Quick repair construction method for collapse of municipal drainage pipeline in quicksand geology

Abstract

The invention discloses a quick repair construction method for collapse of municipal drainage pipelines in quicksand geology, which can quickly finish pipeline repair work without earth excavation under the quicksand geology condition, ensure the travel safety of vehicles and pedestrians and reduce the influence on the surrounding environment, and conforms to the current concept of green construction.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline repair, and in particular relates to a construction method for quickly repairing a collapsed municipal drainage pipeline in quicksand geology. Background Art

[0002] Large-diameter urban drainage pipes, due to their large diameter, are often installed on municipal roads. Their primary function is to collect stormwater and sewage from major urban drainage areas, playing a crucial role in urban development. After long periods of operation, buried urban drainage pipes inevitably develop defects, such as disconnection, deformation, leakage, rupture, and subsidence. Large-diameter pipes (over 1000mm) are particularly susceptible to subsidence, particularly in areas of quicksand. Subsidence can range from a few square meters to hundreds of square meters. In minor cases, this can cause road subsidence, impacting vehicle and pedestrian safety; in severe cases, it can compromise the safety of nearby underground structures and pipelines. Currently, the most commonly used repair methods include in-situ reconstruction, trenchless repair, and relocation. Trenchless repair offers a smaller footprint and faster repair times, but cannot repair large-diameter pipes and is expensive. Relocation repair takes a long time and affects a wider area. In-situ reconstruction offers the advantages of both methods, but is limited by the quicksand geology, lacking support points for excavating and supporting the pipes, making it impossible to use excavators for buried pipe repair. Summary of the Invention

[0003] To solve the above problems, the present invention discloses a construction method for rapid repair of municipal drainage pipeline collapse in quicksand geology. It is optimized on the basis of in-situ reconstruction, so that the pipeline can be quickly repaired under quicksand geological conditions, reducing the risk of earth collapse, thereby ensuring the travel safety of vehicles and pedestrians.

[0004] To achieve the above object, the technical solution of the present invention is as follows: The quick repair construction method for the collapse of municipal drainage pipelines in quicksand geology includes the following steps: (1) Construction preparation and installation of drainage pipes; (2) Install a vertical drainage pump in the well and connect it to the drainage pipe; (3) Soil reinforcement; (4) Construction of pipe jacking working well using reverse method; (5) Rock pipe jacking machine pipe jacking construction.

[0005] Furthermore, the construction preparation described in step (1) includes on-site inspection, formulating repair methods, determining the construction sequence, preparing materials and tools, installing drainage pipes, and coordinating power supply, transportation, and garbage disposal.

[0006] Furthermore, in step (2), an inverted drain pipe is installed next to the collapsed pipe. The details of dismantling the collapsed pipe are as follows: Dig up the collapsed soil and bury an inverted drainpipe beside the collapsed pipeline. The two ends of this pipe are connected to the upstream well and downstream well water pumps. This pipe is parallel to the direction of the collapsed pipeline and is in parallel with the collapsed pipeline. It is used as a drainage pipe for drainage operations when the pipeline is repaired. After the repair is completed, it will not be removed and will be retained as a spare pipe. If there is a pipeline problem later, it can be used as a temporary inverted drainpipe to convert the temporary drainage facility into a permanent drainage facility, which is convenient for subsequent pipeline inspection and maintenance. After the inverted drainpipe is installed, the collapsed pipeline will be removed.

[0007] Furthermore, the soil reinforcement using high-pressure jet grouting piles in step (3) is achieved by injecting cement slurry into the soil layer within 2 m of the collapsed pipe using high-pressure jet grouting piles, and the strength of the reinforced soil can reach 1.5 MPa.

[0008] Furthermore, the cement slurry uses 42.5 grade ordinary Portland cement. When mixing the mortar, add water first and then add cement. The mixing time is ≥30s when using a high-speed mixer and ≥90s when using an ordinary mixer. The cement slurry is used as soon as it is prepared.

