Low-disturbance sequential trenching underground continuous wall across underground pipelines and its construction method

Abstract

This invention proposes a low-disturbance, sequential trenching method for constructing a diaphragm wall across underground pipelines. The method includes using a ring-shaped steel plate box to isolate and protect the pipeline, connecting it to a guide wall via embedded parts to avoid excavation disturbance; a rigid waterstop plate and an expansion waterstop strip double structure, along with embedded grouting pipes, are installed at the pipeline-guide wall junction to enhance impermeability; a steel platform is installed above the trench section as a mechanical working surface, with internal steel supports to improve stability; a hydraulic trenching machine and an air-lift reverse circulation drilling rig are used for sequential trenching, with verticality controlled by a side-tooth assembly, and the drill bit direction adjusted using an adjustable truss to overcome the challenge of trenching beneath the pipeline; an innovative trench wall finishing technique is employed, using a serrated scraper to treat convex surfaces and high-pressure grouting to fill concave surfaces. This technology, through multiple protections and low-disturbance processes, effectively ensures pipeline safety, while also featuring high trenching vertical accuracy, excellent water-stopping performance, and high construction efficiency. It significantly improves the construction quality of the diaphragm wall and reduces engineering risks, resulting in significant technical and economic benefits.

Description

Technical Field

[0001] This invention relates to the construction of diaphragm walls, specifically to low-disturbance sequential trenching diaphragm walls spanning underground pipelines and their construction methods. Background Technology

[0002] With the rapid development of underground transportation, diaphragm walls, as an important retaining structure for underground stations, frequently encounter situations where they cross underground pipelines. Because these pipelines belong to different departments, the relocation and coordination procedures are cumbersome, often resulting in delays in pipeline relocation and significantly impacting the normal construction progress of the diaphragm walls. Therefore, protecting underground pipelines is a key aspect of diaphragm wall construction. Simultaneously, the high-frequency vibrations of trenching machinery inevitably disturb the soil in the trenching section, easily causing soil collapse and endangering the safety of construction workers. Therefore, taking appropriate measures to address soil disturbance is also a crucial consideration.

[0003] In summary, in response to technical challenges such as pipeline protection and soil disturbance, there is an urgent need to propose a low-disturbance sequential trenching method for constructing diaphragm walls that cross underground pipelines and its construction. Summary of the Invention

[0004] The purpose of this invention is to provide a low-disturbance sequential trenching diaphragm wall for crossing underground pipelines and its construction method, which can solve technical problems such as pipeline protection and soil disturbance when underground pipelines cross the trench section of the diaphragm wall, and can achieve good technical and economic benefits when applied to actual engineering projects.

[0005] To address the aforementioned technical challenges, this invention provides a method for constructing a low-disturbance, sequentially trenched diaphragm wall spanning underground pipelines, comprising the following steps:

[0006] Step 1: Manually excavate the soil in the area near the underground pipeline;

[0007] Step 2: Install steel plate enclosures with ring clamps to isolate and protect underground pipelines;

[0008] Step 3: Install a steel platform for parking machinery and set up steel supports inside the excavated trench section;

[0009] Step 4: Use a hydraulic trenching machine to excavate the side trenches on both sides of the underground pipeline;

[0010] Step 5: Use an air-lift reverse circulation drilling rig to excavate the trench section directly beneath the underground pipeline;

[0011] Step 6: Break up the sediment at the bottom of the tank with an impact drill and clean the tank walls with a wall brush.

[0012] Step 7: Complete the lowering and translation of the central steel reinforcement cage directly below the underground pipeline;

[0013] Step 8: Hoist the edge reinforcement cage;

[0014] Step 9: Simultaneously pour the diaphragm wall sections symmetrically through the grouting pipe.

