0009] Step 2: Cleaning the pipeline;

[0010] Step 3: Pipe section location detection;

[0011] Step 4: Pile location layout and setting out;

[0012] Step 5: Construction of sand-filled piles;

[0013] Step 6: Milling of the asphalt surface layer;

[0014] Step 7: Grouting and patching of cracks in the water-stabilized layer;

[0015] Step 8: Leveling layer construction;

[0016] Step 9: Construction of asphalt recycled material surface layer.

[0017] A further step is:

[0018] Step 1, pipe end sealing, specifically includes:

[0019] After the new pipeline network is connected, the manhole opening at the upstream end of the abandoned pipeline section will be sealed first. Then, after the accumulated water in the abandoned pipeline section is drained, the manhole opening at the downstream end will be sealed. After the upstream and downstream sections are sealed, the first manhole of the adjacent downstream pipeline section to be treated will be sealed with a sealing plate, and sandbags will be used for side pressure. Grouting ports will be reserved at the top of the upstream and downstream sealing sections. This small pipe section will be filled with mortar with aggregate. A grouting pipe will be installed on the top of the small pipe section. After the grouting mortar has initially set, it will be grouted to a dense state.

[0020] Step 2, pipeline cleaning, specifically includes:

[0021] The slag is dragged from upstream to downstream using slag removal equipment to the downstream manhole for cleaning. After cleaning, the remaining water in the manhole can be used to flush the pipeline under high pressure, flushing out the pipe sections and flushing them into the downstream manhole for timely cleaning and drainage.

[0022] Step 3, pipe section location detection, specifically includes:

[0023] Install the roller frame, scraper positioner, winch, etc. Then, one person manually pulls the winch slowly, senses any jamming, and reports back to the personnel inside the well; another person enters the bottom of the upstream well chamber and uses an infrared laser pointer to assist in observing the scraper positioner, and uses a walkie-talkie to transmit the adjustment of the pulling speed and confirm whether it is a pipe section; another person on the road uses a locator to track the scraper positioner signal along the pipeline direction, and lays out the pipeline direction and the location of underground pipe sections.

[0024] Step 4, pile location layout and setting out, specifically includes:

[0025] Based on the pipeline and pipe sections laid out through the pipe section exploration, the actual situation is fed back to the drawings. According to the actual pipeline deviation and the location of the pipe sections, the pile positions are arranged according to the design requirements. For areas with severe breakage and settlement, the treatment range is marked according to the design requirements, and the pile positions are arranged from the center outwards according to the spacing requirements. Based on the layout measurement and layout, the pile positions are marked on the road surface using spray paint.

[0026] Step 5, Sand-filling pile construction, specifically includes:

[0027] Filter plates are installed near the upstream pipe opening of each well chamber. Using drilling equipment such as impact drills and auger drills, and based on the marked pile positions, adjacent well chamber sections are used as units. First, sand-filled piles are constructed along the centerline of the pipeline network. The downstream well cover is removed, and the installed dewatering filter pipes are drained. Holes are drilled sequentially from downstream to upstream, and sand-filled guide buckets are installed. Sand is poured while water is injected and the piles are compacted with a hammer. Then, for the pipeline side piles and areas with severe roadbed settlement, holes are drilled sequentially from the center outwards, sand-filled guide buckets are installed, and sand is poured while compacting with a hammer. After pile construction, once there is no large amount of standing water drained from the dewatering filter pipes, the well chambers are filled with sand and compacted, and the dewatering filter pipes are removed for recycling. The upper layer of water-stabilized soil on the sand-filled piles is manually cleaned, the rough edges of the ducts are manually cleaned, and the pile tops are compacted. Micro-expansion C15 concrete is used for capping.

[0028] Step 6, asphalt surface milling, specifically includes:

[0029] The portion above the water-stabilized layer in the well chamber is cleaned. A material similar in composition to the original water-stabilized layer is then used to fill and compact the compacted well chamber, creating a roughened surface. After 7 days of curing, an asphalt surface layer is milled using an asphalt milling machine. The asphalt milled in layers is transported to the mixing plant and stored separately.

