A method for connecting large-diameter pipelines in small-section tunnels

Abstract

A method for connecting large-diameter pipes in a small-section tunnel. First, arrange multiple piers in the tunnel, and then place the pipes on multiple groups of pipe conveyors and push them into the tunnel with a forklift. When pushed to the piers, use a jack to lift the pipes, place the pipe conveyor or hydraulic jack conveyor at the other end of the pier, and then the forklift pushes the pipe forward until the pipe finally lands on the pipe conveyor or hydraulic jack conveyor. Subsequently, continue to push the pipe forward with the forklift. After passing over multiple piers, it is done. Finally, use a jack, a gantry, and a chain block to adjust the pipe and connect and weld it to the adjacent pipes. The method for connecting large-diameter pipes in a small-section tunnel provided by the present invention is safe, efficient, and has a relatively low construction cost.

Description

Technical Field

[0001] The invention relates to a connecting method, in particular to a connecting method for a large-diameter pipeline in a small-section tunnel. Background Art

[0002] In recent years, with the continuous advancement of urbanization, the development and utilization of water resources have received more and more attention, and there are more and more infrastructure projects involving urban water supply and drainage pipelines. When installing pipelines on land, when there are obstacles such as mountains in the pipeline laying area, tunnels are usually excavated, and then the pipelines are placed in the tunnel for laying. However, the tunnel for placing the pipeline excavation should not be too large. Too large will lead to an increase in construction costs. When installing pipelines in small-section tunnels, due to the small diameter of the small-section tunnel, such as the tunnel in this application is a city gate tunnel type with a size of 2.7m*2.7m, and the diameter of the pipeline installed in the tunnel is 1.020m. Conventional lifting and hoisting equipment is difficult to enter the tunnel, and the working space in the tunnel is also small (the pipeline is placed in the center of the tunnel, and the width between the outer wall of the pipeline and the left and right side walls is 1m each). In addition, the first end of the pipeline needs to pass over multiple piers and finally place the pipeline on these piers for installation. Due to the height and width restrictions of the tunnel, how to efficiently, conveniently and safely install large-diameter pipelines in small-section tunnels has certain technical difficulties.

[0003] The patent "A method for quick installation of large-diameter pipelines in small-section tunnels" with application number "202211503487.6" states in comparative document 1 that during the takeover process, the transportation operation is mainly carried out by the transport vehicle and the transport tractor head. When the tractor head is transported to the appropriate position, it needs to drive out, which requires the dimensions of both sides of the pipeline to be larger to ensure that the tractor at the front can drive out from one side of the pipeline. However, the pipeline of this patent needs to be installed in the center of the tunnel, and the space on both sides of the pipeline is less than 1m. The working space cannot realize the tractor of comparative document 1 to return to the original route later and dock the next section of the pipeline.

[0004] The patent application number is "202021742232.1", "A conveying device for pipes in small-section tunnels". This device requires the installation of tracks in the tunnel in advance, and then relies on a transport cart to transport the pipes on the tracks. Due to the need to install tracks and the need to dismantle the pipes after installation, the construction cost is significantly increased. The conveying device of this patent does not require the installation of tracks, and relies on a forklift to push the pipes placed on the pulley transport cart forward. The construction cost is low and the construction is more flexible and convenient.

[0005] The patent "A Pipe Installation and Transportation Device for Small Cross-Section Tunnels" with the application number "202322250385.4". From the perspective of the local structure, when the gantry is smaller than the cross-section of the tunnel and the pipe diameter is not large, it can be applied to this patent application. However, due to the presence of the gantry and multiple connecting rods in this patent, a certain working space on the left and right of the tunnel is occupied. Therefore, during the jacking process of the pipe, the axis of the pipe needs to be precisely controlled. If there is a slight deviation, it will collide with the tunnel wall, and the overall operation difficulty is relatively large. At the same time, this patent only provides a pipe transportation device, and it is impossible to see how to control the direction of the pipe at the front end during the forward jacking process of the pipe in this patent. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for connecting large-diameter pipes in small cross-section tunnels, which is safe, efficient, and has a relatively low construction cost.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for connecting large-diameter pipes in small cross-section tunnels, comprising the following steps:

[0009] Step 1: Before transporting and installing the pipes into the tunnel, place multiple prefabricated piers at the designated positions for pipe installation in the tunnel; ensure that the multiple piers are on the designed route and in a straight line;

