Construction method suitable for excavation protection of water conveying pipeline

Abstract

The invention relates to the field of pipeline excavation, in particular to a construction method suitable for excavation protection of a water conveying pipeline. Comprising the steps of pouring of supports at the two ends of the pipeline, excavation of the two sides of the pipeline, placement of bottom longitudinal I-shaped steel and the like, a firm pipeline protection system is formed after the method is completed, and excavation of the lower portion of the protected pipeline and other construction work can be conducted after the method is completed. Compared with traditional pipe jacking or shield construction, the conditions of sedimentation, pipeline damage and the like caused by excavation below the pipeline are avoided, the affected pipe joints are exposed under the view field, and whether leakage or deformation occurs or not can be obviously seen. Particularly, when multiple sections of socket pipes exist in an existing pipeline and excavation is conducted below the pipeline, the pipeline is firmly protected, the bearing capacity is large, and the rigidity is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pipeline excavation, in particular to a construction method suitable for water pipeline excavation protection. BACKGROUND

[0002] After consulting relevant information, there is no protection for pipelines during construction under the pipeline, but the pipe jacking or shield construction is used to reduce the impact on existing pipelines.

[0003] (1) The pipe jacking construction process is shown in Figure 1

[0004] 1) The initial jacking of the pipe jacking machine is one of the key links of pipe jacking construction, which mainly includes: pre-hole ground water reduction and soil reinforcement, setting up the starting base of the pipe jacking machine, assembling and debugging the pipe jacking machine unit, installing the sealing expansion ring, testing the operation of the pipe jacking machine, pressurizing the penetration operation surface of the pipe jacking machine, and jacking, etc.

[0005] 2) Trial jacking

[0006] The first 100 cm of the pipe jacking machine is used as a trial jacking section. Through the trial jacking section, the operation method of the pipe jacking machine in the stratum of the project, the adjustment and control method of the jacking parameters of the pipe jacking machine, and the grouting process of the thixotropic mud are mastered. The ground surface heave and ground displacement are tested, and the stratum displacement law under different jacking parameter conditions and the impact of construction on the ground environment are analyzed in detail in a timely manner. The construction parameters are adjusted in a timely manner to ensure the safe and smooth construction of the whole section of the pipe.

[0007] 3) Normal jacking

[0008] After the trial jacking is completed, the normal jacking construction can be carried out. The cutter head of the pipe jacking machine rotates and cuts the soil on the contact surface. The cut soil enters the soil bin and is transported to the soil car by the screw conveyor. Then the soil is transported to the wellhead by the soil car and hoisted out of the wellhead by the crane.

[0009] After the jacking of a section of pipe is completed, the main jack is retracted, the next section of pipe is placed, the waterproof device of the pipe is installed and inspected, the top iron is installed on the pipe socket, and a layer of corrosion-resistant material and lubricant is applied to the outer surface of the pipe. Then continue to jacking. When the main jacking jack is extended to the length of a section of pipe, retract the jack, place the pipe and top iron, and continue jacking. Repeat this process until a top section is completed.

[0010] 4) Thixotropic mud

[0011] ​In pipe jacking construction, according to the different pipe diameter, the diameter of the subsequent pipe material is generally 20mm smaller than the diameter of the pipe jacking machine, and there is a gap between the pipe and the surrounding soil; deviation correction produces extrusion on one side of the soil, and the other side also forms a gap due to stress release. Therefore, there are many gaps in the track of pipe jacking. The role of slurry in pipe jacking construction is: first, to reduce the frictional resistance between the pipe and the outer wall and reduce the jacking resistance; in pipe jacking construction, we use thixotropic mud to form a mud sleeve around the pipe to reduce the friction between the pipe outer wall and the stratum, which is a crucial technical measure in the process of pipe jacking construction. Secondly, the supporting role, under the grouting pressure, reduces the deformation of the soil, makes the pipe hole stable, and controls the ground settlement. Thirdly, the filling role, the slurry fills the gap between the pipe and the soil during construction.

