A construction method for threading a continuously wound fiberglass pipe inside a large-diameter concrete pipe

Abstract

The present invention discloses a construction method for threading a continuous winding fiberglass pipe inside a large-diameter concrete pipe, which includes steps such as hoisting the fiberglass pipe, installing the fiberglass pipe, and grouting. Among them, grouting is to divide the entire pipe section into m grouting areas for n times of grouting. During construction, quantitative grouting is carried out from the grouting holes in the corresponding grouting sections according to the calculated set grouting volume, and grouting is stopped after reaching the grouting volume. The slurry for each grouting makes it self-level in each grouting section. When the slurry starts to gel, the next grouting is carried out, and so on until the n times of grouting are completed. The construction method of the present invention adopts a multi-segment and multi-time grouting method, with internal grouting of the inner pipe, which can accurately control the grouting position and grouting volume, effectively avoid the problem of grouting-induced pipe floating, and the grouting pipe failure is convenient for maintenance. The multi-segment grouting ensures uniform filling of the grouting over the entire pipe section; secondly, it can select the fiberglass pipe with the maximum length according to the diameter range of the working well, reduce the installation times, and save working hours.

Description

Technical Field

[0001] The invention belongs to a method for constructing and installing a continuously wound glass fiber reinforced plastic pipe in an inner pipe, and specifically relates to a construction method for inserting a continuously wound glass fiber reinforced plastic pipe in a large-diameter concrete pipe. Background Art

[0002] Nowadays, in the construction and installation of large-diameter concrete pipes through FRP pipes, hydraulic cylinders are used to install FRP pipes in the working well and directly push them into the concrete pipes. 1. The FRP pipes are the third-generation continuously wound FRP pipes, which use full-width rubber sleeve joints for connection and sealing. The sleeve joints are not fixed to the pipes and are commonly used in excavation pipe projects. However, in the process of pipe penetration and jacking, the sleeve joints and the pipes are prone to left and right deviations, which cannot meet the installation standards, and easily cause construction defects of the pipes, resulting in long-term rework of the project. 2. Since the hydraulic cylinder needs to be set with a backrest and the length of its own cylinder, the installation space of the FRP pipe in the working well is compressed, which directly shortens the length of the pipe, thereby increasing a lot of installation work, which not only costs extra installation costs but also easily leads to delays in the construction period. 3. In the process of the FRP pipe being directly pushed into the concrete pipe, the gravel or slag in the concrete pipe is easy to damage the outer surface of the FRP pipe. 4. Due to the use of hydraulic cylinder jacking, the longer the jacking distance, the greater the jacking force used. Once the cylinder jacking force exceeds the maximum jacking force that the FRP pipe can withstand, it is very easy to cause damage to the overall structure of the pipeline. Therefore, the jacking length of the project is very limited. 5. The subsequent grouting work between the two types of pipes adopts external grouting. External grouting requires tying the grouting pipe on the FRP pipe. The grouting pipe is pre-buried in the upper part of the FRP pipe along with the pipeline. If the grouting process is paused for too long, it is very easy for the cement slurry in the grouting pipe to solidify, which requires the grouting pipe to be reinserted. This grouting method is cumbersome and time-consuming. It is also difficult to accurately control the grouting position and grouting amount, which can easily cause the entire pipeline to float to varying degrees, directly affecting the quality of pipeline installation. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a construction method for inserting a continuously wound fiberglass reinforced plastic pipe into a large-diameter concrete pipe in view of the deficiencies in the above-mentioned prior art, which can accurately control the grouting position and grouting amount, and effectively avoid the problem of grouting floating pipe.

[0004] Another technical problem to be solved by the present invention is to improve the installation method of the FRP pipe, which can speed up the installation efficiency of the project pipeline, effectively solve the limitation of the FRP pipe in the pipe threading length, and greatly reduce the risk of pipeline damage.

[0005] The technical solution adopted by the present invention is: a construction method for inserting a continuously wound glass fiber reinforced plastic pipe in a large-diameter concrete pipe, comprising the following steps:

[0006] A. Hoisting of fiberglass pipe: Hoist the fiberglass pipe into the working well;

[0007] B. Installation of fiberglass pipe: Ship multiple sections of fiberglass pipe into the concrete pipe and connect them end to end in sequence;

[0008] C. Grouting: After the installation of the fiberglass pipe is completed, promptly carry out grouting construction to fill the gap between the fiberglass pipe and the concrete pipe with neat cement slurry; Divide the entire pipe section into m grouting areas for n times of grouting, where both m and n are greater than 1. The grouting section m is equally divided into m grouting areas according to the length of each grouting area not exceeding 60m based on the length of the entire pipe section; The number of grouting times n is determined according to the height Hi of each grouting obtained from anti-floating calculation and based on the total height of the cross-section of the entire concrete outer pipe and the slope of the pipe section; Calculate the grouting volume of each grouting in each grouting section according to the above division of the grouting section and the number of grouting times. During construction, quantitatively grout from the grouting holes in the corresponding grouting section according to the calculated grouting volume, and stop grouting when the grouting volume is reached. The slurry of each grouting levels itself by gravity in each grouting section, and the next grouting is carried out after the initial gelation of the slurry, and so on until the n -th grouting is completed.