[0009] Furthermore, the pipe jacking working well described in step (4) adopts a reverse construction process, and is constructed layer by layer from top to bottom, with each layer being 1-1.5m, and is excavated and constructed layer by layer until the bottom is reached.

[0010] Furthermore, the pipe jacking process in step (5) is: Install a guide rail at the bottom of the working well, fix a hydraulic cylinder at the rear end, place the first section of the pipeline on the guide rail, start the hydraulic cylinder to push it into the soil layer, use a tunnel boring machine to excavate and discharge the soil until the front end of the pipeline enters the receiving well, and continue grouting during the jacking process to fill the gap between the pipe wall and the soil to prevent ground subsidence.

[0011] Furthermore, relay rooms are installed in sections in long-distance jacking pipes.

[0012] The beneficial effects of the present invention are: The method for quickly repairing a collapsed municipal drainage pipeline in a quicksand geological environment described in the present invention achieves the purpose of safely and quickly repairing the pipeline under quicksand geological conditions by combining soil reinforcement technology, shallow buried pipeline drainage technology, and rapid pipe jacking technology.

[0013] (1) High bearing capacity: High-pressure jet grouting piles are used to reinforce the surrounding soil to form a cement soil foundation. At the same time, the groundwater and soil are solidified, and the bearing capacity of the foundation is improved, which has a wide range of applicability.

[0014] (2) Lower cost: No excavation support is required, which saves a lot of support costs. It is not only simple to construct, but also much more economical than traditional excavation construction.

[0015] (3) Fast construction speed: Since there is no need to excavate trenches or provide support, the original pipeline is simply replaced by jacking, which is very fast.

[0016] (4) Energy saving and environmental protection: Since no excavation is required, municipal roads and green areas will not be damaged. It is environmentally friendly and meets the requirements of green construction. It is not affected by seasons and can be constructed all year round. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a construction process flow chart of the present invention.

[0018] Figure 2 This is the reverse construction flow chart of the working well.

[0019] Figure 3 This is a schematic diagram of the installation of the inverted discharge pipe described in the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0021] The invention discloses a method for rapidly repairing a collapsed municipal drainage pipeline in quicksand geology. The method is based on the principle of shallowly burying a temporary drainage pipeline next to the collapsed pipeline, then reinforcing the foundation of the collapsed area with high-pressure jet grouting piles, and constructing a new caisson to implement rock jacking to complete pipeline replacement.

[0022] Specifically, a shallowly buried pipe is buried alongside the collapsed pipe to serve as a drainage pipe during pipe repair. After the repair is complete, the pipe is retained as a backup pipe, serving as a temporary drainpipe should any problems arise, transforming the temporary drainage facility into a permanent one. High-pressure jet grouting piles are then used to reinforce the soil within 2 meters of the collapsed pipe, increasing the bearing capacity of the foundation, ensuring the safety of subsequent pipe jacking construction, and speeding up the jacking process. Finally, a new caisson is constructed and a rock jacking pipe is erected to replace the pipe.

[0023] Innovations of the present invention: 1. Dynamic grouting reinforcement technology for quicksand layers: By dynamically controlling grouting parameters, rapid-setting reinforcement materials are pneumatically injected into the quicksand geology, so that the quicksand geological soil is solidified, thereby increasing the soil's bearing capacity and improving the strength and stability of the quicksand layer.

[0024] 2. Composite drainage system technology: During the repair of collapsed pipelines, shallow buried drainage pipes are combined with drainage wells to form an efficient vertical and horizontal drainage network, achieving precise diversion and dynamic drainage. After the repair is completed, the drainage system will not be dismantled, making it convenient for subsequent units to carry out pipeline operation and maintenance work.

[0025] 3. In-situ pipe replacement composite pipe jacking technology: Combine the pipe cracking device with the pipe jacking machine, use the jacking pipe to drive the pipe cracking device, and achieve the replacement of pipes in the original position, with the same diameter and material without affecting the surrounding environment.

