High underground water level groove pipeline construction method

Abstract

The invention is suitable for the technical field of municipal pipeline engineering, and provides a high underground water level groove pipeline construction method which comprises the following steps: step 1, laying steel plates on two sides of an excavated groove, and laying tracks on the steel plates in parallel to form a track-steel plate foundation; step 2, mounting an assembling hopper on a track, erecting a gantry crane above the track, and connecting the gantry crane with the assembling hopper through a tractor to construct a three-dimensional mobile operation platform above the groove; 3, an arc-shaped pipeline sliding groove is formed in the assembling hopper, a gantry crane is used for hoisting the pipeline to the assembling hopper, and assembling of the pipeline is completed on the ground; 4, the assembling hopper is dragged by a tractor to move to the position above the groove, the assembled pipeline is guided by a pipeline sliding groove to stably slide into the groove, and the assembled pipeline is connected with the laid pipeline to complete laying; 5, the step 3 and the step 4 are repeated until all the long-distance pipelines are laid; the method is suitable for groove construction in high-underground-water-level complex geological scenes.

Description

Technical Field

[0001] This invention relates to the field of municipal pipeline engineering technology, specifically a method for constructing trench pipelines at high groundwater levels. Background Technology

[0002] In municipal pipeline construction, trench excavation is a core preliminary step in pipeline laying. When the construction site has a high groundwater level, traditional trench pipeline construction methods face two major challenges:

[0003] 1. After trench excavation, groundwater is prone to seepage, which leads to water accumulation and soil softening in the trench. This not only increases the risk of trench collapse, but also requires underwater pipeline connection operations, which poses safety hazards such as drowning and machinery overturning. In addition, the efficiency of underwater operations is only less than 60% of that of ground operations.

[0004] 2. For long-distance (usually over 500 meters) pipeline construction, traditional methods rely on temporary support platforms in the trench for pipeline assembly. Due to the influence of water accumulation and soft soil, the stability of the platform is poor, making it difficult to guarantee the accuracy of pipeline assembly (such as axis deviation and joint sealing), resulting in a rework rate as high as 15% to 20%.

[0005] To address the aforementioned issues, existing technologies often employ a "large-scale wellpoint dewatering + trench sheet pile support" approach. However, this approach requires additional investment in dewatering equipment, support materials, and labor, increasing construction costs by more than 30%. Furthermore, the dewatering process can easily trigger ground subsidence in the surrounding area, posing a threat to the safety of nearby buildings.

[0006] Therefore, in view of the above situation, there is an urgent need to provide a construction method for trench pipelines with high groundwater levels to overcome the shortcomings in current practical applications. Summary of the Invention

[0007] The purpose of this invention is to provide a method for constructing trench pipelines at high groundwater levels, effectively solving the problems mentioned in the background art.

[0008] This invention is implemented as follows: a method for constructing trench pipelines at high groundwater levels, the method comprising the following steps:

[0009] Step 1: Lay steel plates on both sides of the excavated trench, and lay tracks parallel to the steel plates to form a track-steel plate foundation;

[0010] Step 2: Install the assembly truck bed on the track, erect a gantry crane above the track, and connect the gantry crane to the assembly truck bed through a tractor to construct a three-dimensional mobile work platform above the trench;

[0011] Step 3: Install the arc-shaped pipe chute on the assembly truck bed, and use a gantry crane to lift the pipe onto the assembly truck bed to complete the pipe assembly on the ground;

[0012] Step 4: Move the assembly truck bed to the top of the trench using a tractor, and guide the assembled pipes smoothly into the trench through the pipe chute to connect with the already laid pipes to complete the laying process.

[0013] Step 5: Repeat steps 3 and 4 until the entire long-distance pipeline is laid.

[0014] As a further aspect of the present invention: in step 1, the steel plate has a thickness of not less than 16mm and is made of Q235B material.

[0015] As a further aspect of the present invention: in step 1, the track is a QU70 light rail, and the track spacing matches the wheel track of the assembled truck, with an error of ≤5mm.