[0015] Furthermore, in step two, the end of the ring-shaped steel plate box is connected to the guide walls on both sides through embedded parts; the upper and lower edges of the junction between the underground pipeline and the guide wall are provided with a double water-stop structure consisting of a rigid water-stop plate and an expansion water-stop strip; the expansion water-stop strip is set on the outside of the rigid water-stop plate; a grouting pipe is embedded inside the guide wall, the grouting pipe is located on the side of the underground pipeline and extends to the lower edge of the underground pipeline.

[0016] Furthermore, in step three, the steel platform spans the trench section and extends to the flange of the guide wall; the steel platform is a prefabricated integrated platform, consisting of transverse I-beams, upper steel plates, and lower steel plates; steel bracing is arranged at intervals on the side walls of the guide wall.

[0017] Furthermore, in step four, the hydraulic trenching machine consists of a grab bucket, a first transmission unit, a side gear assembly, a hydraulic system, and a second transmission unit, wherein the side gear assembly for controlling the verticality of the trenching is provided on the outer side of the first transmission unit.

[0018] Furthermore, in step five, the air-lift reverse circulation drilling rig includes a winch, a slider, an articulated truss, a drill bit, and a nozzle tube.

[0019] Furthermore, the slider is controlled by the traction of the wire rope connected to the winch, and slides up and down along the nozzle tube; a hinged truss is fixed on the side of the slider; the hinged truss is an adjustable angle truss; a drill bit is installed on the upper part of the hinged truss.

[0020] Furthermore, in step six, the impact drill consists of a drill rod and an impact drill bit; a thickened steel plate and a serrated plate are added to the lower part of the impact drill bit.

[0021] Furthermore, in step six, the wall brusher includes a wall brusher body, a high-pressure spray pipe, a scraper, a steel brush, and a drive shaft; the wall brusher body is equipped with several high-pressure spray pipes, which are connected to a pumping pipe extending to the mud circulation tank; the wall brusher body is equipped with a steel brush and a serrated scraper on its side.

[0022] Furthermore, in step eight, sandbags are filled between the edge steel reinforcement cage and the trench wall.

[0023] The low-disturbance sequential trenching diaphragm wall spanning underground pipelines is constructed using the aforementioned construction method for low-disturbance sequential trenching diaphragm walls spanning underground pipelines.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) For underground pipelines that cross the trench section, the installation of ring-hooped steel plate boxes for isolation and protection, and the connection and fixation with the guide wall by the embedded parts, avoids the disturbance and damage to the underground pipelines during the later excavation.

[0026] (2) A multi-layer water-stopping technology for the junction of underground pipeline and guide wall was proposed. The upper and lower edges of the junction of underground pipeline and guide wall are equipped with a double water-stopping structure consisting of rigid water-stopping plate and expansion water-stopping strip. Grouting pipes are pre-embedded inside the guide wall for sealing the seepage points, which improves the seepage resistance of the junction of underground pipeline and guide wall.

[0027] (3) A low-disturbance construction technology for diaphragm walls was proposed. A steel platform spanning the trench section was placed on the upper part of the trench section as the working surface for trenching machinery. The inside of the trench section was supported by steel bracing on the side wall of the guide wall, which reduced the disturbance of the trenching machinery to the trench wall and improved the overall stability of the trench section.

[0028] (4) A sequential trenching technology combining hydraulic trenching machine and air-lift reverse circulation drilling machine was proposed. The edge trench section was vertically excavated by hydraulic trenching machine, and the verticality of the trench was controlled by adding a side tooth assembly on the outside of the first transmission part. The middle trench section was horizontally drilled by air-lift reverse circulation drilling machine. An adjustable angle truss was set on the nozzle pipe body. The orientation of the drill bit was changed by adjusting the truss support rod, which solved the problem of trenching the soil under the pipeline.