[0026] Quick repair construction method for municipal drainage pipeline collapse in quicksand geology, such as Figure 1 As shown, the following steps are included: 1. Construction Preparation 1. Safety technology briefing Before construction, the work team will be organized to conduct on-site surveys and inspections, formulate repair methods, and conduct safety technical briefings. The briefings mainly include: 1) Construction sequence and construction methods; 2) Construction precautions, 3) Safety precautions; 4) Temporary power safety operation content and traffic organization operation content; 2. Preparation of materials and equipment Contact the commercial concrete mixing station before construction to ensure the continuity of concrete pouring; the formwork must be guaranteed not to explode during construction.

[0027] 3. Temporary facilities 1) Power supply: Diesel generators are used on site as the power source for the construction site; 2) Sewage and garbage disposal: Temporary filtration pools will be set up at the construction site to centrally treat sewage generated during construction, and domestic and industrial garbage will be centrally stored and transported away for disposal, to ensure that the natural environment of the construction area is not damaged to the greatest extent possible; 3) Temporary land use: The construction area is enclosed by fencing.

[0028] 2. Install the inverted pipe Based on the location of the pipeline to be repaired, bricks or air bags were used to temporarily seal the two well chambers upstream and downstream of the pipeline. Once the sealing was completed, drainage equipment (350QH40-45, submersible mixed flow pump) was installed and drainage pipe (450mm diameter PE pipe) was laid.

[0029] Dig up the collapsed soil and bury the drainage pipe beside the collapsed pipeline. The two ends of this pipe are connected to the upstream well and the downstream well water pump. Figure 3 As shown, this pipe is parallel to the direction of the collapsed pipe and is in parallel with the collapsed pipe. It is used as a drainage pipe for drainage operations when the pipeline is repaired. It is not removed after the repair is completed, and the pipe is retained as a spare pipe. If there is a pipeline problem later, it can be used as a temporary backflow pipe to convert the temporary drainage facility into a permanent drainage facility. After the backflow pipe is installed, the collapsed pipe is removed.

[0030] 3. High-pressure jet grouting piles to reinforce soil 1. Level the site First, the site is leveled, and obstacles above and below the ground at the pile locations are cleared, and then the site is leveled and compacted; at the same time, the locations of construction machinery, transportation pipelines, and power lines are reasonably arranged to ensure the "three connections and one leveling" of the construction site.

[0031] 2. Earth excavation After site leveling for high-pressure jet grouting piles, a drainage ditch 1.0m deep and equal to the width of the high-pressure jet grouting piles will be excavated from the original ground, based on the center of the piles. For high-pressure jet grouting piles located on roads, the road surface must be cut, broken, and restored before construction. The drainage ditch will be equal to the width of the high-pressure jet grouting piles and 1.0m deep.

[0032] 3. Measurement and positioning Before construction, a total station is used to determine the control points for the jet grouting pile construction. After passing the retest and acceptance, a steel ruler and a survey line are used to lay out the pile positions on site, and they are nailed down with bamboo sticks, one stick at a time, to ensure that the displacement deviation of the pile hole center is less than 50mm.

[0033] 4. Put the machine in place After the drilling rig is in place, a dedicated person will direct the pile driver to be leveled using a spirit level and a positioning hammer. The guide frame and drill rod should be perpendicular to the ground with an inclination of less than 1.5%. Any drill rod that does not meet the required verticality should be adjusted until it reaches the required verticality. To ensure accurate pile placement, a positioning card must be used, and the pile centering error should not exceed 5 cm.

[0034] 5. Drilling Single-tube construction method: Single-tube high-pressure rotary jet piles are subjected to high-pressure grouting during the drilling process. If underground cavities are encountered, the sand filling method is used first to treat them.