[0010] Step 2: Arrange multiple groups of pipe transport vehicles at a certain interval in advance at the tunnel entrance, and place the pipes on the multiple groups of pipe transport vehicles through a crane;

[0011] Step 3: Slowly jack the pipe forward at the end of the pipe by a forklift, and manually control the forward direction of the pipe at the front end of the pipe to make the pipe jack forward along the established pipeline;

[0012] Step 4: When the pipe is jacked to about 5 - 10 meters near the pipe installation position, at this time, the forklift stops jacking the pipe forward; the jack jacks up the front end of the pipe, removes the pipe transport vehicle at the very front of the pipe, and replaces it with a hydraulic jack transport vehicle;

[0013] Step 5: Slowly jack forward again by the forklift. When the pipe is jacked near the first pier, stop jacking; jack up the front end of the pipe again by the jack, take out the hydraulic jack transport vehicle after removing it, and place the hydraulic jack transport vehicle at the other end of the first pier; then continue to slowly jack the pipe forward by the forklift. When the pipe crosses the first pier, promptly catch it with the hydraulic jack transport vehicle;

[0014] Step 6: After adjusting the pipeline to a suitable height again through the hydraulic jack conveyor truck, continue to push it forward with a forklift; when the first group of pipeline conveyor trucks in the middle of the pipeline are pushed to near the first pier, it is difficult for the first group of pipeline conveyor trucks in the middle of the pipeline to cross the first pier due to the existence of the first pier; jack up the pipeline again, remove the first group of pipeline conveyor trucks, and place the first group of pipeline conveyor trucks near the other end of the first pier, waiting for the pipeline to be pushed over the first pier, and the first group of pipeline conveyor trucks continue to support the pipeline to move forward;

[0015] Step 7: During the subsequent operation process, when the hydraulic jack conveyor truck or the pipeline conveyor truck touches the corresponding pier, repeat the operations in Steps 5 to 6 above until it is pushed to the designated area for pipeline installation;

[0016] Step 8: When the pipeline is pushed to near the pipeline docking by a forklift, withdraw the forklift, and finely adjust the horizontal distance between the interfaces of the pipelines by setting a jack at the end of the pipeline to make the horizontal distance between the pipelines at the best welding distance. The vertical distance of the pipeline is adjusted by setting gantries and hanging chains on both sides of the pipeline. When the adjustment is in place, fix the adjacent two pipelines with hoop and weld the pipelines for fixation;

[0017] Step 9: After the pipeline installation is completed, conduct a hydrostatic test on the installed pipeline according to the construction specifications and design requirements. After the hydrostatic test is qualified, make a concrete pier, transport the concrete to the outlet by a trolley, and pour the concrete pier.

[0018] The pipeline conveyor truck includes a vehicle frame. Universal wheels are provided at the front end of the bottom of the vehicle frame, and fixed pulleys are installed at the rear end. Grooves are respectively fixed on both sides of the front and rear of the top end of the vehicle frame. Wedges are placed in the grooves to limit and support the pipeline; connecting rings are fixed on both sides between the front and rear grooves.

[0019] A direction control rod is fixed on the wheel frame of the universal wheel of the pipeline conveyor truck at the head end of the pipeline.

[0020] The pier includes a pier main body. The lower end of the pier main body is fixed in the groove of the foundation surface through legs. A groove is provided in the upper part of the pier main body, and sand is filled in the groove; arc surfaces are provided at the front and rear of the upper end of the pier main body to support and limit the pipeline, and lifting rings are provided on the left and right of the upper end of the pier main body.

[0021] Detachable rollers are provided at the arc surface near one side of the upper end of the pier main body, and the rollers are arranged at intervals in pairs; columns in pairs are fixed on the left and right at the upper end of the pier main body, and the interval between the columns in pairs matches the diameter of the shaft rods at both ends of the rollers, and the shaft rods are placed between the corresponding columns in pairs.

[0022] The upper end of the pipeline conveyor truck is 50 mm higher than the upper end of the pier main body.