[0029] (5) A precise repair technology for the trench wall of the diaphragm wall was proposed. For the convex part of the trench wall, the serrated scraper and steel brush on the side of the wall brusher scraped and repaired the excess soil on the trench wall. For the concave part of the trench wall, the wall brusher was connected to the mud circulation pool through the pumping pipe, and the internal high-pressure spray pipe sprayed mud onto the concave part of the trench wall. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of manual excavation in the pipeline area;

[0031] Figure 2 This is a schematic diagram of the isolation and protection provided by the ring-hooped steel plate box;

[0032] Figure 3 This is a schematic diagram of the water-stopping seal at the junction of the pipeline and the diaphragm wall;

[0033] Figure 4 yes Figure 3 Enlarged view of region A in the middle;

[0034] Figure 5 This is a schematic diagram of the guide wall steel bracing reinforcement.

[0035] Figure 6 This is a schematic diagram of the steel platform structure;

[0036] Figure 7 This is a schematic diagram of the troughing process for the left-side section;

[0037] Figure 8 This is a schematic diagram of a hydraulic trenching machine.

[0038] Figure 9 This is a schematic diagram of the right-side trough section.

[0039] Figure 10 This is a schematic diagram of the mid-width trough section.

[0040] Figure 11 This is a schematic diagram of an air-lift reverse circulation drilling rig.

[0041] Figure 12 This is a schematic diagram of impact drilling for crushing sediment;

[0042] Figure 13 This is a schematic diagram of an impact drill structure;

[0043] Figure 14 This is a diagram illustrating the cleaning process of the wall-mounted brush tank.

[0044] Figure 15 This is a schematic diagram of the wall brush device structure;

[0045] Figure 16 This is a schematic diagram of the installation of the medium-width steel reinforcement cage;

[0046] Figure 17 This is a schematic diagram of the installation of the edge reinforcement cage;

[0047] Figure 18 This is a schematic diagram of diaphragm wall grouting;

[0048] Figure 19 This is a schematic diagram of a diaphragm wall.

[0049] In the diagram: 1. Underground pipeline; 2. Ring-hooped steel plate box; 3. Grouting pipe; 4. Embedded parts; 5. Guide wall; 6. Rigid waterstop plate; 7. Expansion waterstop strip; 8. Steel platform; 8.1. Horizontal I-beam; 8.2. Upper steel plate; 8.3. Lower steel plate; 9. Steel bracing; 10. Hydraulic trenching machine; 10.1. Grab bucket; 10.2. First transmission unit; 10.3. Side gear assembly; 10.4. Hydraulic system; 10.5. Second transmission unit; 11. Air-lift reverse circulation drilling rig; 11.1. Winch; 11.2. Sliding block; 11.3 11.1 Hinged truss; 11.4 Drill bit; 11.5 Nozzle pipe; 12. Impact drill; 12.1 Drill rod; 12.2 Impact drill bit; 12.3 Thickened steel plate; 12.4 Serrated plate; 13. Sludge; 14. Wall brush; 14.1 Wall brush body; 14.2 High-pressure spray pipe; 14.3 Scraper; 14.4 Steel brush; 14.5 Drive shaft; 15. Mud circulation tank; 16. Pumping pipe; 17. Middle section reinforcement cage; 18. Edge section reinforcement cage; 19. Sandbag; 20. Grouting conduit; 21. Diaphragm wall section. Detailed Implementation

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0051] Those skilled in the art should understand that, in the disclosure of this application, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on this application.

[0052] Example 1

[0053] like Figures 1-19 As shown, the present invention provides a method for constructing a low-disturbance sequential trench diaphragm wall across underground pipelines, comprising the following construction steps:

[0054] Step 1: Manually excavate the soil in the area near underground pipeline 1;

[0055] In this embodiment, the key operational points are as follows: A manual, layered excavation method is adopted, with the excavation area extending 1.5m to each side of the underground pipeline 1 as the center, and the excavation depth reaching 500mm below the bottom of the pipeline. Tools such as shovels and picks are used during excavation to avoid mechanical vibration causing damage to the pipeline.

[0056] Control parameters: The excavated soil is piled up more than 2m away from the edge of the trench section, and the slope is controlled at 1:0.5 to ensure the stability of the excavation surface.