[0035] 6. Slurry preparation The rotary jet slurry uses 42.5-grade ordinary Portland cement. When mixing the slurry, add water first, then cement. The mixing time should be at least 30 seconds with a high-speed mixer and at least 90 seconds with a standard mixer. The cement slurry should be prepared one hour before use and used within four hours. The slurry should be continuously stirred in the mortar mixer until just before spraying. During spraying, the slurry is filtered through a screen as it is poured from the mortar mixer into the aggregate hopper to remove any hardened cement lumps. The slurry is then delivered via a hose to the nozzle of the rotary vibrating drill for final ejection.

[0036] 7. Jet grouting 1) Before inserting the jet nozzle, check the high-pressure equipment and piping system. The pressure and displacement of the equipment must meet the design requirements. The sealing rings of each part must be in good condition, and there must be no debris in the channels and nozzles. Perform a high-pressure water jet test. Only after passing the test can the slurry be sprayed.

[0037] 2) All process parameters of the rotary grouting system must be controlled in accordance with pre-set requirements, and records of rotary grouting time, slurry volume, slurry bubbling, pressure changes, etc. must be kept at all times.

[0038] 3) When spraying, the predetermined spraying pressure (the predetermined spraying pressure is 20-25MPa) should be reached first, and the spraying should be rotated for 30 seconds. After the cement slurry and the pile end soil are fully mixed, the grouting pipe should be raised by rotating in the reverse direction at a uniform speed while spraying. The lifting speed should be 10-20cm / min. When it is 1m away from the pile top, the mixing speed and lifting speed should be slowed down to ensure that the pile top is dense and uniform. The slurry stopping surface should be 50cm higher than the pile top elevation.

[0039] 4) When a fault occurs in the middle, the lifting and rotary grouting should be stopped to prevent the pile from being interrupted. At the same time, the fault should be checked and eliminated immediately. The hole section where the grouting is restarted should overlap with the previous section by no less than 0.1m to prevent the consolidated body from being disconnected.

[0040] 8. Rinse After the spraying construction is completed, the grouting pipe and other equipment should be rinsed with clean water to prevent solidification and blockage. No cement slurry should remain in the pipe or machine. Usually, the slurry is replaced with clean water and sprayed on the ground to completely drain the slurry from the slurry pump, grouting pipe and hose.

[0041] 9. Drilling rig relocation When the jet grouting is raised to 50cm above the designed pile top elevation, stop the jet grouting, lift the drill bit out of the hole, clean the grouting pump and delivery pipeline, then move the drilling rig, repeat the above operations, and proceed to the construction of the next pile.

[0042] 4. Reverse working well construction The specification of the reverse well of the present invention is φ2.5 reverse well, with a wall thickness of 500mm, a main concrete strength of C30, and an anti-seepage grade of P6. Figure 2 As shown: After the construction of the jet grouting water-stop curtain is completed, the first layer of earthwork excavation is carried out. During the excavation process, the water is pumped out from the well. At the same time, the foundation pit and the surrounding environment are monitored. Parts that cannot be directly excavated by machinery are excavated manually, cleaned, piled up, and loaded for transportation. The excavation of the foundation pit is carried out in layers using a long-arm excavator and manual labor. The excavation depth of each layer is 1-1.5m. According to the requirements of the design drawings, a soil pit about the height of a retaining wall section is dug at the positioned well. Then, according to the design requirements, the steel bars are tied and the formwork of the first section is set up. Then, concrete is poured and maintained. Then, the excavation is continued to carry out the construction of the second retaining wall. The above steps are followed until the designed well bottom. The first section of the well guard wall is dug to a depth of 1-1.5m. The guard arm is wall-mounted, 500mm beyond the outer wall of the well and 350mm thick. The guard wall template is installed, and the concrete guard wall and wellhead ring beam are poured. One section every two days is considered a construction cycle. To ensure the verticality of the well, the well center position and verticality are checked once after pouring three sections of the guard wall. The verticality correction method is to draw a cross intersection diagonally from the top of the well body as the well center, then use a plumb line to lead into the well as a well center, and use this plumb line to measure the verticality. After the upper concrete is poured and the strength reaches 80% of the design strength, the lower soil is excavated. During the reverse excavation process, if groundwater leakage is found, the following method is used to deal with it: insert a drainage pipe at the defect, then use high-strength cement mortar to seal the defect, and then close the diversion pipe after the sealing cement forms a certain strength. If the leakage is more serious, the pit should be backfilled with soil to block the water flow first, and then drill holes outside the pit to inject polyurethane to seal the leakage. After sealing, continue excavating downwards.