[0016] As a further aspect of the present invention: in step 1, the steel plate is laid 1.5 to 2 meters away from the edge of the trench, and the coverage area of ​​the steel plate is consistent with the pipeline construction length.

[0017] As a further aspect of the present invention: in step 2, the load capacity of the assembly truck bed is not less than 50t, and the bottom of the assembly truck bed is provided with track wheels adapted to the track.

[0018] As a further aspect of the present invention: in step 2, the lifting capacity of the gantry crane is not less than 30t, the traveling direction is parallel to the track, and the span of the gantry crane covers the trench and the tracks on both sides.

[0019] As a further aspect of the present invention: in step 3, the curvature of the pipe groove matches the outer diameter of the pipe with an error of ≤3mm, and the inner wall of the pipe groove is provided with a wear-resistant rubber layer.

[0020] As a further aspect of the present invention: in step 3, the assembly of the pipes on the assembly truck bed includes pipe axis alignment and interface sealing operations.

[0021] As a further aspect of the present invention: In step 4, after the assembly truck bed is moved above the trench, the height is adjusted by hydraulic outriggers so that the distance between the outlet end of the pipe chute and the inner padding layer of the trench is ≤100mm.

[0022] As a further aspect of the present invention: in step 4, a buffer device is set at the outlet end of the pipe trough during the pipe sliding process, and the pipe is manually guided to move in the trough.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] Reduce construction costs, specifically by eliminating the need for large-scale dewatering equipment and trench support materials, resulting in a cost reduction of 25% to 35%.

[0025] To improve work efficiency, the following measures are taken: ground assembly + chute-guided laying, avoiding underwater docking procedures, thus improving construction efficiency by more than 40%.

[0026] To ensure construction safety, the following measures are taken: no work is carried out in trenches throughout the entire process, completely avoiding safety hazards such as collapses and drowning, and reducing the accident rate to 0.

[0027] To ensure laying accuracy, the following measures are taken: the track-steel plate foundation ensures the stability of the assembled truck bed; the chute guides the pipe to avoid deviation; the axis deviation is controlled within ±2mm; and the interface sealing qualification rate reaches 100%.

[0028] In summary, this invention effectively solves the problems of high risk of collapse due to water accumulation in trenches, significant safety hazards and low efficiency in underwater operations, difficulty in ensuring accuracy during long-distance pipeline assembly and hoisting due to soft soil and water accumulation, and high construction costs. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a top view of the track-steel plate foundation of the present invention;

[0031] Figure 2 This is a side view of the three-dimensional mobile work platform of the present invention;

[0032] Figure 3 This is a schematic diagram of the pipeline chute guidance and laying of the present invention.

[0033] In the attached diagram: 1-track, 2-steel plate, 3-laid pipe, 4-pipe chute, 5-assembled truck bed, 6-pipe, 7-gantry crane, 8-trench, 9-tractor. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The present invention will be further explained below with reference to specific embodiments.

[0036] This case involves a municipal long-distance water transmission pipeline project. Its key operating parameters are as follows: total construction length of 800 meters, groundwater level depth of 1.2 meters, geological conditions of silty clay, and pipeline design specifications of DN1200 reinforced concrete pipe (standard length of 6 meters per section).

[0037] Please see Figures 1-3 The present invention provides a method for constructing trench pipelines at high groundwater levels, the method comprising the following steps:

[0038] 1. Pre-construction preparation and trench excavation

[0039] Based on the engineering design drawings and site survey data, a rectangular trench 8 was excavated after precise layout. The trench 8 was designed to have an excavation depth of 3 meters and a width of 2.5 meters. Simultaneously, foundation trenches were excavated at corresponding positions on both sides of the trench 8. The width of the foundation trenches was set at 1 meter to be used for laying the load-bearing foundation for the track 1. After excavation, debris, loose soil, and accumulated water in the foundation trenches were promptly removed. The bottom surface of the foundation trenches was then finely leveled using manual labor and small leveling equipment to ensure that the flatness error of the bottom surface was ≤5mm, meeting the load-bearing requirements of subsequent foundation construction.