[0057] Step 2: Install the ring-hooped steel plate box 2 to isolate and protect the underground pipeline 1;

[0058] Specifically, the end of the ring-shaped steel plate box 2 is connected to the two guide walls 5 through the embedded parts 4; the upper and lower edges of the junction between the underground pipeline 1 and the guide wall 5 are provided with a double water-stop structure consisting of a rigid water-stop plate 6 and an expansion water-stop strip 7; the expansion water-stop strip 7 is set on the outside of the rigid water-stop plate 6; a grouting pipe 3 is embedded inside the guide wall 5, the grouting pipe 3 is located on the side of the underground pipeline 1 and extends to the lower edge of the underground pipeline 1.

[0059] In this embodiment, the ring-hooped steel plate box structure is as follows:

[0060] The ring-hooped steel plate box 2 is welded from Q345B steel plate with a thickness of 16mm. The width of the box is 300mm larger than the outer diameter of the underground pipeline 1, and the height covers the pipeline 200mm above and below. L100×10 angle steel embedded parts 4 are welded to both ends of the box. The embedded parts 4 are connected to the C30 reinforced concrete guide walls 5 on both sides by M24 bolts (the cross-sectional dimensions of the guide walls are 1.2m×0.8m).

[0061] Waterstop structure installation:

[0062] At the junction of underground pipeline 1 and guide wall 5, a 10mm thick rigid waterstop 6 (extending 500mm beyond the pipeline on both sides) is installed at the upper and lower edges, and a 20mm×30mm water-swellable waterstop strip 7 (expansion rate ≥250%) is pasted on the outside. A Φ48mm grouting pipe 3 is pre-embedded inside the guide wall 5. The grouting pipe 3 is 150mm from the side of the pipeline, and its bottom end extends 300mm below the lower edge of the pipeline. A grout stop valve is installed at the top of the grouting pipe.

[0063] Step 3: Install the mechanical equipment and moor the steel platform 8 and set up steel supports 9 inside the excavated trench section;

[0064] Specifically, the steel platform 8 spans the channel section and extends to the flange of the guide wall 5; the steel platform 8 is a prefabricated integrated platform, consisting of a transverse I-beam 8.1, an upper steel plate 8.2, and a lower steel plate 8.3; steel bracing 9 is arranged at intervals on the side walls of the guide wall 5.

[0065] In this embodiment, the steel platform structure is as follows:

[0066] Steel platform 8 is a prefabricated integrated structure, spanning the channel section and extending 500mm beyond the flanges of guide wall 5 at both ends. The platform is welded together from transverse I25a I-beams 8.1 (spaced 600mm), a 16mm thick upper steel plate 8.2, and a 10mm thick lower steel plate 8.3, with an overall load-bearing capacity ≥200kN / m. 2 .

[0067] Steel bracing arrangement:

[0068] H200×200 steel bracing 9 is arranged at 2m intervals on the side wall of guide wall 5. The two ends of the steel bracing are fixed to the guide wall through pre-embedded steel plates. The spacing of the bracing is adjusted according to the depth of the trench section (2.5m interval for depth ≤15m, 2m interval for depth >15m).

[0069] Step 4: Use the hydraulic trenching machine 10 to excavate the side trench sections on both sides of the underground pipeline 1;

[0070] Specifically, the hydraulic trenching machine 10 consists of a grab bucket 10.1, a first transmission unit 10.2, a side gear assembly 10.3, a hydraulic system 10.4, and a second transmission unit 10.5, wherein the side gear assembly 10.3 for controlling the verticality of trenching is provided on the outside of the first transmission unit 10.2.

[0071] In this embodiment, the device parameters are:

[0072] The hydraulic trenching machine, model BH12, has a 10.1-ton grab bucket with a capacity of 1.5m³. 3 The first transmission unit 10.2 has a side gear assembly 10.3 (side gear material 42CrMo, tooth pitch 100mm, tooth height 50mm) installed on its outer side. The hydraulic system 10.4 has a working pressure controlled at 20~25MPa and a grooving speed controlled at 1~1.5m / h.