[0012] (2) The shield construction process is shown in Figure 2

[0013] 1) Temporary sealing device of hole portal

[0014] During the starting process of the shield, the hole portal and the shield shell will form an annular building gap. In order to prevent the mud from flowing into during the starting process, affecting the establishment of mud pressure on the excavation face, the stability of the soil on the excavation face, and the construction in the working well and the shield, a sealing device with good performance must be set to ensure the establishment of initial mud balance and construction safety.

[0015] The temporary sealing of the hole portal is arranged on the pre-buried steel plate of the hole portal ring in a box structure, 2 rows of rubber plate and folding plate are installed in the box, and special mud (or oil) is injected between the 2 rows of rubber plate to enhance the sealing effect of the box. In order to enhance the ability to resist mud pressure, 3 rows of steel wire brushes are installed in the hole portal ring, and oil is injected between the steel brushes to enhance the sealing.

[0016] The hole portal sealing construction is carried out in two steps, the first step is to do the embedding work of the hole portal embedded part during the construction of the lining wall in the working well; the second step is to install the hole portal sealing pressure plate and rubber curtain cloth plate and other sealing devices in time before the formal starting or arrival of the shield.

[0017] The hole portal sealing construction is carried out in two steps, the first step is to do the embedding work of the hole portal embedded part during the construction of the lining wall in the working well; the second step is to install the hole portal sealing pressure plate and rubber curtain cloth plate and other sealing devices in time before the formal starting or arrival of the shield.

[0018] 2) Shield construction

[0019] The receiving end of the HH2 shield well is a sleeve valve pipe grouting reinforcement, the spacing is 1.2m x 1.2m, and the soil reinforcement thickness is 14.5m.

[0020] A construction process

[0021] ​Bore → drill → pouring sleeve material → sleeve valve pipe → grouting → hole construction

[0022] B construction steps

[0023] a Bore: On-site use of total station to measure hole arrangement and make obvious marks.

[0024] b Drilling: Drilling construction uses φ90-110mm drill bit mud retaining wall drilling, which is pushed out step by step from the center to achieve a drilling depth of 9m. The deviation of drilling perpendicularity should not be greater than 3%.

[0025] c Casting shell material

[0026] Sleeve material usage (m 3 ) = 1.3 * π * (drilling radius 2 - sleeve valve pipe radius 2) * grouting segment height; mix ratio is cement: clay: water = 1:0.5:1.2 (weight ratio); lower the drill pipe to the hole bottom, and use the mud pump to inject the mixed sleeve material into the hole through the drill pipe until the top of the hole.

[0027] d Lower sleeve valve pipe

[0028] Insert the prepared PVC plastic sleeve valve pipe into the hole bottom, and try to make the sleeve valve pipe vertical and located in the center of the hole. On the plastic pipe, 8-10 small holes with a diameter of 8-10mm are opened at intervals of 35mm, and the position of each small hole is staggered.

[0029] e Grouting

[0030] According to the hole forming sequence, after the sleeve material and solid pipe grouting reach a certain strength (usually after three days), lower the double-piston 6-point grouting steel pipe from the sleeve valve pipe to the grouting position from top to bottom. The lower part has been grouted, and the cross-sectional length is 0.5cm.

[0031] During the grouting process, observe the exhaust, water, grout, and escape of adjacent grouting holes, and make timely records. If there is grouting or wire drawing phenomenon in the surrounding grouting holes, stop grouting, and then grout after 12 hours. If the surrounding grouting holes still have no reaction, the grouting amount is too large to exceed the self-volume, the "intermittent quantitative, sequential grouting method" should be used to control the excessive loss of grout. Make good grouting record original, and timely submit to the owner and supervision unit for approval and signature.