[0023] The present invention provides a method for connecting large-diameter pipelines in small-section tunnels, which has the following technical effects:

[0024] 1). By installing a set of fixed pulleys at the rear end of the vehicle frame and a set of universal wheels at the front end of the vehicle frame, and connecting the wheel frame of the universal wheels with a direction control rod. During the pipeline walking and transportation process, when relying on a forklift to push the pipeline forward from behind, the direction of the universal wheels is controlled by manually controlling the direction control rod at the front end, thereby controlling the transportation direction of the pipeline, and realizing flexible deviation correction and adjustment of the pipeline in the small-section tunnel. By leaving four notches for placing wooden wedges on the upper part of the vehicle frame, before hoisting the pipeline onto the vehicle frame, placing triangular wooden wedges in the notches can increase the stability of the pipeline. The wooden wedges can prevent the vehicle frame from colliding and damaging the pipeline surface. At the same time, a set of lifting rings is reserved on the upper part of the vehicle frame, which provides stability during the pipeline transportation process by tying and fixing the pipeline and the trolley with ropes.

[0025] 2). By placing the legs of the pier main body in the grooves on the foundation surface and filling with mortar, the stability of the pier main body can be increased. By filling medium-coarse sand in the grooves of the pier main body, protection can be formed for the pipeline; by setting the contact surface between the pipeline and the pier main body as an arc surface, the pier main body can be closely attached to the pipeline, improving the stability of the pipeline. By installing paired sliding rollers at the top of the pier main body, the shaft rods at both ends of each sliding roller are limited by columns front and back. In this way, when the pipeline falls on the pier main body, the pipeline is supported by the sliding rollers, which is convenient for moving forward and backward for fine adjustment; after adjustment and positioning, the pipeline is lifted by a jack, and the pulley can be directly taken out, which is simple and convenient, ensuring the stability of the pipeline in the later stage.

[0026] 3). The pipeline installation method provided by this patent installs the pipeline through the cooperation of machinery and manual labor. At the rear end, a forklift is used to push the pipeline placed on the pipeline transporter, and at the front end, manual labor is relied on to adjust and control the forward direction of the pipeline transporter. When pushing to near the pipeline interface, by using tools such as jacks and lifting chains, precise docking of the pipeline is achieved. This method is applicable to pipeline installation construction with small working surfaces (≤1m) on both sides of the small-section tunnel. After the pipeline docking is completed, the trolley can be taken out from the working surfaces on both sides of the pipeline, which has the advantages of low construction cost, simple process, and convenient operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The following further describes the present invention in conjunction with the drawings and embodiments:

[0028] Figure 1 It is a structural schematic diagram of the pipeline transporter in the present invention (the first pipeline transporter).

[0029] Figure 2 It is a structural schematic diagram of the notch of the pipeline transporter in the present invention.

[0030] Figure 3 It is a schematic structural diagram of the pipeline transporter in the present invention (the second pipeline transporter).

[0031] Figure 4 It is a schematic diagram of the cooperation between the first pipeline transporter and the pipeline in the present invention.

[0032] Figure 5 It is a schematic diagram of the working state of the pipeline transporter in the present invention (a, b, and c respectively represent three groups of pipeline transporters).

[0033] Figure 6 It is a schematic structural diagram of the abutment in the present invention (the first perspective).

[0034] Figure 7 It is a top view of the abutment in the present invention.

[0035] Figure 8 It is a schematic structural diagram of the abutment in the present invention (the second perspective).

[0036] Figure 9 It is a schematic diagram of the state where the pipeline is transported to the tunnel entrance in the present invention.

[0037] Figure 10 For Figure 9 left view.

[0038] Figure 11 It is a schematic diagram of the state where the pipeline is transported to near the pipeline installation position in the present invention (a, b, and c respectively represent three groups of pipeline transporters, d, e, and f respectively represent three abutments, and g represents the hydraulic jack transporter).

[0039] Figure 12 It is a schematic diagram of the state change of the hydraulic jack transporter crossing the first abutment in the present invention.

[0040] Figure 13 It is a schematic diagram of the state change of the second pipeline transporter crossing the first abutment in the present invention.

[0041] Figure 14 It is a schematic structural diagram of the hydraulic jack transporter in the present invention.

[0042] In the figure: pipeline transporter 1, forklift 2, abutment 3, pipeline 4, tunnel 5, jack 6, hydraulic jack transporter 7, vehicle frame 1.1, universal wheel 1.2, direction control lever 1.3, fixed pulley 1.4, notch 1.5, connecting ring 1.6, side plate 1.5.1, back plate 1.5.2, bottom plate 1.5.3. Detailed implementation manners

[0043] The pipeline in this embodiment is a steel pipeline with a diameter of 1.02 m. The 12 m pipeline is pre-assembled outside the tunnel and extended to 24 m.