[0043] 5. Pipe jacking construction 1. Construction Preparation 1) Equipment installation and debugging Guide rail installation: Install the guide rail at the bottom of the working pit to ensure the accurate direction of the pipeline jacking.

[0044] Fixed hydraulic cylinder provides jacking power.

[0045] The tunnel boring machine is in place: the cutter head, soil bin and other tunnel boring equipment are installed and debugged.

[0046] 2) Geological survey: clarify the properties of soil layers, groundwater levels, and the distribution of obstacles.

[0047] 3) Design and planning: determine the pipe jacking route, working well and receiving well locations, and pipeline materials.

[0048] 2. Initial jacking 1) Pushing the first section of pipe into the soil: Place the first section of pipe on the guide rail and start the hydraulic cylinder to push it into the soil.

[0049] 2) Excavation and soil discharge: Excavation and soil discharge are carried out mechanically to keep the excavation surface stable.

[0050] 3) Measurement and correction: Monitor the pipeline axis position in real time and correct the deviation by adjusting the top force distribution or the direction of the cutter head.

[0051] 3. Jacking in the relay room 1) Relay room setting: Relay rooms are installed in sections during long-distance pipe jacking to relay the jacking force.

[0052] 2) Segmented jacking: After completing each section of jacking, start the next relay room to continue advancing.

[0053] 4. Grouting to reduce drag 1) Lubricating mud injection: Inject bentonite mud between the outer wall of the pipe and the soil layer to reduce friction resistance.

[0054] 2) Synchronous grouting: Continuous grouting during the jacking process to fill the gap between the pipe wall and the soil to prevent ground subsidence.

[0055] 5. Pipeline penetration and reception 1) Receiving well preparation: A guide device is installed in the receiving well to ensure accurate penetration of the pipeline.

[0056] 2) Through-hole processing: After the front end of the pipeline enters the receiving well, the boring machine head is removed and the jacking is completed.

[0057] Traffic resumed after final inspection.

[0058] It should be noted that the above content merely illustrates the technical idea of the present invention and cannot be used to limit the scope of protection of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications all fall within the scope of protection of the claims of the present invention.

Claims

1. A quick repair construction method for municipal drainage pipeline collapse in quicksand geology, characterized by: The following steps are involved: (1) Construction preparation and installation of drainage pipes; (2) Install a vertical drainage pump in the well and connect it to the drainage pipe; (3) Soil reinforcement; (4) Construction of pipe jacking working well using reverse method; (5) Rock pipe jacking machine pipe jacking construction.

2. The quick-repair construction method for municipal drainage pipeline collapse in quicksand geology according to claim 1 is characterized by: Construction preparation as described in step (1); including on-site inspection, preparation of materials and tools, installation of drainage pipes, and coordination of power supply, transportation, and waste disposal.

3. The quick repair construction method for municipal drainage pipeline collapse in quicksand geology according to claim 1 is characterized by: Step (2) Install an inverted drainage pipe on the side of the collapsed pipeline and install a vertical drainage pump in the well, as follows: Dig up the collapsed soil and bury an inverted drainpipe beside the collapsed pipeline. The two ends of this pipe are connected to the upstream well and downstream well water pumps. This pipe is parallel to the direction of the collapsed pipeline and is in parallel with the collapsed pipeline. It is used as a drain pipe for drainage operations when repairing the pipeline. After the repair is completed, it will not be dismantled and will be retained as a spare pipeline. If there is a pipeline problem later, it can be used as a temporary inverted drainpipe to convert the temporary drainage facility into a permanent drainage facility, which is convenient for subsequent pipeline inspection and maintenance.

