In-situ protection construction method for large-diameter shallow-buried pipeline in municipal engineering

Abstract

The invention discloses an in-situ protection construction method for a large-diameter shallow-buried pipeline in municipal engineering. The in-situ protection construction method comprises the steps that S1, preparation before construction is conducted; s2, stirring pile construction; step S3, pipeline monitoring; s4, embedding steel pipes and reinforcing steel bars; s5, detecting the stirring pile; s6, cap beam construction; s7, prefabricating a cover plate; s8, mounting a cover plate; and S9, earthwork backfilling is conducted. The construction operation is flexible, and the project construction period and quality are guaranteed.

Description

Technical Field

[0001] The invention relates to an in-situ protection construction method for a shallowly buried large-diameter pipeline in a municipal engineering project. Background Art

[0002] At present, there are many methods for in-situ protection of pipelines in engineering construction, mainly the suspension method and the portal support method. The main principle of the suspension method is to set a beam on the upper part of the pipeline as a load-bearing body, and use round steel or steel wire rope to suspend the pipeline on the beam to isolate it from the construction soil; the portal support method is to use steel as a beam to support the bottom of the pipeline, and set concrete piers on both sides of the pipeline as beam support points; the above methods are mainly suitable for temporary protection of small and medium diameter pipelines in foundation pit construction. The isolation method is to encapsulate the pipeline. This construction method can be used as a reference for the in-situ protection of shallow buried pipelines with a diameter of more than 1.8m in municipal engineering.

[0003] The pipeline is covered with soil at a depth of 2-3m, with a diameter of 2.4m, and the intersection with the construction area exceeds 18km. If the relocation is adopted, the cost will be high, the construction period will be long, and the impact on the surrounding residents will be great, so the only option is to protect it in situ.

[0004] Therefore, in view of the above problems, a construction method for in-situ protection of large-diameter shallowly buried pipelines in municipal engineering is provided. Summary of the invention

[0005] The purpose of the present invention is to overcome the existing defects and provide an in-situ protection construction method for large-diameter shallow buried pipelines in municipal engineering. The construction operation is more flexible and the construction period and quality of the project are guaranteed.

[0006] The technical solution to achieve the above purpose is:

[0007] A method for in-situ protection of shallowly buried large-diameter pipelines in municipal engineering, comprising:

[0008] Step S1, preparation before construction;

[0009] Step S2, mixing pile construction;

[0010] Step S3, pipeline monitoring;

[0011] Step S4, burying steel pipes and steel bars;

[0012] Step S5, stirring pile detection;

[0013] Step S6, cap beam construction;

[0014] Step S7, prefabrication of cover plate;

[0015] Step S8, cover plate installation;

[0016] Step S9: backfilling.

[0017] Preferably, the step S1 comprises:

[0018] Step S11, cement content determination, before construction, cement mixing pile process test piles should be carried out according to the specification requirements, mainly to determine the cement content, lifting and drilling speed;

[0019] Step S12, pipeline geophysical exploration, determining the position of underground pipelines by manual excavation or geophysical exploration;

[0020] Step S13, monitoring deployment, setting monitoring points near the raw water pipe to monitor the displacement changes of the raw water pipe during construction;

[0021] Step S14, the site is leveled and the site elevation is higher than the pile top elevation.

[0022] Preferably, the step S2 comprises:

[0023] Step S21, equipment selection, selecting single-axis or multi-axis cement mixing piles according to on-site construction conditions;

[0024] Step S22, plane layout, mixing piles adopt bite construction;

[0025] Step S23, stakeout: after the site is leveled to the designed elevation, stakeout is performed on site, and stakes are used to mark the stakes;

[0026] Step S24, the pile driver is in place, and the pile driver is moved to the designated pile position and centered;

[0027] Step S25, slurry preparation, the slurry is prepared with silicate cement and tap water, and the water-cement ratio and cement content are prepared according to the test pile results, wherein the cement slurry is stirred for no less than 5-10 minutes, and does not separate or precipitate, the cement slurry is left to stand for no more than 3 hours, and the cement slurry needs to be sieved before being poured from the mixing tank into the slurry storage tank;