[0044] The present invention is equipped with a pipeline conveying vehicle 1 for conveying pipelines in the early stage, a forklift 2, and a supporting pier 3 for fixing and installing pipelines in the later stage.

[0045] like Figures 1-4 As shown, the pipeline transport vehicle 1 includes a frame 1.1, which is welded into a frame structure using angle steels. A universal wheel 1.2 is provided at one end of the bottom of the frame 1.1, and a fixed pulley 1.4 is installed at the other end of the frame 1.1. The fixed pulley 1.4 and the universal wheel 1.2 together form a pulley to facilitate the movement of the frame 1.1.

[0046] The top of the frame 1.1 is fixed with notches 1.5 on both sides, which are arranged symmetrically. Wooden wedges 1.7 are placed in the notches 1.5. The wooden wedges are triangular columns, which can limit the position of the pipes to prevent them from rolling and falling, and ensure stability. Connecting rings 1.6 are fixed on both sides between the front and rear notches 1.5. The connecting rope passes through the connecting rings 1.6 to tie the pipes to the frame 1.1.

[0047] Each slot 1.5 includes left and right side panels 1.5.1, the side panels 1.5.1 are arranged at intervals, the outer sides of the side panels 1.5.1 are connected to the back panel 1.5.2, and the bottom ends of the side panels 1.5.1 are connected to the bottom panel 1.5.3. The side panels 1.5.1 are triangular plates, and the slot formed is a triangular prism. The wooden wedge 1.7 is a triangular prism matching with the notch. The triangular prism structure can limit the pipe, and the wooden wedge itself can also avoid collision with the pipe to scratch and damage.

[0048] In addition, a direction control lever 1.3 is fixed on the wheel frame of the universal wheel 1.2 of the pipeline conveying vehicle 1 located at the front end of the pipeline. The direction control lever 1.3 is used to manually adjust and control the direction of the universal wheel 1.2 to facilitate deviation correction.

[0049] like Figure 14 As shown, the pipe conveying vehicle 1 located at the front end of the pipe can be replaced with a hydraulic jack conveying vehicle 7 at a later stage. The lower part of the hydraulic jack conveying vehicle 7 is a manual hydraulic forklift. A frame 1.1 is fixed on the plate of the manual hydraulic forklift. The frame 1.1 is also fixed with a notch 1.5 and a connecting ring 1.6. The function is the same as that of the pipe conveying vehicle 1. Both can transport the pipe and can be lifted and lowered, thereby improving flexibility.

[0050] like Figures 6-8As shown in the figure, the pier 3 includes a pier main body 3.1, and the height of the pier main body is about 60 cm. The pier main body 3.1 is of a square structure and includes a bottom plate 3.1.1 and side plates 3.1.2 around it. Four legs 3.2 are reserved at the bottom of the pier main body 3.1. After the pier main body 3.1 is transported to the designated position, the four legs 3.2 are embedded into the grooves reserved on the foundation surface, and mortar is filled to further increase the stability of the pier main body 3.1. Medium and coarse sand is filled in the grooves on the upper part of the pier main body 3.1, which can protect the overall structure of the pipeline when the pipeline is placed. In addition, arc surfaces 3.4 are provided on the front and rear side plates 3.1.2 of the pier main body 3.1, which can increase the close-fitting degree between the pipeline and the pier 3 and improve the stability of the pipeline. Hoisting rings 3.5 are fixed on the left and right side plates 3.1.2 of the pier main body 3.1, which is convenient for the hoisting and transportation of the pier 3 in the early stage and convenient for fixing the pipeline in the later stage. After the pipeline is placed in place, the pipeline is tied with ropes, and both ends are connected and fixed to the hoisting rings 3.5 to further increase the stability of the pipeline and the pier 3.

[0051] In addition, a set of sliding rollers 3.6 that are convenient for installation and disassembly are provided at the arc surface 3.4 near one side of the top of the pier main body 3.1. When the pipeline is transported to the pier main body 3.1, due to the small cross-section of the pipeline, it is difficult for conventional hoisting machinery to adjust the pipeline again. By installing a set of sliding rollers 3.6 on each support, placing the pipeline on the sliding rollers 3.6, and slowly providing a top thrust by the forklift at the tail, the pipeline can be transported to the designated position. After the whole pipeline is moved to the appropriate position, the sliding rollers 3.6 on the support are taken out after the pipeline is lifted by a jack and a gantry or other means.