[0030] Step 7, grouting and patching of cracks in the water-stabilized layer, specifically includes:

[0031] After milling the asphalt surface, the surface of the water-stabilized layer is cleaned of floating slag, and then the cracks and fissures on the relatively intact surface are cleaned and grouting or injection is performed; the broken and severely settled surfaces are removed, the bottom sand cushion layer is filled and compacted, the water-stabilized layer is broken in place to form loose granules, a small amount of water is poured to wet it without standing water, cement is added and mixed, and then the removed parts are filled and compacted, and the surface is roughened.

[0032] Step 8, leveling layer construction, specifically includes:

[0033] After the crack grouting and water-stabilized base construction has been completed for ≥48 hours and the strength has reached 25%, wash away the laitance and soil formed on the surface due to grouting and other construction work, sweep away any obvious water accumulation in low-lying areas, and apply a thin layer of cement. Then, use a bamboo broom to sweep the cement evenly, ensuring there are no clumps or silt, lay a layer of geonet, spread a layer of fine stone water-stabilized material, and use a roller of no more than 12t to statically compact it 3-4 times. Level and repair the milled rough water-stabilized base surface, and water-cur it for ≥14 days.

[0034] Step 9, construction of the recycled asphalt surface layer, specifically includes:

[0035] After the curb stones and other ancillary facilities are repaired, oil is spread on the leveling surface, and the original milled asphalt material is mixed in a centralized plant to form recycled material for paving, compaction and other construction work on the original road surface.

[0036] The technical solution of the present invention has the following technical effects:

[0037] (1) By adopting the non-excavation disposal method to reconstruct the pipeline network and repair the road, the underground pipeline network is reasonably abandoned and the road is quickly repaired, avoiding the risk of uneven settlement of the old roadbed due to excavation and backfilling, reducing the impact of large-scale excavation on traffic and the safety risks of foundation pit excavation.

[0038] (2) This repair method maximizes the use of the original road materials and preserves the road structure layer to the maximum extent, which meets the requirements of economy, greenness and environmental protection, and effectively controls the cost of such projects using the EPC model.

[0039] (3) The treatment of abandoned pipelines only requires simple traffic guidance, which does not affect normal construction and traffic. The road surface repair time after the abandoned pipelines are disposed of is short and less affected by the weather.

[0040] (4) The use of scraper probes, positioners, roller frames, winches and other systems to explore the condition of abandoned pipelines can be done manually and conveniently. The condition of the pipe sections can be determined quickly, and the on-site pile positions can be arranged quickly.

[0041] (5) Sand-filled piles can fill the pipeline with sand, which effectively treats the weak roadbed caused by the pipeline, effectively preserves the original roadbed structure layer, and realizes the squeezing, solidification and compaction of the pipeline roadbed.

[0042] (6) Grouting and cutting and patching the cracks in the water-stabilized layer to repair the water-stabilized layer and enhance the integrity and bearing capacity of the water-stabilized structural layer.

[0043] (7) After the asphalt layer is milled, the surface of the water-stabilized layer is loose. Cement slurry is sprayed to solidify it, and geonet is used to reinforce it. After the cement slurry has no water, a thin layer of fine stone water-stabilized layer is laid to level the base surface, which not only repairs and levels the base surface, but also ensures the integrity of the base surface.

[0044] Overall, this invention addresses abandoned pipelines embedded in roadbeds using a trenchless method to repair pipelines damaged by roadworks, and upgrades and repairs the road surface structure. This ensures the quality of the upgraded structure, maximizes the utilization of existing materials, and effectively solves problems such as uneven roadbed settlement after excavation and backfilling, large road repair workload, poor durability and integrity of the repaired structure, long traffic disruptions, and high costs. Specifically designed for the repair of roads rebuilt from pipelines, it fills the gap in environmentally friendly repair technology for roads damaged by pipeline issues, providing an economical, stable, green, environmentally friendly, safe, and reliable method for EPC projects. Attached Figure Description

[0045] Figure 1 A schematic diagram showing the layout of the repair pile locations;

[0046] Figure 2 This is a schematic diagram of the construction process before repair;

[0047] Figure 3 This is a schematic diagram of the sand-filled pile construction stages;

[0048] Figure 4 This is a schematic diagram of the water-stabilized layer repair stage;

[0049] Figure 5 This is a schematic diagram of the completed repair work.