[0028] Step S26, stirring, spraying and sinking. When the drilling rig drills to the designed pile top elevation, stirring, spraying and sinking are performed simultaneously, and the operation of the equipment and the change of the stratum are observed at any time. When the single-axis double-spraying multi-blade drill bit sinks to the designed depth position, drilling is stopped;

[0029] Step S27, stirring and spraying, after drilling to the pile bottom position, keep spraying and stirring at the pile bottom position for more than 10 seconds, change the stirring direction of the drilling rig, lift the drilling rig and keep stirring and spraying to the pile top position;

[0030] Step S28, repeat the stirring and spraying, after the spraying sinks and lifts, carry out the second supplementary spraying and stirring process to complete the "four stirring and four spraying" process for a single pile;

[0031] Step S29, the pile driver moves to a new position. After one pile is constructed, the drilling rig is moved to the next pile position, and the above construction steps are repeated until all the mixing piles are constructed.

[0032] Preferably, in step S3, the pipeline monitoring adopts a pipeline body displacement monitoring station composed of vibrating string sensors; the sensors are buried and laid out before construction, and the displacement of the pipe body is monitored during construction.

[0033] Preferably, step S4 comprises:

[0034] Step S41, steel pipe burial, steel pipe burial begins within 30 minutes after the construction of the mixing pile is completed, and professional equipment is used for on-site transportation and installation. The pre-buried height of the steel pipe is controlled by a laser level, and the verticality of the steel pipe is controlled by a guide frame during the burial of the steel pipe. The pre-buried height deviation of the steel pipe should be controlled within 30 mm, and the horizontal deviation should be controlled within 10 mm;

[0035] Step S42, burying the steel bars, inserting two steel bars into each mixing pile, wherein the upper part of the steel bars is bent.

[0036] Preferably, in step S5, 7 days after the pile is formed, the pile head is excavated shallowly, the uniformity of mixing is visually inspected, and the pile diameter is measured, and the inspection quantity is 5% of the total number of piles; 28 days after the pile is formed, core samples are drilled with a double-tube single-action sampler for compressive strength test, the compressive strength is not less than 0.5 MPa, and the number of inspections is 0.5% of the total number of piles constructed, and is not less than 6.

[0037] Preferably, in step S6, after the mixing pile is tested to be qualified, the pile head is excavated to make the cap beam, which includes:

[0038] Step S61, firstly, the pile head is cleared to the designed elevation, and the steel bars are tied after the foundation is cleaned, and a 10mm wide expansion joint is set in the cap beam every 10m;

[0039] Step S62, pouring concrete after the formwork is reinforced;

[0040] Among them, a rotatable pouring hopper is used for concrete pouring, and the hopper comprises: a mobile base, a rotating ring is fixed on the mobile base, a central shaft is fixed on the mobile base at the center of the rotating ring, a bracket is rotatably mounted on the central shaft, a motor is mounted on the bottom end of the bracket, the output end of the motor is meshed with a gear, and the gear is meshed with the inner gear ring of the rotating ring; a hopper is mounted on the upper end of the bracket, and the discharge port of the hopper is directly opposite to the upper end of the chute;

[0041] Step S63, when vibrating the concrete, insert quickly and pull out slowly, keep the vibration time at 10s-20s each time, and the moving distance is not more than 1.5 times of the vibration action radius;

[0042] Step S64, the cap beam is surface polished before initial setting, and after initial setting, watering and curing are performed at least twice a day according to the local temperature, and the mold is removed after 7 days of curing.

[0043] Preferably, in step S7, the cover plate is prefabricated, and the concrete strength grade is C30;

[0044] The main process flow is: formwork cleaning → steel bar binding → concrete pouring → maintenance → formwork removal;

[0045] The template uses a standardized steel template. The template surface is polished and coated with a release agent before use. The concrete pouring requirements are consistent with the cap beam construction.

[0046] Four lifting rings are buried 20cm away from the end of the plate. The lifting rings are made of steel bars and exposed 10cm. The lifting rings are tied together with the steel bars at the bottom of the plate.

[0047] Preferably, in step S8, a truck crane is used for lifting and transportation of the cover plate, and two layers of oil felt are laid on the inner side of the cap beam before the cover plate is installed, and asphalt is applied on the top of the cover plate and an anti-seepage geomembrane is fully laid.