4. The method for rapid repair of a municipal drainage pipeline collapse in quicksand geology according to claim 1 is characterized by: The soil reinforcement described in step (3) is to use high-pressure jet grouting piles to inject cement slurry into the soil layer within 2m of the collapsed pipe to achieve the effect of soil reinforcement. The strength of the reinforced soil can reach 1.5MPa.

5. The method for rapid repair of a municipal drainage pipeline collapse in quicksand geology according to claim 4 is characterized by: The cement slurry uses 42.5 grade ordinary Portland cement. When mixing the mortar, add water first, then add cement. Use a high-speed mixer and the mixing time should be ≥30s. Use an ordinary mixer and the mixing time should be ≥90s. The cement slurry should be used as soon as it is prepared.

6. The method for rapid repair of a municipal drainage pipeline collapse in quicksand geology according to claim 1 is characterized by: The jacking working well described in step (4) adopts a φ2.5 reverse well with a wall thickness of 500mm, a main concrete strength of C30, and a water-resistance grade of P6, as follows: After the construction of the jet-jet pile water-stop curtain is completed, the first layer of earthwork excavation is carried out. During the excavation process, water is pumped out from the well. At the same time, the foundation pit and the surrounding environment are monitored. Parts that cannot be directly excavated by machinery are excavated manually, cleaned, piled, and loaded for transportation. The excavation of the foundation pit is carried out in layers using a long-arm excavator and manual labor. The excavation depth of each layer is 1-1.5m. According to the requirements of the design drawings, a soil pit about the height of a retaining wall section is first excavated at the well location. Then, according to the design requirements, the steel bars are tied and the formwork of the first section is set up. Then, concrete is poured and maintained. Then, the excavation is continued to carry out the construction of the second retaining wall. The above steps are followed until the designed bottom of the well is reached. The first section of the well guard wall is dug to a depth of 1-1.5m. The guard arm is wall-mounted, 500mm beyond the outer wall of the well and 350mm thick. The guard wall template is installed, and the concrete guard wall and wellhead ring beam are poured. One section every two days is considered a construction cycle. To ensure the verticality of the well, the well center position and verticality are checked once after pouring three sections of the guard wall. The verticality correction method is to draw a cross intersection diagonally from the top of the well body as the well center, then use a plumb line to lead into the well as a well center, and use this plumb line to measure the verticality. After the upper concrete is poured and the strength reaches 80% of the design strength, the lower soil is excavated. During the reverse excavation process, if groundwater leakage is found, the following method should be adopted to deal with it: insert a drainage pipe at the defect to drain the water, and then use high-strength cement mortar to seal the defect. After the sealing cement forms a certain strength, close the diversion pipe. If the leakage is more serious and it is difficult to seal it directly, you should first backfill the soil in the pit to block the water flow, and then drill holes outside the pit to inject polyurethane or double liquid slurry to seal the leakage. After sealing, continue excavating downwards.

7. The method for rapid repair of a municipal drainage pipeline collapse in quicksand geology according to claim 1 is characterized by: The pipe jacking process described in step (5) is: Install a guide rail at the bottom of the working well, fix a hydraulic cylinder at the rear end, place the first section of the pipeline on the guide rail, start the hydraulic cylinder to push it into the soil layer, use a tunnel boring machine to excavate and discharge the soil until the front end of the pipeline enters the receiving well, and continue grouting during the jacking process to fill the gap between the pipe wall and the soil to prevent ground subsidence.

8. The method for rapid repair of a municipal drainage pipeline collapse in quicksand geology according to claim 7 is characterized by: Install relay rooms in sections during long distance pipe jacking.

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