[0032] 3) Mud balance establishment

[0033] Before mud balance shield construction, prepare mud with certain specific gravity, viscosity, and sufficient amount for shield circulation. Before the shield starts, prepare the grout needed for construction in the mud tank, and the first grouting amount is 600m 3 .

[0034] The shield establishes slurry balance at the starting hole, and the hole portal should have good water stopping conditions, that is, preventing a large amount of slurry from flowing into the well during the establishment of slurry balance, so as to ensure the water pressure balance and stability of the slurry chamber and the sealing effect of the temporary sealing device of the hole portal. The temporary sealing device of the hole portal can withstand lower slurry pressure due to the influence of uneven building gaps of the hole portal, and the slurry pressure of the slurry chamber is controlled to be not more than the water pressure of the middle height of the shield under the condition of not affecting the normal transportation balance of the slurry system. With the increase of the advancing distance, the slurry pressure is gradually increased after the hole portal section is synchronously grouted and supplemented, and the normal slurry balance control is achieved.

[0035] The above two construction methods are to reduce the settlement of the upper soil body by drilling from the lower part and synchronously grouting by mechanical equipment, but the disturbance degree of the upper pipeline by this method is not obvious. If the slurry balance pressure is not controlled well during the process of the pipe jacking or shield underpass construction, ground subsidence, pipe joint breakage and other risks may occur.

[0036] Moreover, after the pipe jacking or shield construction is completed, the upper soil body may be extruded or settled due to the post-grouting pressure, which will affect the running water pipeline or cause damage, water leakage and other risks.

[0037] To solve the problem of avoiding settlement deformation or even damage to the pipeline during the construction under the pipeline, the construction method is proposed. SUMMARY

[0038] To solve the problem of the prior art, the application provides a construction method suitable for water pipeline excavation protection.

[0039] To achieve the above purpose, the application adopts the following technical scheme:

[0040] A construction method suitable for water pipeline excavation protection, comprising the following steps:

[0041] (1) Pouring of both ends of the pipeline support:

[0042] First, the both ends of the pipeline to be protected are excavated, and if the pipeline to be protected is a socket pipe, the middle position of the socket pipe section is selected as the pipeline support position. After excavation, concrete is poured to the bottom of the longitudinal I-steel position;

[0043] (2) Excavation of both sides of the pipeline:

[0044] The both sides of the pipeline are excavated manually, and the pipe body and the soil body at the bottom of the pipeline should not be disturbed during the excavation process. The both sides of the pipeline are excavated to the bottom of the longitudinal channel steel;

[0045] (3) Place the bottom longitudinal I-beam:

[0046] Place two bottom longitudinal channel steels on the concrete of the two end supports and level them. Leveling can be achieved by welding thin steel plates to the bottom I-beams.

[0047] (4) Weld the bottom transverse I-beam, the gusset plate and the angle steel as the excavation progresses:

[0048] Excavate from one end of the support to the other end for the protected pipeline. Every 30-70 cm of the excavated pipeline, insert the bottom transverse I-beam into the bottom of the pipeline and weld it to the bottom longitudinal I-beam. Fill the gap between the bottom transverse I-beam and the pipeline with the steel gusset plate to make it compact.

[0049] (5) Weld the vertical and inclined I-beams:

[0050] After the bottom transverse I-beam, the steel gusset plate and the angle steel are completed for every excavated section of the pipeline, weld the vertical I-beams and weld the inclined I-beams between the two vertical I-beams. The inclined I-beams form a stable triangular structure with the bottom longitudinal I-beam and the vertical I-beams.

[0051] Continue the cycle of steps (4) and (5) until the entire pipeline support is completed.

[0052] (6) Weld the top longitudinal I-beam and the top transverse channel steel:

[0053] Place the top longitudinal I-beams on both sides of the pipeline on top of the vertical I-beams and weld them firmly. Then place the top transverse channel steel on top of the top longitudinal I-beams and weld it. In this way, a firm support and protection system is formed to enclose the pipeline inside.