[0048] Preferably, in step S9, after the cover plate is installed, the earth can be backfilled in layers. The backfill soil uses original plain soil without any foreign matter. The thickness of each backfill layer is not more than 25 cm. A flat plate rammer is used for compaction. And a layer of geogrid is fully laid on the top of the cover plate.

[0049] The beneficial effects of the present invention are as follows: the present invention adopts a protective structure with three sides sealed, thus avoiding the excavation of the soil around the raw water pipe, and retaining a 50cm space between the cover plate and the pipe covering soil, so that the upper load is directly transmitted to the pile foundation, reducing the vibration of the raw water pipe; the innovative use of a pile foundation form in which a seamless steel pipe is inserted into a cement mixing pile greatly reduces the construction cost while meeting the bearing requirements; the present invention can select a large-span pile driver to straddle the raw water pipe to construct the mixing pile, and can also be located on both sides of the raw water pipe to construct the mixing pile, so the construction operation is more flexible; the present invention adopts a prefabricated cover plate on the upper part, which realizes factory standardized production, improves the quality of the project, and saves the time for connecting the processes, saves the project construction period, and ensures the construction period and quality of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a flow chart of a construction method for in-situ protection of shallowly buried large-diameter pipelines in municipal engineering according to the present invention;

[0051] Figure 2 It is a specific flow chart of the preparation before construction in the present invention;

[0052] Figure 3 It is a specific flow chart of the mixing pile construction in the present invention;

[0053] Figure 4It is a specific flow chart of the steel pipe and steel bar burial in the present invention;

[0054] Figure 5 It is a specific flow chart of the cap beam construction in the present invention;

[0055] Figure 6 It is a schematic diagram of the plane layout and construction sequence of the mixing piles in the present invention;

[0056] Figure 7 This is a planar structural diagram of the guide frame for burying steel pipes of the present invention;

[0057] Figure 8 This is a structural elevation diagram of the guide frame for burying steel pipes in the present invention;

[0058] Fig. 9 It is a schematic diagram of the cap beam structure in the present invention. DETAILED DESCRIPTION

[0059] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0060] The present invention will be further described below in conjunction with the accompanying drawings.

[0061] like Figure 1 As shown, a construction method for in-situ protection of large-diameter shallowly buried pipelines in municipal engineering includes:

[0062] Step S1, preparation before construction.

[0063] like Figure 2 As shown, step S1 includes:

[0064] Step S11, cement content determination. Before construction, cement mixing pile process test should be carried out according to the specification requirements, mainly to determine the cement content, lifting and drilling rate; the main process is: soil sample and cement inspection → test pile → pile inspection after reaching 28 days of age → test pile summary.

[0065] Step S12, pipeline geophysical exploration, determines the position of the underground pipeline by manual excavation or geophysical exploration.

[0066] For example, when manual excavation is used, the pipe cover depth should be less than 2m, and the distance between exploration pits should be controlled within the range of 20-30m.

[0067] Step S13, monitoring deployment, setting monitoring points near the raw water pipe to monitor the displacement changes of the raw water pipe during construction.

[0068] Specifically, the sliding rod is made into a clamp shape and connected to the pipeline, and the displacement sensor is fixed in the soil below the pipeline and connected through a heat-treated vibrating wire detection element. As the pulling of the sliding rod causes the increase of the vibrating wire tension, the vibration frequency of the steel wire also changes accordingly, and pipeline monitoring is achieved by measuring the change in the vibration frequency of the steel wire.

[0069] Step S14, the site is leveled and the site elevation should be 10-20 cm higher than the pile top elevation.

[0070] Step S2, mixing pile construction.

[0071] like Figure 3 As shown, step S2 includes:

[0072] Step S21, equipment selection, select single-axis or multi-axis cement mixing piles according to on-site construction conditions.

[0073] Step S22, plane layout, mixing piles are constructed by interlocking, the pile spacing is 0.6m, the plane layout and construction sequence of mixing piles are as follows: Figure 6 As shown, the steel pipes are inserted one by one, that is, according to Figure 6 Steel pipes are inserted into the even-numbered piles, and two pre-buried steel bars are connected in each pile.

[0074] Step S23, stakeout. After the site is leveled and reaches the design elevation, stakeout is performed on site, and the pile positions are marked with wooden stakes. To ensure the accurate position of the embedded steel pipe piles and steel bars, pile guide control is required.