[0050] Among them, 1-concrete pipe, 2-well chamber, 3-sand pile, 4-mortar, 5-water-stabilized layer, 6-crack, 7-sealing plate, 8-sandbag, 9-scraper probe, 10-winch, 11-positioner, 12-roller frame, 13-crack grouting, 14-sand guide bucket, 15-hammer, 16-dewatering filter pipe, 17-filter plate, 18-repair water-stabilized layer, 19-C15 concrete, 20-leveling layer, 21-recycled asphalt surface layer, 22-small pipe section. Detailed Implementation

[0051] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0052] As attached Figure 1 To be continued Figure 5 As shown in the figure, this embodiment provides a road repair method for trenchless abandoned pipeline networks, including the following steps:

[0053] Step 1, Pipe end sealing:

[0054] Abandoned pipeline sections generally consist of upstream and downstream manholes 2 and a concrete pipe 1 connecting the upstream and downstream manholes. After the new pipeline network is connected, the manhole opening at the upstream end of the abandoned pipeline section is first sealed; then, after the accumulated water in the abandoned pipeline section is drained, the manhole opening at the downstream end is sealed. After the upstream and downstream sections are sealed, the first manhole of the adjacent downstream pipeline section to be treated is sealed with a sealing plate 7, and the bottom is pressed with sandbags 8. Grouting ports are reserved at the top of the upstream and downstream sealing sections, and this small pipe section 22 is filled with mortar 4 with aggregate; a grouting pipe is installed on the top of the small pipe section 22, and the grouting is compacted after the grouting mortar has initially set.

[0055] The upstream and downstream are determined according to the flow direction of the water in the pipeline network. In this embodiment, the upstream and downstream positions are shown in the attached figure. The small pipe segment 22 is the pipe segment connecting the upstream and downstream end chambers of the repair and sealing section (such as the connecting branch pipe segment entering the main road network).

[0056] Step 2, Pipeline cleaning: Use slag removal equipment to drag the deposited residue from upstream to downstream to the manhole at the downstream end for cleaning. After cleaning, the water remaining in the manhole can be used to flush the pipeline under high pressure to flush out the pipe sections and flush them into the downstream manhole for timely cleaning and drainage.

[0057] Step 3, Pipe section location: as shown in the attached document. Figure 2As shown, first install the roller frame 12, scraper probe 9, winch 10, etc. Then, one person manually operates the winch to slowly pull back and forth, sensing any jamming and reporting back to the personnel inside the well; another person enters the bottom of the upstream well chamber through the upper and lower pipe openings, using an infrared laser pointer to assist in observing the scraper probe, and using a walkie-talkie to transmit the adjustment of the pulling speed and confirm whether it is a pipe section; another person on the road uses a handheld locator 11 to track the scraper probe signal along the pipeline direction, laying out the pipeline route and the location of underground pipe sections.

[0058] Step 4, Pile location layout and setting out: as shown in the attached document. Figure 1 As shown, based on the pipeline and pipe sections laid out by the pipe section exploration, the actual situation is fed back to the drawings. Based on the actual pipeline deviation and the location of the pipe sections, the pile positions are arranged according to the design requirements. For areas with severe breakage and settlement, the treatment range is marked according to the design requirements, and the pile positions are laid out from the center outwards according to the spacing requirements. Based on the layout measurement and layout, the pile positions are marked on the road surface using spray paint.

[0059] Step 5, Sand-filled pile 3 construction: as attached Figure 3 As shown, filter plates 17 are installed near the upstream pipe opening of each well chamber. Using drilling equipment such as impact drills and auger drills, and based on the layout of the pile positions, adjacent well chamber sections are used as units. First, sand-filled piles are constructed along the centerline of the pipeline network. The downstream well cover is removed, and the installed dewatering filter pipe 16 is used to pump out water. Holes are drilled sequentially from downstream to upstream, and sand-filled guide buckets 14 are installed. Sand is poured while water is injected, and the piles are tamped with a hammer 15. Then, for the pipeline side piles and areas with severe roadbed settlement, holes are drilled sequentially from the center outwards, sand-filled guide buckets are installed, and sand is poured while the piles are tamped with a hammer. After the pile construction is completed and there is no large amount of standing water being pumped out of the dewatering filter pipe, the well chamber is filled with sand and compacted, and the dewatering filter pipe is removed for recycling. The upper layer of water-stabilized bottom of the sand-filled piles is manually cleaned, the rough edges of the ducts are manually cleaned, and the pile top is tamped. Micro-expansion C15 concrete 19 is used to seal the top.