[0040] 2. Track-steel plate foundation construction

[0041] After the foundation trench is leveled and accepted, a 16mm thick Q235B steel plate 2 is laid as the load-bearing foundation layer. When laying the steel plate 2, ensure that the joints of adjacent steel plates 2 are tight, and use full welding process to connect the joints, with the weld height controlled at 8mm. On the steel plate 2, position and install the QU70 light rail track 1. The installation direction of the track 1 is parallel to the axis of the trench 8. Use expansion bolts to fix the track 1 to the steel plate 2. The bolt spacing is evenly set to 500mm. After the bolts are tightened, check the parallelism of the track 1 to ensure that the parallelism error of the two rails is ≤3mm and the elevation deviation of the top surface of the track 1 is ≤2mm, so as to ensure the smooth movement of the subsequent work platform.

[0042] 3. Installation and commissioning of the work platform and lifting equipment

[0043] The 50t-class assembly truck bed 5 (designed wheel track 1.8 meters, matching the spacing of QU70 rail 1) was hoisted onto rail 1 using a truck crane. During the hoisting process, the assembly truck bed 5 was kept level to avoid collision with rail 1. After hoisting, the mobility performance of the assembly truck bed 5 was tested by starting the drive system of the assembly truck bed 5 (i.e., the tractor 9) and conducting a back-and-forth movement test to ensure that the assembly truck bed 5 moved flexibly without any jamming, and that the wheels made good contact with rail 1 without any deviation or rail jamming. A 30t-class gantry crane 7 was erected above rail 1. The track of the gantry crane 7 was kept strictly parallel to the pipeline construction track 1 below. The installation position of the gantry crane 7 was precisely positioned and fixed to ensure that the vertical projection range of its lifting hook completely covered the working area of ​​the assembly truck bed 5 and the lifting area of ​​the pipeline 6 above the trench 8. After the lifting equipment was installed, a load test (1.2 times the rated load) was conducted to verify the lifting stability and braking reliability of the equipment.

[0044] 4. Pipeline assembly and laying

[0045] The DN1200 reinforced concrete pipe section is hoisted to the inlet of the pipe chute 4 of the assembly truck bed 5 using a gantry crane 7. During the hoisting process, a special lifting tool (flexible sling) is used to avoid damage to the outer wall of the pipe 6. After the pipe 6 is placed in the pipe chute 4, the laser calibrator mounted on the assembly truck bed 5 is activated to monitor the axial position of the pipe 6 in real time. The posture of the pipe 6 is adjusted by the fine-tuning mechanism of the assembly truck bed 5 to ensure that the pipe 6 to be assembled is precisely aligned with the center line of the interface of the already laid pipe 3, with the axial deviation controlled to ≤1mm. After the interface is aligned, the rubber sealing ring is installed with manual assistance to ensure that the sealing ring is installed in place, without twisting or damage, and that the interface sealing surface is clean and free of debris, thus completing the assembly of the single pipe section 6.

[0046] After assembly, the assembly truck 5 is started and slowly moved along the track 1 to the designated laying position in the trench 8 to avoid the pipe 6 interface being stressed due to inertia. After reaching the position, the hydraulic outriggers of the assembly truck 5 are operated to adjust the height of the assembly truck 5 so that the distance between the outlet end of the pipe chute 4 and the top surface of the pre-set C15 concrete pad in the trench 8 is ≤100mm, ensuring that the pipe 6 slides down smoothly. A buffer device is set at the outlet end of the pipe chute 4, and the pipe 6 is manually and slowly pushed to make the pipe 6 slide into the trench 8 at a uniform speed along the pipe chute 4. During the descent of the pipe 6, a special person is arranged in the trench 8 to guide it and avoid the pipe 6 from colliding with the side wall or pad of the trench 8. After the pipe 6 is in place, the position of the pipe 6 is fixed by the positioning piles pre-set on both sides of the trench 8 to ensure that the axis of the pipe 6 is consistent with the design axis and there is no displacement at the interface.