[0075] Step S24, the pile driver is in place, moved to the designated pile position and centered; the height of the machine support legs is adjusted, and the drilling platform is measured with a level ruler to make it horizontal. At the same time, the front and side of the drill pipe are measured with a plumb bob to adjust it to a vertical state before drilling.

[0076] Step S25, slurry preparation, the slurry is prepared with PO 42.5 ordinary Portland cement and tap water, and the water-cement ratio and cement content are prepared according to the test pile results, wherein the cement slurry is stirred for not less than 5-10 minutes, and there is no segregation or precipitation. The cement slurry is left to stand for no more than 3 hours, and the cement slurry must be filtered through a sieve before being poured from the mixing barrel into the slurry storage barrel to prevent the slurry outlet from being blocked, and the slurry storage volume in the slurry storage barrel is controlled to prevent the pile from being broken due to insufficient slurry supply; the cement slurry in the slurry storage barrel should be continuously stirred to prevent unevenness caused by precipitation.

[0077] Step S26, stirring, spraying and sinking. When the drilling rig drills to the designed pile top elevation, stirring, spraying and sinking are carried out simultaneously, and the equipment operation and stratum changes are observed at any time. Drilling is stopped when the single-axis double-jet multi-blade drill bit sinks to the designed depth position.

[0078] Step S27, stirring and spraying, after drilling to the pile bottom position, keep spraying and stirring at the pile bottom position for more than 10 seconds, change the stirring direction of the drilling rig, lift the drilling rig and keep stirring and spraying to the pile top position.

[0079] Step S28, repeat the stirring and spraying. After the spraying sinks and rises, carry out the second supplementary spraying and stirring process to complete the "four stirring and four spraying" process for a single pile. The slurry delivery shall not be interrupted for a long time in the middle. During the pile forming process, if the machine is shut down due to power outages, equipment failures and other reasons, the pile forming process will be interrupted. When the mixer is restarted, the stop surface position should be re-stirred with an overlap length of not less than 50 cm. If the machine is shut down for 3 hours, the slurry delivery pipe should be disassembled and the pipeline should be thoroughly cleaned to prevent the slurry from hardening and clogging the pipe.

[0080] Step S29, the pile driver moves, and after one pile is constructed, the drilling rig is moved to the next pile position, and the above construction steps are repeated until all the mixing piles are constructed. During the displacement of the pile driver, the pile position should be re-measured to control the engagement length of the mixing pile.

[0081] Step S3: pipeline monitoring.

[0082] In the embodiment, the pipeline monitoring adopts a pipeline body displacement monitoring station composed of vibrating string sensors; the sensors are buried and laid out before construction, and the displacement of the pipe body is monitored during construction.

[0083] Step S4, burying steel pipes and steel bars.

[0084] like Figure 4 As shown, step S4 includes:

[0085] Step S41, steel pipe burial, steel pipe burial begins within 30 minutes after the construction of the mixing pile is completed, and professional equipment is used for on-site transportation and installation. The pre-buried height of the steel pipe is controlled by a laser level, and the verticality of the steel pipe is controlled by a guide frame during the burial of the steel pipe. The pre-buried height deviation of the steel pipe should be controlled within 30 mm, and the horizontal deviation should be controlled within 10 mm. The guide frame is as follows: Figure 7 , 8 As shown, specialized equipment includes but is not limited to excavators.

[0086] Step S42, burying the steel bars. Two φ20L ​​steel bars with a length of 1.65m are inserted into each mixing pile. The length of the upper elbow of the steel bar is 15cm, and the length buried in the pile is 1.25m.

[0087] Step S5, mixing pile detection.

[0088] In the embodiment, 7 days after the pile is formed, the pile head is excavated shallowly, the uniformity of mixing is visually inspected, and the pile diameter is measured, and the inspection quantity is 5% of the total number of piles; 28 days after the pile is formed, core samples are drilled with a double-tube single-action sampler for compressive strength test, and the compressive strength is not less than 0.5 MPa. The number of inspections is 0.5% of the total number of piles constructed, and is not less than 6.

[0089] Step S6, cap beam construction.