[0052] Here, in order to facilitate removal, two pairs of columns 3.6.1 are fixed on both the left and right sides of the top of the pier main body 3.1. The interval between the paired columns 3.6.1 matches the diameter of the shaft rods 3.6.2 at both ends of the sliding roller 3.6. The paired columns 3.6.1 can play a role in limiting the shaft rods 3.6.2, which is convenient for the support and rolling of the pipeline in the early stage; at the same time, it is convenient to directly remove it in the later stage, which is simple and efficient.

[0053] A method for connecting large-diameter pipelines in a small-section tunnel includes the following steps:

[0054] Step 1: Before transporting and installing the pipeline 4 into the tunnel, place multiple prefabricated piers 3 (cement concrete) at the designated positions for pipeline installation; after measuring and determining the plane position and elevation of the piers 3, adjust the placement using a forklift 2 according to the points of construction layout, ensuring that the piers 3 are on the designed route and in a straight line.

[0055] In this embodiment, since the length of the pipeline 4 installed each time is 24 meters, 3 piers 3 are arranged each time ( Figure 11They are represented by d, e, and f respectively in the figure. The distance between adjacent piers 3 is 10 meters, and the height of the pier main body 3.1 is 50 mm lower than that of the pipeline transporter 1.

[0056] The height of the pier main body 3.1 plus the height of the sliding roller (with a diameter of 100 mm) is basically the same as the height of the pipeline transporter. After the pipeline is sent to the designated position by relying on the sliding roller and the pipeline transporter, the pipeline is jacked up by relying on a jack, and the sliding roller is taken out, so that the pipeline falls onto the arc surface of the pier.

[0057] The precast pier is fixed by filling cement mortar at the contact surface between the pier 3 and the tunnel foundation, and medium-coarse sand is filled in the upper groove of the pier. An arc surface is provided on the upper part of the pier 3, so that the pipeline 4 can be in perfect contact with the medium-fine sand of the pier 3 after installation.

[0058] Step two: As Figures 9-10 shown in the figure, multiple groups of pipeline transporters 1 are pre-arranged at the tunnel entrance at a distance of 8 meters. The pipeline 4 is placed on multiple groups of pipeline transporters 1 by a crane. Flexible material wooden wedges are placed at the part where the upper part of the pipeline transporter 1 contacts the pipeline 4 to avoid damage to the pipeline 4 caused by impact.

[0059] Here, the pipeline transporter 1 is 50 mm higher than the pier 3 and is divided into two types. The first pipeline transporter with a controllable direction at the front end of the pipeline (a total of one group, Figure 11 represented by a) and the second pipeline transporter in the middle of the pipeline (a total of two groups, Figure 11 represented by b and c). The pulleys of the first pipeline transporter are a combination of universal wheels and directional wheels. One group connected to the direction control rod 1.3 is a universal wheel (front end), and the direction of the pipeline can be adjusted by manually adjusting the direction control rod 1.3; the other group is a set of directional pulleys (rear end). The second pipeline transporter is also a combination of directional wheels and universal wheels. The front group is a set of directional wheels, and the rear group is a set of universal wheels. In this way, when the pipeline is pushed forward, on the one hand, the pipeline can be finely adjusted. On the other hand, the combination of fixed pulleys and universal wheels can prevent the pipeline from deviating greatly.

[0060] The reason why the front group of the second pipeline transporter is a set of directional wheels and the rear group is a set of universal wheels: The direction of the pipeline is mainly adjusted by the direction control rod 1.3 at the very front end. Therefore, the front end is also the primary end for controlling the direction. At the same time, it is also necessary to prevent the front end direction from deviating too much during the adjustment process. Therefore, the front end of the second pipeline transporter is a set of directional wheels, and the rear end is a set of universal wheels. If the front end of the second pipeline transporter is a set of universal wheels and the rear end is a set of directional wheels, although it will make it easier to adjust the direction of the pipeline, it also increases the insecurity of the pipeline, making it more likely to deviate, and the difficulty of manually controlling the direction of the pipeline also increases.

[0061] The pipeline transporter 1 in the present invention has undergone multiple demonstration tests. By combining fixed pulleys and universal wheels and reasonably setting the directions of the front and rear wheels of the first pipeline transporter and the second pipeline transporter, relatively stable jacking transportation of the pipeline can be achieved. If only fixed pulleys are used, it is difficult to correct the deviation of the pipeline. If all universal wheels are used, due to the large self-weight of the pipeline, the stability control of the pipeline is poor. By adopting the combined layout form, the stability of the pipeline during the jacking process can be better achieved.