[0073] Verticality control:

[0074] The side tooth assembly 10.3 engages with the soil on the trench wall, and the verticality of the grab bucket is adjusted in real time through the hydraulic system 10.4. During the trenching process, an ultrasonic wall measuring instrument is used to check the verticality every 2m depth, and the verticality deviation is controlled within ≤0.3%.

[0075] Step 5: Use the air-lift reverse circulation drilling rig 11 to excavate the trench section directly below the underground pipeline 1;

[0076] Specifically, the air-lift reverse circulation drilling rig 11 includes a winch 11.1, a slider 11.2, an articulated truss 11.3, a drill bit 11.4, and a nozzle pipe 11.5; wherein, the slider 11.2 is controlled by the traction of the wire rope connected to the winch 11.1 and slides up and down along the pipe body of the nozzle pipe 11.5; the articulated truss 11.3 is fixed to the side of the slider 11.2; the articulated truss 11.3 is an adjustable angle truss; the drill bit 11.4 is installed on the upper part of the articulated truss 11.3.

[0077] In this embodiment, the drilling mechanism structure is as follows:

[0078] The winch 11.1 of the air-lift reverse circulation drilling rig 11 has a traction force ≥50kN, the slider 11.2 slides along the Φ159mm nozzle pipe 11.5 (sliding speed 0.5m / s), the hinged truss 11.3 is an adjustable angle structure (angle adjustment range 0°~30°), and the drill bit 11.4 has a diameter of 800mm and is equipped with alloy cutting teeth at the bottom.

[0079] Trenching operation:

[0080] After the drilling rig is in place, the angle of the hinged truss 11.3 is adjusted by pulling the slider 11.2 with the winch 11.1 so that the drill bit 11.4 is aligned with the soil directly below the pipeline. When trenching, compressed air (pressure 0.6~0.8MPa) is introduced into the nozzle pipe 11.5 to form a reverse circulation for slag removal. The trenching speed is controlled at 0.8~1m / h.

[0081] Step 6: Use the impact drill 12 to break up the sediment 13 at the bottom of the tank, and use the wall brush 14 to clean the tank wall;

[0082] Specifically, the impact drill 12 consists of a drill rod 12.1 and an impact drill bit 12.2; a thickened steel plate 12.3 and a serrated plate 12.4 are added to the lower part of the impact drill bit 12.2;

[0083] The wall scrubber 14 includes a wall scrubber body 14.1, a high-pressure spray pipe 14.2, a scraper 14.3, a steel brush 14.4, and a drive shaft 14.5. The wall scrubber body 14.1 is equipped with several high-pressure spray pipes 14.2, which are connected to a pumping pipe 16 extending to the mud circulation tank 15. The wall scrubber body 14.1 is equipped with a steel brush 14.4 and a serrated scraper 14.3 on its side.

[0084] In this embodiment, the drill rod 12.1 of the impact drill 12 has a diameter of 120mm, and the lower part of the impact drill bit 12.2 is welded with a 20mm thick Q235B thickened steel plate 12.3. A serrated plate 12.4 (serration angle 60°, tooth pitch 30mm) is inlaid at the bottom of the steel plate. The impact frequency is controlled at 40 times / min, crushing the sediment 13 to a particle size ≤50mm.

[0085] Cleaner operation:

[0086] The main body 14.1 of the wall brusher 14 is a steel frame structure, with four Φ32mm high-pressure spray pipes 14.2 (nozzle diameter 5mm, spray pressure 1.5MPa) arranged inside. The spray pipes are connected to the mud circulation tank 15 (mud density 1.15g / cm³) through the pump pipe 16. Steel brushes 14.4 (bristle length 150mm) and serrated scrapers 14.3 (blade thickness 10mm) are installed on the side. The lifting speed is controlled at 0.5m / min during wall brushing, and the wall brushing is repeated 3 to 5 times.