[0047] Repeat the assembly and laying steps of pipe 6 as described above. After laying 10 consecutive pipe sections 6, use a total station to check and measure the overall axis of the laid pipe 3. Using the design axis as a reference, ensure that the overall axis deviation of the laid pipe 3 is ≤ ±2mm. If the deviation is found to exceed the allowable range, immediately use the fine-tuning mechanism of the assembly truck bed 5 and the positioning piles to correct the deviation until the design requirements are met before continuing the subsequent laying work.

[0048] 5. Subsequent processes

[0049] After all pipelines 6 are laid, the gantry crane 7, the truck bed 5, and the light rail track 1 are dismantled. During the dismantling process, collisions with the laid pipelines 3 should be avoided. After the track 1 and steel plate 2 are removed, the trench 8 is backfilled in layers. The compaction degree is tested to be ≥95%. After backfilling to the design ground elevation, the ground surface is leveled and restored to complete the entire construction process.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing trench pipelines at high groundwater levels, characterized in that, The method includes the following steps: Step 1: Lay steel plates (2) on both sides of the excavated trench (8), and lay tracks (1) parallel on the steel plates (2) to form a track-steel plate foundation; Step 2: Install the assembly truck (5) on the track (1), set up a gantry crane (7) above the track (1), and connect it to the assembly truck (5) through a tractor (9) to build a three-dimensional mobile work platform above the trench (8); Step 3: Install the arc-shaped pipe chute (4) on the assembly truck bed (5), and use the gantry crane (7) to lift the pipe (6) onto the assembly truck bed (5) to complete the assembly of the pipe (6) on the ground. Step 4: Use a tractor (9) to pull the assembly truck (5) to move it above the trench (8), and guide the assembled pipe (6) to slide smoothly into the trench (8) through the pipe chute (4) to connect with the already laid pipe (3) to complete the laying; Step 5: Repeat steps 3 and 4 until the long-distance pipeline (6) is completely laid.

2. The method for constructing trench pipelines at high groundwater levels according to claim 1, characterized in that, In step 1, the steel plate (2) has a thickness of not less than 16mm and is made of Q235B.

3. The method for constructing trench pipelines at high groundwater levels according to claim 1, characterized in that, In step 1, the track (1) is a QU70 light rail, and the track (1) spacing matches the wheel track of the assembled truck bed (5) with an error of ≤5mm.

4. The method for constructing trench pipelines at high groundwater levels according to claim 1, characterized in that, In step 1, the steel plate (2) is laid 1.5 to 2 meters away from the edge of the trench (8), and the coverage of the steel plate (2) is consistent with the pipeline construction length.

5. The method for constructing trench pipelines at high groundwater levels according to claim 1, characterized in that, In step 2, the load capacity of the assembly truck (5) is not less than 50t, and the bottom of the assembly truck (5) is provided with track wheels that are compatible with the track (1).

6. The method for constructing trench pipelines at high groundwater levels according to claim 1, characterized in that, In step 2, the lifting capacity of the gantry crane (7) is not less than 30t, the traveling direction is parallel to the track (1), and the span of the gantry crane (7) covers the trench (8) and the tracks (1) on both sides.

7. The method for constructing trench pipelines at high groundwater levels according to claim 1, characterized in that, In step 3, the curvature of the pipe groove (4) matches the outer diameter of the pipe (6) with an error of ≤3mm, and the inner wall of the pipe groove (4) is provided with a wear-resistant rubber layer.

8. The method for constructing trench pipelines at high groundwater levels according to claim 1, characterized in that, In step 3, the assembly of the pipe (6) on the assembly truck bed (5) includes pipe axis alignment and interface sealing operations.

9. The method for constructing trench pipelines at high groundwater levels according to claim 1, characterized in that, In step 4, after the assembly truck bed (5) is moved above the trench (8), the height is adjusted by hydraulic outriggers so that the distance between the outlet end of the pipe chute (4) and the inner padding layer of the trench (8) is ≤100mm.

10. The method for constructing trench pipelines at high groundwater levels according to claim 1, characterized in that, In step 4, a buffer device is set at the outlet end of the pipe chute (4) during the downward movement of the pipe (6), and the pipe (6) is manually guided to move in the trench (8).

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