[0062] Step three: As Figure 9 shown, the end of the pipeline is slowly jacked forward by the forklift 2 against the pipeline 4. The part of the forklift 2 in direct contact with the pipeline 4 is made of flexible materials such as rubber or wood. The front end (front) of the pipeline 4 controls the advancing direction of the pipeline 4 by manually controlling the direction control rod 1.3, so that it is jacked forward along the established pipeline.

[0063] Step four: As Figure 11 shown, when the pipeline 4 is jacked to about 5 - 10 meters near the pipeline installation position (close to the first pier 3, and the first pier 3 is represented by d), the pipeline 4 stops jacking forward. The jack 6 is used to lift the front end of the pipeline, the first pipeline transporter (represented by a) is removed, and a hydraulic jack transporter 7 (represented by g) is installed. The height of the hydraulic jack transporter 7 adjusts the height of the pipeline 4 to a proper height 50 mm higher than the pier. The function of being 50 mm higher than the pier: At this time, the concrete pier has been fixed in place. Due to the large self-weight of the pipeline and the slightly poor flatness of the foundation, it can prevent the pipeline from colliding with the pier during the jacking process, causing damage to the pier and the external anti-corrosion of the pipeline. After passing over the first pier, it is then placed on the sliding roller 3.6 of the pier. The general principle is that each time the pipeline opening passes over a pier, it needs to be lifted, and then placed on the pier after passing over, relying on the sliding roller 3.6 of the pier for support.

[0064] The reason for not directly using the first pipeline transporter to support until close to the first pier 3 and then using the jack to remove it and place the hydraulic jack transporter on the other side is as follows: Due to the relatively long length of the front direction control rod of the first pipeline transporter, two people are required to operate and control it at the same time. At this time, if it continues to be used, the operation space will be limited and it will be difficult to continue jacking forward. Therefore, it is more convenient to install the hydraulic jack transporter in a small space and only one person is needed for operation.

[0065] By replacing the first pipeline transporter with the hydraulic jack transporter 7, it is convenient to accurately adjust the installation height of the pipeline 4, control the distance between the pipeline 4 and the pier 3, and facilitate the installation of the pipeline 4 in a small-section tunnel.

[0066] Step five: As Figure 12As shown in the figure, slowly push forward again by the forklift 2. When pushing the pipeline 4 to near the abutment 3(d), stop pushing; lift the front end of the pipeline 4 by the jack 6 again. After lowering the height of the hydraulic jack transporter 7 and taking it out, place it at the other end of the abutment 3(d); when the hydraulic jack transporter 7 is taken out and placed at the other end of the abutment 3(d), continue to slowly push the pipeline 4 forward by the forklift 2. When the pipeline 4 crosses the abutment 3(d), promptly catch it with the hydraulic jack transporter 7.

[0067] Step Six: As Figure 13 shown in the figure, adjust the pipeline 4 to a suitable height again (adjust here by the hydraulic jack transporter 7. When near the abutment, the advancing end of the pipeline has always relied on the hydraulic jack trolley for height adjustment. Generally speaking, only when about to cross the abutment, it is 50 cm higher than the abutment. After crossing, lower the height. At this time, the pipeline is transported by the sliding rollers 3.6 on the abutment. This is mainly because the sliding rollers 3.6 on the concrete abutment have better bearing capacity. If it has been 50 cm higher all the time, the self-weight of the pipeline is relatively large, and all the gravity is borne by the vehicle frame, which is likely to reduce the service life of the vehicle frame). Then, continue to push forward by the forklift 2; when a set of second pipeline transporters (b) in the middle of the pipeline is pushed to near the abutment 3(d), it is difficult for the second pipeline transporter (b) to cross the abutment 3(d) due to the existence of the abutment 3(d)); lift the pipeline 4 by the jack 6 again. After taking out the second pipeline transporter (b), place it near the other side of the abutment 3(d), and wait for the pipeline to be pushed across the abutment 3(d) and continue to support the pipeline to move forward.

[0068] When taking out the second pipeline transporter (b) here, during actual construction, if it can be taken out only by relying on the jack to lift the pipeline, that is the best. If it is difficult to take out, the hydraulic jack transporter 7 needs to be used to lift the pipeline together.