[0060] Step 6, Asphalt surface milling: as shown in the attached document. Figure 4 As shown, the portion of the water-stabilized layer above 5 in the well chamber is cleaned. A material similar in composition to the original water-stabilized layer is then used to fill and compact the compacted well chamber, creating a roughened surface. After 7 days of curing, an asphalt surface layer is milled using an asphalt milling machine. The asphalt milled in layers is transported to the mixing plant and stored separately.

[0061] Step 7, Grouting and patching of crack 6 in the water-stabilized layer: as attached Figure 4 As shown, after milling the asphalt surface, the surface of the water-stabilized layer is cleaned of floating slag, and then the cracks and fissures on the relatively intact surface are cleaned and grouting or injection is performed; the broken and severely settled surfaces are cut off, the bottom sand cushion layer is filled and compacted, the water-stabilized layer is broken on the spot to form loose granular material, a small amount of water is poured to wet it without standing water, cement is added and mixed, and then the cut-off parts are filled and compacted, and the surface is roughened to form a repaired water-stabilized layer 18.

[0062] Step 8, Leveling layer 20 construction: as attached Figure 5 As shown, after the crack grouting and water-stabilized base construction have been carried out for ≥48 hours and the strength reaches 25%, the surface laitance and soil formed by grouting and other construction are washed away, and some obviously accumulated water in low-lying areas is swept away. A thin layer of cement is then sprayed. Then, a bamboo broom is used to sweep the sprayed cement evenly, without any clumps or silt. A layer of geonet is laid, followed by a layer of fine stone water-stabilized material. A road roller with a capacity not exceeding 12t is used for static compaction 3-4 times to compact the surface. The rough water-stabilized base surface is then leveled and repaired, and water is sprayed for curing for ≥14 days.

[0063] Generally, the strength of cracks after grouting should reach 75% of the required strength. However, since the strength of cracks rises quickly and is high after grouting, a surface repair is also required. This is a thin-layer patch, and the cracks under the repaired water-stabilized layer need to be compacted under static pressure to remove any voids. Therefore, after the strength reaches 25%, rolling and leveling can be carried out.

[0064] Step 9, Construction of the recycled asphalt surface layer: as shown in the attached document. Figure 5 As shown, after the repair of the curb stones and other ancillary facilities, oil is spread on the leveling surface, and the original milled asphalt material is mixed into recycled material at the centralized plant to pave and compact the original road surface layer, forming a recycled asphalt surface layer 21.

[0065] The main technical features and requirements for each step are as follows:

[0066] (1) The pipe section is sealed. The sealing should be done upstream first and then downstream. A small amount of micro-expansion agent should be added to the aggregate mortar for grouting the small pipe section. Grouting pipes should be installed on the top of the small pipe section to fill the small pipe section with a sealed chamber.

[0067] (2) The pipeline cleaning mentioned above should be carried out in units of two adjacent manholes, proceeding sequentially from upstream to downstream, and should not be carried out in reverse. Before the slag is removed from the manhole, the air quality inside the manhole should be monitored, and ventilation facilities may be added if necessary.

[0068] (3) For the pipe section probing, the personnel holding the winch should be responsible, have a good feel for the winch, and be able to control the speed of the winch. All three should hold walkie-talkies on the same channel to facilitate communication and control accuracy.

[0069] (4) The pile locations and layout should be as follows: the pile diameter should be 100mm to 350mm; piles should be placed on both sides of the pipe section, but not on the center line of the pipe section; the center line and the piles on both sides should be staggered in a quincunx pattern; the net distance between piles perpendicular to the pipe should be 200mm to 600mm; and the net distance between each row of piles along the pipe should not exceed 1500mm. For severely broken or settled surfaces, excavation is required. The excavation shape should be rectangular or square, and other shapes, such as circles, are not allowed. Rectangular or square shapes should not be oblique to the road direction; the net distance between adjacent piles should be 500mm to 800mm and arranged in a quincunx pattern.