[0087] Step 7: Complete the lowering and translation of the central steel reinforcement cage 17 directly below underground pipeline 1;

[0088] In this embodiment, the parameters of the reinforcing cage are:

[0089] The medium-width steel cage 17 is welded together with Φ22mm main bars (spacing 150mm) and Φ12mm distribution bars (spacing 200mm). The cage length is 500mm shorter than the trench depth and the width is 100mm smaller than the trench width.

[0090] Decentralization process:

[0091] A 25t crawler crane was used for hoisting. The process was paused when the bottom of the steel cage was 200mm from the bottom of the trench. After positioning with a total station, the steel cage was horizontally moved to the design position using hydraulic jacks, with the translation accuracy controlled within ±30mm.

[0092] Step 8: Hoist the edge reinforcement cage 18;

[0093] Specifically, sandbags 19 are filled between the edge steel reinforcement cage 18 and the trench wall.

[0094] In this embodiment, the steel cage is hoisted:

[0095] The edge reinforcement cage (18mm) has the same structure as the middle cage. During hoisting, a four-point hoisting method is used, with the hoisting points set at the top third of the cage. After the reinforcement cage is placed in the trench, its verticality is controlled by a guiding device, with a deviation ≤0.5%.

[0096] Sandbag filling:

[0097] Fill the gap between the edge steel cage 18 and the trench wall with 100mm×200mm sandbags 19. The sandbags are made of woven geotextile and the filling density is ≥85%. Set a layer of sandbags every 2m in height to ensure that the steel cage is positioned stably.

[0098] Step 9: Simultaneously pour the diaphragm wall segment 21 symmetrically through the grouting pipe 20.

[0099] In this embodiment, the casting process is as follows:

[0100] Two Φ250mm grouting pipes are used for symmetrical pouring, with the bottom of the pipes 300~500mm from the bottom of the trench. The concrete strength grade is C35P8, the slump is 180~220mm, the pouring speed is ≥2m / h, and the burial depth of the pipes is controlled at 2~6m during the pouring process until the concrete is poured to 500mm above the design elevation.

[0101] Example 2

[0102] Based on the same concept, this embodiment proposes a low-disturbance sequential trenching underground continuous wall that crosses underground pipelines and is constructed using the construction method of Embodiment 1.

[0103] This embodiment also included an effectiveness verification, as detailed below:

[0104] Pipeline protection effect: During the construction process, the displacement monitoring data of underground pipeline 1 showed that the horizontal displacement was ≤8mm and the vertical displacement was ≤5mm, which met the pipeline protection requirements.

[0105] Water-stopping performance: After the diaphragm wall is constructed, there is no leakage at the joints. According to the on-site water injection test, the water seepage per unit length is ≤0.05L / (m·min).

[0106] Construction efficiency: The construction cycle of a single trench section is shortened by 20% compared with the traditional process, the first-time acceptance rate of trench verticality reaches 98%, and the overall cost is reduced by 15%.

[0107] The parts not described in detail in this application are prior art, and therefore are not described in detail in this application.

[0108] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0109] Although this document uses a significant amount of technical terminology, the possibility of using other terms is not excluded. These terms are used merely to facilitate the description and explanation of the nature of this application; interpreting them as any additional limitation would be contrary to the spirit of this application.

[0110] This application is not limited to the above-described preferred embodiments. Anyone can derive other products in various forms under the guidance of this application. However, regardless of any changes made to their shape or structure, any technical solution that is the same as or similar to that of this application falls within the protection scope of this application.