[0069] During the process of the pipeline being pushed across the abutment 3 by the jack 6, the function of the jack 6 is only to lift the pipeline and then take out the pipeline transporter from under the pipeline. Otherwise, due to the existence of the abutment, it will hinder the advancement of the pipeline transporter. After taking out the transporter, lower the jack. At the end of the pipeline, at this time the forklift still exists, and the pushing force is provided by the forklift, and slowly push the pipeline forward.

[0070] After the second pipeline transporter moves from one side of the abutment 3 to the other side, to ensure construction safety, it is necessary to tie the pipeline tightly again to prevent the pipeline from shifting.

[0071] Step Seven: During the subsequent operation process, when the hydraulic jack transporter 7 or the second pipeline transporter touches the corresponding abutment 3, repeat the above operations until it is pushed to the designated area for pipeline installation.

[0072] Step 8: When the pipeline is transported to about 1 m near the interface with the previous section of the pipeline, the operating space of the hydraulic jack conveyor vehicle is limited at this time, and the hydraulic jack conveyor vehicle is withdrawn. Rely on the forklift at the end to slowly push the pipeline forward again. When the distance from the interface with the previous section is about 0.2 - 0.4 m, stop pushing, withdraw the forklift, and the subsequent pushing is replaced by the jack to finely adjust and push the pipeline forward. By setting a jack 6 at the end of the pipeline, the horizontal distance between the interfaces of the pipeline is finely adjusted to make the horizontal distance between the pipelines at the best welding distance. The vertical distance of the pipeline is adjusted by setting simple U-shaped gantry frames and chain hoists on both sides of the pipeline. After the adjustment is in place, fix the adjacent two pipelines with hoop clamps and weld the pipelines for fixation.

[0073] After the pipeline welding is completed, internal anti-corrosion treatment is carried out on the pipeline. The anti-corrosion coating is epoxy powder, and manual coating can be used for larger pipe diameters. Before coating, the inner wall surface of the steel pipe is treated, and garbage, floating dust, and floating rust are removed. First, apply the primer pre-coating. After the primer is cured, apply the second primer. After the second primer is cured, apply the third primer, with an interval of more than 4 hours in between. Then, observe and repair the missed points, and make up the coating layer by layer according to the construction steps. After the internal anti-corrosion of the entire section of the pipeline is completed, pressure testing should be carried out in a timely manner. The open ends of the pressure-tested pipeline should be blocked with blind plates in advance and temporary supports should be added. Gate valves cannot be used instead. The fixed piers at places such as the pipeline should reach the design strength during the test. When there is pressure in the pipeline, it is strictly prohibited to repair pipeline defects, and the pipeline cannot be inspected by hammering the pipe wall and the interface with a hammer. Before the pressure test, the air in the pipeline is exhausted first, and the pipeline is filled with clear water for infiltration. The pipeline is infiltrated for 24 h. The length of the pressure-tested pipe section is 1 km, the designed working pressure of the pipeline is 0.6 MPa, and the test pressure is 1.1 MPa.

[0074] Step 9: After the pipeline installation is completed, conduct a water pressure test on the installed pipeline in accordance with the construction specifications and design requirements. After the water pressure test is qualified, make concrete anchor blocks, transport the concrete to the outlet by trolley, and pour the concrete anchor blocks.