[0090] like Figure 5 As shown in the figure, after the mixing pile is tested and qualified, the pile head is excavated to make the cap beam. The cap beam structure is as follows Fig. 9 As shown, including:

[0091] Step S61, first clear the pile head to the designed elevation, tie the steel bars after the foundation is cleaned, and set a 10mm wide expansion joint every 10m on the cap beam.

[0092] Step S62, pouring concrete after the formwork is reinforced.

[0093] Step S63, when vibrating the concrete, insert quickly and pull out slowly, keep the vibration time at 10s-20s each time, and the moving distance is not more than 1.5 times of the vibration action radius.

[0094] Step S64, the cap beam is surface polished before initial setting, and after initial setting, watering and curing are performed at least twice a day according to the local temperature, and the mold is removed after 7 days of curing.

[0095] Step S7: prefabrication of cover plates.

[0096] In the embodiment, the cover plate is prefabricated, and the concrete strength grade is C30, wherein the cover plate structure size is 5.2m×1m×0.45m;

[0097] The main process flow is: formwork cleaning → steel bar binding → concrete pouring → maintenance → formwork removal;

[0098] The template uses a standardized steel template. The template surface is polished and coated with a release agent before use. The concrete pouring requirements are consistent with the cap beam construction.

[0099] Four lifting rings are buried 20cm away from the end of the plate. The lifting rings are made of φ20 steel bars and exposed 10cm. The lifting rings are tied together with the steel bars at the bottom of the plate.

[0100] Step S8, cover plate installation.

[0101] In the embodiment, a truck crane is used for lifting and transportation of the cover plate, and two layers of oil felt are laid on the inner side of the cap beam before the cover plate is installed, and asphalt is applied on the top of the cover plate and an anti-seepage geomembrane is fully laid.

[0102] Step S9: backfilling.

[0103] In the embodiment, after the cover plate is installed, the earth can be backfilled in layers. The backfill soil uses original plain soil without any debris. The thickness of each backfill layer is not more than 25 cm, and a flat plate rammer is used for compaction. A layer of geogrid is fully laid 50 cm from the top of the cover plate to increase the stability of the backfill soil and prevent it from cracking.

[0104] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A construction method for in-situ protection of large-diameter shallowly buried pipelines in municipal engineering, characterized in that: include: Step S1, preparation before construction; Step S2, mixing pile construction; Step S3, pipeline monitoring; Step S4, burying steel pipes and steel bars; Step S5, stirring pile detection; Step S6, cap beam construction; Step S7, prefabrication of cover plate; Step S8, cover plate installation; Step S9: backfilling.

2. The in-situ protection construction method for large-diameter shallow buried pipelines in municipal engineering according to claim 1 is characterized in that: The step S1 comprises: Step S11, cement content determination, before construction, cement mixing pile process test piles should be carried out according to the specification requirements, mainly to determine the cement content, lifting and drilling speed; Step S12, pipeline geophysical exploration, determining the position of underground pipelines by manual excavation or geophysical exploration; Step S13, monitoring deployment, setting monitoring points near the raw water pipe to monitor the displacement changes of the raw water pipe during construction; Step S14, the site is leveled and the site elevation is higher than the pile top elevation.

3. The in-situ protection construction method for large-diameter shallow buried pipelines in municipal engineering according to claim 1 is characterized in that: The step S2 comprises: Step S21, equipment selection, selecting single-axis or multi-axis cement mixing piles according to on-site construction conditions; Step S22, plane layout, mixing piles adopt bite construction; Step S23, stakeout: after the site is leveled to the designed elevation, stakeout is performed on site, and stakes are used to mark the stakes; Step S24, the pile driver is in place, and the pile driver is moved to the designated pile position and centered; Step S25, slurry preparation, the slurry is prepared with silicate cement and tap water, and the water-cement ratio and cement content are prepared according to the test pile results, wherein the cement slurry is stirred for no less than 5-10 minutes, and does not separate or precipitate, the cement slurry is left to stand for no more than 3 hours, and the cement slurry needs to be sieved before being poured from the mixing tank into the slurry storage tank; Step S26, stirring, spraying and sinking. When the drilling rig drills to the designed pile top elevation, stirring, spraying and sinking are performed simultaneously, and the operation of the equipment and the change of the stratum are observed at any time. When the single-axis double-spraying multi-blade drill bit sinks to the designed depth position, drilling is stopped; Step S27, stirring and spraying, after drilling to the pile bottom position, keep spraying and stirring at the pile bottom position for more than 10 seconds, change the stirring direction of the drilling rig, lift the drilling rig and keep stirring and spraying to the pile top position; Step S28, repeat the stirring and spraying, after the spraying sinks and lifts, carry out the second supplementary spraying and stirring process to complete the "four stirring and four spraying" process for a single pile; Step S29, the pile driver moves to a new position. After one pile is constructed, the drilling rig is moved to the next pile position, and the above construction steps are repeated until all the mixing piles are constructed.