[0054] (7) Pour the second phase of concrete for the support:

[0055] Chisel the support concrete and pour concrete onto the top transverse channel steel. Thus, the protection of the entire pipeline is completed.

[0056] The construction method for protecting the water pipeline excavation places an angle steel on each side of the pipeline and welds it to the bottom transverse I-beam.

[0057] Compared with the prior art, the beneficial effects of the invention are as follows: After the invention is completed, a firm pipeline protection system is formed. After completion, the protected pipeline can be excavated below and other construction operations can be carried out. Compared with traditional pipe jacking or shield construction, the invention avoids the occurrence of settlement and pipeline damage when excavating below the pipeline. The affected pipe sections are exposed to view, and whether they leak or deform can be clearly seen. Especially when there are multiple section of socket pipes in the existing pipeline, the pipeline protection is firm when excavating below the pipeline, the bearing capacity is large, and the stiffness is strong. BRIEF DESCRIPTION OF DRAWINGS

[0058] Other features, objects, and advantages of the application will become apparent from a reading of the detailed description of non-limiting embodiments thereof, taken in conjunction with the following drawings.

[0059] Figure 1 is a process flow chart of pipe jacking construction of the present application.

[0060] Figure 2 is a process flow chart of shield construction of the present application.

[0061] Figure 3 is a process flow chart of construction of the present application.

[0062] Figure 4 is a structural schematic of the present application Figure 1 .

[0063] Figure 5 is a structural schematic of the present application Figure 2 .

[0064] Figure 6 is a plane schematic of the cross-penetrating section of the present application.

[0065] Figure 7 is a longitudinal section schematic of the cross-penetrating section of the present application.

[0066] Figure 8 is a pipe bracket foundation elevation view of the present application.

[0067] Figure 9 is a pipe bracket foundation plan view of the present application.

[0068] Figure 10 is a pipe bracket section view of the present application.

[0069] Figure 11 is a pipe bracket top view of the present application.

[0070] Figure 12 is a pipe bracket bottom view of the present application. DETAILED DESCRIPTION

[0071] The present application is further described in detail by the following examples, which are only used to illustrate the present application and do not limit the scope of the present application.

[0072] A construction method suitable for water pipeline excavation protection, comprising the following steps:

[0073] (1) Pouring of pipe end supports:

[0074] First, select the two ends of the pipeline to be protected for excavation, if the pipeline to be protected is a socket pipe, select the middle position of the socket pipe section as the pipe support position; after excavation, pour concrete to the bottom of the longitudinal I-beam 2 bottom position.

[0075] (2) Excavation on both sides of the pipeline:

[0076] Excavation on both sides of the pipeline is carried out manually, and the pipeline body and the soil at the bottom of the pipeline should not be disturbed during the excavation process. The excavation on both sides of the pipeline is carried out to the bottom of the longitudinal channel steel;

[0077] (3) Place the bottom longitudinal I-beam 2:

[0078] Place two bottom longitudinal channel steels on the concrete of the support at both ends and level them. Leveling can be achieved by welding thin steel plates to the bottom I-beam.

[0079] (4) Weld the bottom transverse I-beam, steel pad, and angle steel as the excavation progresses:

[0080] Excavate the pipeline from one end of the support to the other end. Every 30-70 cm of excavated pipeline, insert the bottom transverse I-beam 3 into the bottom of the pipeline (there is a small gap between the bottom transverse I-beam 3 and the pipeline) and weld it with the bottom longitudinal I-beam 2. Fill the gap between the bottom transverse I-beam 3 and the pipeline with steel pads 4 to make it dense. Place an angle steel 5 on each side of the pipeline and weld it with the bottom transverse I-beam 3. This angle steel 5 is used to stabilize the pipeline and prevent it from shifting to both sides.