[0070] (5) The sand-filling pile construction shall be carried out sequentially from downstream to upstream, with each adjacent well chamber as a unit. The material selected shall be well-graded river sand aggregate with a mud content of <5%. Aggregates with particle sizes <0.3mm and >26.5mm shall be screened out. Sharp-edged sand aggregates are not recommended to facilitate pipe filling and water vibration for silt removal. The depth of the pile holes along the pipeline centerline shall be ≥300mm from the bottom of the pipe, and, depending on the soil quality obtained during drilling, the depth shall penetrate a wet soft soil layer of ≥200mm. For pile positions on fractured or severely settled surfaces and on both sides of the pipeline, the depth shall penetrate a wet soft soil layer of ≥300mm, depending on the soil quality obtained during drilling. The net distance between the drilling equipment and the sand-filling related equipment shall be >5000mm. For the sand-filling guide bucket, the outer diameter of the guide tube should be 5mm-10mm smaller than the borehole diameter. The insertion depth should be such that the bottom of the bucket is suspended at a height ≤200mm before sand filling. Each subsequent pull should not exceed the top surface of the sand-filled pile. After compaction, the pull-out amount should be 120mm-350mm to ensure pile quality. Specifically, for sand-filled piles along the pipeline centerline, the process of "water injection, slow lifting, and multiple hammerings" should be maintained. Water injection should be carried out after compaction at the bottom of the pipe to ensure the sand fills the pipeline and is compacted. The outer diameter of the hammer should be 10mm-20mm smaller than the outer diameter of the sand-filling guide bucket. The hammer drop height and the number of hammerings in each section after filling need to be determined after test piles.

[0071] (6) For the asphalt surface milling, the well chamber should be sealed before milling. Milling should be done in layers. After milling, the aggregate should be sorted and stacked to facilitate recycling. Local low-lying areas should be manually excavated.

[0072] (7) For the grouting and patching of cracks in the water-stabilized layer, if there is a sand cushion layer under the original ground water-stabilized layer, the grouting pipe can be extended to the bottom surface of the water-stabilized layer; otherwise, it should be extended to 1 / 3 of the thickness of the water-stabilized layer from the bottom. For wider cracks with intact surrounding water-stabilized layers, grouting and smoothing can be done directly. For patching, if double-layer water-stabilized layer treatment is involved, a stagger of not less than 200mm should be set between the two layers to ensure interlocking between the two layers. The aggregate should be crushed on-site to form loose particles of water-stabilized material, and the original water-stabilized cement mix ratio should be added for mixing, spreading, and compaction. After compaction, the surface should be roughened.

[0073] (8) For the construction of the leveling layer, the thin layer of cement should be 42.5 silicate cement, the geonet should be made of nylon, fine wire type, and dense mesh with a diameter of ≥28mm, and the fine stone water-stabilized material should be laid and compacted to a thickness of ≥5cm (the thinnest part should be ≥2cm).

[0074] (9) The asphalt recycled surface layer shall have at least 30% of well-graded aggregates added to the recycled material, and the strength of each particle size in the aggregate shall be at least one grade higher than that of the original aggregate.