Claims

1. A construction method for low-disturbance sequential trenching diaphragm walls spanning underground pipelines, characterized in that, Includes the following steps: Step 1: Manually excavate the soil in the vicinity of the underground pipeline (1); Step 2: Install the ring-shaped steel plate box (2) to isolate and protect the underground pipeline (1); the end of the ring-shaped steel plate box (2) is connected to the guide walls (5) on both sides through the embedded parts (4); the upper and lower edges of the underground pipeline (1) and the guide wall (5) are provided with a double water-stop structure consisting of a rigid water-stop plate (6) and an expansion water-stop strip (7); the expansion water-stop strip (7) is set on the outside of the rigid water-stop plate (6); the guide wall (5) is pre-embedded with a grouting pipe (3), which is located on the side of the underground pipeline (1) and extends to the lower edge of the underground pipeline (1); Step 3: Install a steel platform (8) for parking mechanical equipment and set up steel bracing (9) inside the excavated trench section; the steel platform (8) spans the trench section and extends to the flange of the guide wall (5); the steel platform (8) is a prefabricated integrated platform, consisting of transverse I-beams (8.1), upper steel plates (8.2), and lower steel plates (8.3); steel bracing (9) is arranged at intervals on the side wall of the guide wall (5); Step 4: Use a hydraulic trenching machine (10) to excavate the side trenches on both sides of the underground pipeline (1); Step 5: Excavate the trench section directly below the underground pipeline (1) using an air-lift reverse circulation drilling rig (11); the air-lift reverse circulation drilling rig (11) includes a winch (11.1), a slider (11.2), a hinged truss (11.3), a drill bit (11.4), and a nozzle pipe (11.5); the slider (11.2) is controlled by the traction of the wire rope connected to the winch (11.1) and slides up and down along the pipe body of the nozzle pipe (11.5); the hinged truss (11.3) is fixed on the side of the slider (11.2); the hinged truss (11.3) is an adjustable angle truss; the drill bit (11.4) is installed on the upper part of the hinged truss (11.3). Step 6: Break up the sediment (13) at the bottom of the tank with an impact drill (12) and clean the tank wall with a wall brush (14); the wall brush (14) includes a wall brush body (14.1), a high-pressure spray pipe (14.2), a scraper (14.3), a steel brush (14.4) and a drive shaft (14.5); the wall brush body (14.1) is equipped with several high-pressure spray pipes (14.2) inside, and the high-pressure spray pipes (14.2) are connected to a pumping pipe (16) extending to the mud circulation tank (15); the wall brush body (14.1) is equipped with a steel brush (14.4) and a serrated scraper (14.3) on the side; Step 7: Complete the lowering and translation of the central steel reinforcement cage (17) directly below the underground pipeline (1); Step 8: Hoist the edge reinforcement cage (18); Step 9: Simultaneously pour the diaphragm wall section (21) symmetrically through the grouting pipe (20).

2. The construction method for low-disturbance sequential trenching diaphragm wall spanning underground pipelines according to claim 1, characterized in that: In step four, the hydraulic trenching machine (10) consists of a grab bucket (10.1), a first transmission unit (10.2), a side tooth assembly (10.3), a hydraulic system (10.4), and a second transmission unit (10.5), wherein the side tooth assembly (10.3) for controlling the verticality of trenching is provided on the outside of the first transmission unit (10.2).

3. The construction method for low-disturbance sequential trenching diaphragm wall spanning underground pipelines according to claim 1, characterized in that: In step six, the impact drill (12) consists of a drill rod (12.1) and an impact drill bit (12.2); a thickened steel plate (12.3) and a serrated plate (12.4) are added to the lower part of the impact drill bit (12.2).

4. The construction method for a low-disturbance sequential trenching diaphragm wall spanning underground pipelines according to claim 1, characterized in that: In step eight, sandbags (19) are filled between the edge steel reinforcement cage (18) and the trench wall.

5. A low-disturbance, sequentially formed trench diaphragm wall spanning underground pipelines, characterized in that: The diaphragm wall constructed using the low-disturbance sequential trenching method for crossing underground pipelines as described in any one of claims 1-4 is obtained.

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