[0081] (5) Weld vertical and inclined I-beams:

[0082] After completing the bottom transverse I-beam 3, steel pad 4, and angle steel 5 for every excavated section of the pipeline, weld the vertical I-beam 6, and use the inclined I-beam 7 between the two vertical I-beams 6. The inclined I-beam 7 forms a stable triangular structure with the bottom longitudinal I-beam 2 and the vertical I-beam 6.

[0083] Continue the cycle of steps (4) and (5) until the entire pipeline support is completed.

[0084] (6) Weld the top longitudinal I-beam 8 and the top transverse channel steel 9:

[0085] Place the top longitudinal I-beam 8 on both sides of the pipeline on top of the vertical I-beam 6 and level it firmly, then place the top transverse channel steel 9 on top of the top longitudinal I-beam 8 and weld it. This forms a firm support and protection system that encloses the pipeline inside;

[0086] (7) Pouring of the second-stage concrete of the support:

[0087] Perform concrete chiseling on the support and pour concrete onto the top transverse channel steel 9. This completes the protection of the entire pipeline.

[0088] The scheme is applied to the intersection of the construction BG0+684.778 of the north main pipe and its branch pipe of the Baise Reservoir Irrigation Area Project in the northwest of Guangxi and the water supply pipeline in Tianyang District. According to the field measurement, the influence length of the water supply pipeline on the main pipe is 16.34 m, and the pipeline intersects with the main pipe at an angle of 47°. The water supply pipeline is linearly arranged in the plane and longitudinal direction of the main pipe. The pipe material of the water supply pipeline at this point is PCCP pipe, the nominal inner diameter of the pipeline is DN = 2.0 m, the design pressure of the pipeline is 1.6 MPa, the working pressure is 1.2 MPa, and the test pressure is 1.44. The pipe diameter of the water supply pipeline in Tianyang District at this point is 0.8 m, and the burial depth is about 2 m.

[0089] The crossing method is that the north main pipe of the Baise Reservoir Irrigation Area Project in the northwest of Guangxi crosses under the water supply pipeline in the Tianyang District. As shown in Figure 6 、 7 ,

[0090] (1) Measure and release the line, and release the crossing center axis with the theodolite according to the control pile position given by the design, and determine the crossing center pile. The construction belt boundary line pile is painted with white lime. During the construction operation, the pile position should be according to the design, and the artificial exploratory excavation is adopted until the position and direction of the pipeline are completely determined. At the same time, the materials and resources such as the water supply pipeline protection support, temporary support of the pipe trench, etc. are prepared.

[0091] (2) First excavate the water supply pipeline bracket support at both ends, which is 2*2*1.5 m in size, and pour the support with C20 concrete.

[0092] (3) Excavate the water supply pipeline on both sides to the bottom. After artificial excavation to the bottom of the buried water supply pipeline, the I25 H-shaped steel is used as the cross beam bracket (the longitudinal H-shaped steel at the bottom) to support the water supply pipeline. A part of the cross beam bracket bottom is excavated manually, and then the I14 H-shaped steel (the transverse H-shaped steel at the bottom) is used to connect the cross beam bracket at an interval of 1 m. Then, the 3 cm thick steel plate pad 4 is used at the bottom of the water supply pipeline, and the 125# angle steel 5 is used to fix the water supply pipeline on both sides. The cross beam is connected into a whole by repeating the above operation. The 10# channel steel is used to arrange the truss in a broken line type with an interval of 1 m between the cross beams. The vertical H-shaped steel 6 and the inclined H-shaped steel 7 are both 10# channel steel. The truss is composed of the vertical H-shaped steel 6 and the inclined H-shaped steel 7. The vertical H-shaped steel 6 and the inclined H-shaped steel 7 are connected by the stiffener. The 10# channel steel (the transverse channel steel 9 at the top) is used at the top of the bracket (the longitudinal H-shaped steel at the bottom) in a broken line type with an interval of 2 m at an angle of 45°. After the protection steel support is completed to ensure the safety and stability of the water supply pipeline, the artificial layered excavation is continued to the design pipe trench bottom elevation. During the excavation process, the steel sheet pile is used for temporary support of the pipe trench.