[0075] Although the present invention has been described herein with reference to illustrative embodiments, the above embodiments are merely preferred embodiments of the present invention, and the implementation of the present invention is not limited to the above embodiments. It should be understood that those skilled in the art can devise many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A method for road repair of trenchless abandoned pipeline networks, characterized in that... Includes the following steps: Step 1, Pipe End Sealing; specifically includes: after the new pipeline is connected, first seal the manhole opening of the upstream end of the abandoned pipeline section; then, after the accumulated water in the abandoned pipeline section is drained, seal the manhole opening of the downstream end; after the upstream and downstream are sealed, the bottom of the first well of the adjacent downstream pipeline section to be treated is sealed with a sealing plate, and sandbags are used for side pressure. Grouting ports are reserved at the top of the upstream and downstream sealing, and this small pipe section is filled with aggregate mortar; a grouting pipe is installed on the top of the small pipe section, and the grouting is compacted after the grouting mortar has initially set; Step 2, Pipeline cleaning; specifically includes: using slag removal equipment to drag the deposited residue from upstream to downstream to the manhole at the downstream end for cleaning, and then using the water remaining in the manhole to perform high-pressure flushing of the pipeline to flush out the pipe sections, which are then promptly cleaned and drained from the downstream manhole. Step 3, pipe section location; specifically includes: Install the roller frame, scraper probe, and winch; then, one person manually pulls the winch slowly, sensing for any jamming and reporting back to the personnel inside the well; another person enters the bottom of the upstream well chamber and uses an infrared laser pointer to assist in observing the scraper probe, and uses a walkie-talkie to transmit the adjustment of the pulling speed and confirm whether it is a pipe section; another person on the road uses a locator to track the scraper probe signal along the pipeline direction, and lays out the pipeline direction and the location of the underground pipe section. Step 4, pile location layout and setting out; specifically including: Based on the pipeline and pipe sections laid out by the pipe section exploration, the actual situation is fed back to the drawings. Based on the actual pipeline deviation and the location of the pipe sections, the pile positions are laid out according to the design requirements. For broken or severely settled surfaces, the treatment range is marked according to the design requirements, and the pile positions are laid out from the center outward according to the spacing requirements. Based on the layout measurement and layout, the pile positions are marked on the road surface using spray paint. Step 5: Sand-filled pile construction; specifically including: Filter plates are installed at the upstream pipe opening of each well chamber. Using drilling equipment, the construction of sand-filled piles is carried out first on the pipeline centerline, based on the layout pile positions and the adjacent two well chambers as units. The downstream well chamber cover is pried off and a dewatering filter pipe is installed to pump out water. Holes are drilled sequentially from downstream to upstream, and sand-filled guide buckets are installed. Water is injected and the piles are compacted with a chisel while sand is being poured in. Then, holes are drilled sequentially from the center outwards for the pipeline side piles and the severely settled parts of the roadbed. Sand-filled guide buckets are installed and the piles are compacted with a chisel while sand is being poured in. After the pile construction is completed, the well chambers are filled with sand and the dewatering filter pipes are pulled out for recycling. The water-stabilized bottom of the sand-filled piles is manually cleaned, the rough edges of the holes are manually cleaned, and the pile tops are compacted. Micro-expansion C15 concrete is used to seal the top. Step 6: Milling of the asphalt surface layer; specifically including: Clean the part above the water-stabilized layer of the well chamber, fill and compact the well chamber with a material similar to the original water-stabilized layer mix, and roughen the surface. After 7 days of curing, use an asphalt milling machine to mill the asphalt surface layer. The asphalt milled in layers is transported to the mixing plant and stored separately. Step 7: Grouting and patching of cracks in the water-stabilized layer; specifically including: After milling the asphalt surface, the surface of the water-stabilized layer is cleaned of floating slag, and then the relatively intact surface is cleaned. Cracks and fissures are grouted or injected. The broken or severely settled surfaces are removed, the bottom sand cushion layer is filled and compacted, the water-stabilized layer is broken in place to form loose granules, a small amount of water is poured to wet it without standing water, cement is added and mixed, and then the removed parts are filled and compacted, and the surface is roughened. Step 8: Leveling layer construction; specifically includes: After the crack grouting and water-stabilized base construction has been carried out for ≥48 hours and the strength has reached 25%, the surface laitance and soil formed by the grouting construction are washed away, and some obvious water accumulation in low-lying areas is swept away. A thin layer of cement is then spread. Then, a bamboo broom is used to sweep the spread cement evenly and remove any clumps. A layer of geonet is laid, and a layer of fine stone water-stabilized material is spread. A road roller with a capacity of no more than 12t is used to statically compact the material 3 to 4 times. The surface is then leveled and repaired, and the rough water-stabilized base surface is water-cured for ≥14 days. Step 9: Construction of the recycled asphalt surface layer, specifically including: After the curb stones are repaired, oil is spread on the leveling surface, and the original milled asphalt material is mixed in a centralized plant to form recycled material for paving and compaction of the original road surface.

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