Claims

1. A method for connecting a large-diameter pipeline in a small-section tunnel, comprising the following steps: Step 1: Before the pipeline (4) is transported and installed in the tunnel, a plurality of prefabricated piers (3) are placed at designated locations for pipeline installation in the tunnel; ensuring that the plurality of piers (3) are on the designed route and in a straight line; Step 2: Arrange multiple groups of pipeline transport vehicles (1) at a certain interval in advance and place them at the tunnel entrance, and place the pipeline (4) on the multiple groups of pipeline transport vehicles (1) by means of a crane; Step 3: The end of the pipeline is slowly pushed forward by a forklift (2), and the head end of the pipeline (4) is manually controlled to control the forward direction of the pipeline (4), so that the pipeline (4) is pushed forward according to the predetermined pipeline route; Step 4: When the pipeline (4) is pushed to about 5 to 10 meters near the pipeline installation position, the forklift (2) stops pushing the pipeline (4) forward; the jack (6) lifts the front end of the pipeline (4), withdraws the pipeline conveying vehicle (1) at the front end of the pipeline (4), and replaces it with a hydraulic jack conveying vehicle (7); Step 5: Push the pipe (4) forward slowly again by the forklift (2). When the pipe (4) is pushed to the vicinity of the first pier (3), stop pushing. Lift the front end of the pipe (4) by the jack (6) again, take out the hydraulic jack transport vehicle (7), and place the hydraulic jack transport vehicle (7) at the other end of the first pier (3). Continue to push the pipe (4) forward slowly by the forklift (2). When the pipe (4) passes over the first pier (3), catch it in time with the hydraulic jack transport vehicle (7). Step 6: After adjusting the pipeline (4) to a suitable height again by means of the hydraulic jack conveyor (7), the forklift (2) continues to push forward; when the first group of pipeline conveyor vehicles (1) in the middle of the pipeline is pushed to the vicinity of the first pier (3), the first group of pipeline conveyor vehicles (1) in the middle of the pipeline is difficult to pass over the first pier (3) due to the existence of the first pier (3); the pipeline (4) is lifted up again by means of the jack (6), and after taking out the first group of pipeline conveyor vehicles (1), the first group of pipeline conveyor vehicles (1) are placed near the other end of the first pier (3), and the pipeline is pushed over the first pier (3), and the first group of pipeline conveyor vehicles (1) continue to support the pipeline to move forward; Step 7: During the subsequent operation, when the hydraulic jack conveyor vehicle (7) or the pipeline conveyor vehicle (1) hits the corresponding pier (3), the operations of steps 5 to 6 are repeated until the pipeline is pushed to the designated area for installation; Step 8: When the pipeline is pushed by the forklift (2) to the vicinity of the pipeline joint, the forklift (2) is withdrawn, and the horizontal distance of the pipeline interface is finely adjusted by setting a jack (6) at the end of the pipeline so that the horizontal distance between the pipelines is at the optimal welding distance. The vertical distance of the pipeline is adjusted by setting a door frame and a lifting chain on both sides of the pipeline. When the adjustment is in place, the two adjacent pipelines are fixed by a clamp and the pipeline is fixed by welding; Step 9: After the pipeline (4) is installed, a water pressure test is performed on the installed pipeline according to the construction specifications and design requirements. After the water pressure test is passed, a concrete anchor pier is made, and the concrete is transported to the outlet by a trolley to cast the concrete anchor pier.

2. A method for connecting a large-diameter pipeline in a small-section tunnel according to claim 1, characterized in that: The pipeline transport vehicle (1) comprises a vehicle frame (1.1), a universal wheel (1.2) being provided at the front end of the bottom of the vehicle frame (1.1), and a fixed pulley (1.4) being installed at the rear end; notches (1.5) are respectively fixed on both sides of the front and rear ends of the top of the vehicle frame (1.1), wooden wedges (1.7) are placed in the notches (1.5), and the wooden wedges (1.7) provide position-limiting support for the pipeline; and connecting rings (1.6) are fixed on both sides between the front and rear notches (1.5).

3. A method for connecting a large-diameter pipeline in a small-section tunnel according to claim 2, characterized in that: A direction control rod (1.3) is fixed on the wheel frame of the universal wheel (1.2) of the pipeline transport vehicle (1) at the head end of the pipeline (4).

4. A method for connecting a large diameter pipeline in a small cross-section tunnel according to claim 1, characterized in that: The pier (3) comprises a pier body (3.1), the lower end of the pier body (3.1) is fixed in a groove on a foundation surface via legs (3.2), a groove (3.3) is provided on the upper part of the pier body (3.1), and the groove (3.3) is filled with sand; arcuate surfaces (3.4) are provided at the front and rear ends of the upper end of the pier body (3.1), the arcuate surfaces (3.4) support and limit the position of the pipeline, and lifting rings (3.5) are provided on the left and right ends of the upper end of the pier body (3.1).

5. A method for connecting a large-diameter pipeline in a small-section tunnel according to claim 4, characterized in that: A detachable sliding roller (3.6) is provided at the arc surface (3.4) on one side of the upper end of the pier body (3.1), and the sliding rollers (3.6) are arranged in pairs at intervals; pairs of columns (3.6.1) are fixed on the upper end of the pier body (3.1) on the left and right sides of the sliding rollers (3.6), and the interval between the pairs of columns (3.6.1) matches the diameter of the shaft rods (3.6.2) at both ends of the sliding rollers (3.6), and the shaft rods (3.6.2) are placed between the corresponding pairs of columns (3.6.1).

6. A method for connecting a large diameter pipeline in a small cross-section tunnel according to claim 5, characterized in that: The upper end of the pipeline transport vehicle (1) is 50 mm higher than the upper end of the pier body (3.1).

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