[0093] (4) using steel support 4 I25 H-beam as a cross beam bracket (bottom longitudinal H-beam 2), each side of the groove has 2; between the cross beam bracket two sides using 10# channel steel, 1m spacing line type arrangement into truss (vertical H-beam 6 and inclined H-beam 7); cross beam bracket bottom using I14 H-beam, 1m spacing arrangement; cross beam bracket top using 10# channel steel, 45° angle 2m spacing line type arrangement.

[0094] At the upstream and downstream positions of the intersection, the PCCP pipeline is lifted using a gantry crane, the pipeline port is required to be at least 3m away from the water supply pipeline, then slowly hoisted into the trench, avoiding the pipeline from swinging and colliding with the water supply pipeline. After the pipeline enters the trench, the pipeline is moved parallel to the installation point for installation, after installation, manual sand cushion layer and earthwork backfilling are performed around the pipeline. All steel supports of the bracket are reserved, C20 concrete is poured to the middle of the water supply pipeline (the height is confirmed on site), then the earthwork backfilling is continued to cover the water supply pipeline to the original ground, and the original landform is restored.

[0095] Although the specific embodiments of the present application are described above, those skilled in the art should understand that this is only an example, the protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present application, and these changes and modifications all fall within the protection scope of the present application.

Claims

1. A construction method suitable for excavation protection of water pipelines, characterized in that: The steps include: (1) Casting of supports at both ends of the pipeline: First, select both ends of the pipe to be protected for excavation. If the pipe to be protected is a bell-and-spigot pipe, select the middle of the bell-and-spigot joint as the pipe support location. After the excavation is completed, pour concrete to the bottom of the longitudinal I-beam at the bottom. (2) Excavation on both sides of the pipeline: Excavation on both sides of the pipeline shall be carried out manually. The pipe body and the soil at the bottom of the pipeline shall not be disturbed during the excavation process. The excavation on both sides of the pipeline shall be carried out to the bottom of the bottom longitudinal channel steel; (3) Place the bottom longitudinal I-beam: Place two bottom longitudinal channel steels on the concrete supports at both ends and level them. The leveling can be done by welding thin steel plates to the bottom I-beams. (4) Welding the bottom transverse I-beam, pad and angle steel as excavation progresses: For the protected pipeline, excavate from one end of the support to the other end. Every 30-70cm of the excavated pipeline, insert the bottom horizontal I-beam into the bottom of the pipeline and weld it to the bottom longitudinal I-beam. Fill the gap between the bottom horizontal I-beam and the pipeline with a steel pad to fill it tightly. (5) Welding vertical and oblique I-beams: After each section of pipeline is excavated and the bottom horizontal I-beam, steel pad and angle steel are completed, the vertical I-beam is welded, and the two vertical I-beams are welded with oblique I-beams. The oblique I-beam, the bottom longitudinal I-beam and the vertical I-beam form a stable triangular structure. Continue to cycle through steps (4) and (5) until the entire pipeline support is completed; (6) Welding top longitudinal I-beam and top transverse channel steel: Place the top longitudinal I-beams on both sides of the pipeline on top of the vertical I-beams, level them, and weld them firmly. Then place the top transverse channel steel on top of the top longitudinal I-beams and weld them, thus forming a firm support and protection system that surrounds the pipeline. (7) Second phase concrete pouring of support: The support concrete is roughened and concrete is poured onto the top transverse channel steel, thus completing the protection of the entire pipeline.

2. The construction method for excavation protection of water pipelines according to claim 1, characterized in that: Place an angle steel on each side of the pipe and weld it to the horizontal I-beam at the bottom.

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