4. The in-situ protection construction method for large-diameter shallow buried pipelines in municipal engineering according to claim 1 is characterized in that: In step S3, the pipeline monitoring uses a pipeline body displacement monitoring station composed of vibrating string sensors; the sensors are buried and laid out before construction, and the displacement of the pipeline body is monitored during construction.

5. The in-situ protection construction method for large-diameter shallowly buried pipelines in municipal engineering according to claim 1 is characterized in that: The step S4 comprises: Step S41, steel pipe burial, steel pipe burial begins within 30 minutes after the construction of the mixing pile is completed, and professional equipment is used for on-site transportation and installation. The pre-buried height of the steel pipe is controlled by a laser level, and the verticality of the steel pipe is controlled by a guide frame during the burial of the steel pipe. The pre-buried height deviation of the steel pipe should be controlled within 30 mm, and the horizontal deviation should be controlled within 10 mm; Step S42, burying the steel bars, inserting two steel bars into each mixing pile, wherein the upper part of the steel bars is bent.

6. The in-situ protection construction method for large-diameter shallow buried pipelines in municipal engineering according to claim 1 is characterized in that: In step S5, 7 days after the pile is formed, the pile head is excavated shallowly, the uniformity of mixing is visually inspected, and the pile diameter is measured, and the inspection quantity is 5% of the total number of piles; 28 days after the pile is formed, core samples are drilled with a double-tube single-action sampler for compressive strength test, the compressive strength is not less than 0.5MPa, and the number of inspections is 0.5% of the total number of piles under construction, and is not less than 6.

7. The in-situ protection construction method for large-diameter shallow buried pipelines in municipal engineering according to claim 1 is characterized in that: In the step S6, after the mixing pile is tested and qualified, the pile head is excavated to make the cap beam, which includes: Step S61, firstly, the pile head is cleared to the designed elevation, and the steel bars are tied after the foundation is cleaned, and a 10mm wide expansion joint is set in the cap beam every 10m; Step S62, pouring concrete after the formwork is reinforced; Step S63, when vibrating the concrete, insert quickly and pull out slowly, keep the vibration time at 10s-20s each time, and the moving distance is not more than 1.5 times of the vibration action radius; Step S64, the cap beam is surface polished before initial setting, and after initial setting, watering and curing are performed at least twice a day according to the local temperature, and the mold is removed after 7 days of curing.

8. The in-situ protection construction method for large-diameter shallowly buried pipelines in municipal engineering according to claim 1 is characterized in that: In step S7, the cover plate is prefabricated, and the concrete strength grade is C30; The main process flow is: formwork cleaning → steel bar binding → concrete pouring → maintenance → formwork removal; The template uses a standardized steel template. The template surface is polished and coated with a release agent before use. The concrete pouring requirements are consistent with the cap beam construction. Four lifting rings are buried 20cm away from the end of the plate. The lifting rings are made of steel bars and exposed 10cm. The lifting rings are tied together with the steel bars at the bottom of the plate.

9. The in-situ protection construction method for large-diameter shallow buried pipelines in municipal engineering according to claim 1 is characterized in that: In step S8, the cover plate is hoisted and transported using a truck crane, and two layers of oil felt are laid on the inner side of the cap beam before the cover plate is installed, and asphalt is applied on the top of the cover plate and an anti-seepage geomembrane is fully laid.

10. The in-situ protection construction method for large-diameter shallow buried pipelines in municipal engineering according to claim 1 is characterized in that: In step S9, after the cover plate is installed, the earth can be backfilled in layers. The backfill soil uses original plain soil without any foreign matter. The thickness of each backfill layer is not more than 25 cm. A flat plate rammer is used for compaction. A layer of geogrid is fully laid on the top of the cover plate.

Images