[0009] Preferably, before hoisting the fiberglass pipe in step A, adjustable double - row guide rails are set at certain intervals along the entire length inside the concrete pipe. Adjust the support height of the guide rails to ensure that the entire guide rail is smooth inside the pipe. Before the formal hoisting operation of the fiberglass pipe, conduct a trial hoist. When the pipe is hoisted into the working well, it is strictly prohibited for people to stand inside the well. When the pipe is less than 50 cm away from the guide rail, the operator can approach for debugging and operation.

[0010] Preferably, the specific installation method of the fiberglass pipe in step B is as follows:

[0011] a. Directly place the fiberglass pipe on two manual forklifts inside the working well. Connect the forklifts with the winch of the receiving well and quickly transport the pipe to the starting point position of the adjustable double - row guide rails arranged along the entire length inside the large - diameter concrete pipe;

[0012] b. Place a retaining frame to fix the first pipe;

[0013] c. Withdraw the manual forklift, then ship the next pipe into the concrete pipe. When approaching the previous pipe, place the pipe on the adjustable double - row guide rails; Withdraw the manual forklift, and so on, ship multiple sections of fiberglass pipe into the concrete pipe;

[0014] d. Use the winch to connect the cross - shaped tooling frame to hold the tail end of the pipe to be installed and carry out joint socket installation of the second pipe and the first pipe; According to this method, connect the fiberglass pipes end to end in sequence inside the concrete pipe.

[0015] Preferably, in step B, the glass steel pipes are connected by a sleeve type. A pure glass fiber reinforced plastic (FRP) collar and a wedge-shaped ethylene propylene diene monomer (EPDM) rubber seal ring are used for joint connection. The outer diameter of the pure FRP collar is the same as the outer diameter of the glass steel pipe. The wedge-shaped EPDM rubber seal ring is placed in the groove at the end of the pipe, and the pipe socket is fully coated with a neutral lubricant.

[0016] Preferably, before grouting, concrete plugs need to be set at both ends of the entire section of the glass steel pipeline, and observation holes are opened at the top.

[0017] Preferably, in step C, for the first section of the grouting area, the direct grouting method with a galvanized pipe installed on the top outside the pipe is adopted, and the grouting volume is the first grouting volume calculated by design; for the 2nd to mth sections of the grouting area, the grouting method of injecting slurry outward through the grouting holes inside the pipe is adopted. The glass steel pipes at the ends of these m - 1 sections of the grouting area are all provided with left grouting holes, right grouting holes and top overflow holes; the mortar grouting machine is connected to the galvanized pipe, and the galvanized pipe is distributed along the grouting area of the entire pipeline. A flow splitting tee is set at the 2nd to mth grouting holes, and at each tee, a high-pressure hose is used to connect to the left grouting hole and the right grouting hole at the top of the pipe. Switches are provided at each tee and grouting hole. According to the designed and calculated sectional and sub - grouting volume table, that is, the grouting volume in each grouting section for each grouting time, the requirement of accurate volume control is achieved by opening and closing the switches. The grouting volumes in the 2nd to n grouting areas are all the grouting volumes calculated by design.

[0018] Preferably, the height Hi of each grouting in step C is obtained by the following anti - floating calculation: calculating that the buoyancy W of the neat cement slurry for the inner pipe in a single grouting is less than the self - weight G of the pipeline divided by the safety factor of 1.1 is considered to meet the anti - floating calculation;

[0019] The calculation of the single - time grouting height Hi is carried out according to the following steps: The simplified analysis diagram of the buoyancy Fy of the neat cement slurry on the inner pipe is as Figure 1 shown;

[0020] Among them:

[0021] F: is the radial pressure in the wet perimeter area where the neat cement slurry contacts the inner pipe;

[0022] Fy: is the vertical component of the radial pressure in the wet perimeter area where the neat cement slurry contacts the inner pipe. The resultant force W of its integral along the length of the wet perimeter in contact with the inner pipe is the buoyancy of the neat cement slurry on the inner pipe;

[0023] Let the self - weight of the pipeline be G;

[0024] The single - time grouting height Hi is calculated by the following formula:

[0025]

[0026] The buoyancy W of the neat cement slurry on the inner pipe is calculated by the following formula;

[0027]

[0028] ρ: density of the grouting liquid;

[0029] θ1: central angle of the pipe corresponding to the starting position of grouting;

[0030] θ2: central angle of the pipe corresponding to the ending position of grouting;

[0031] R: outer radius of the pipe.

[0032] Preferably, high-quality thixotropic neat cement slurry is used as the grouting material, and the mixing ratio of its constituent materials is cement: fly ash: water = 1.1:1:0.9. The initial setting time of the neat cement slurry with this mixing ratio is 45 minutes, and it has good fluidity.

[0033] Preferably, when the grouting time is paused for a long time, a large amount of clean water needs to be injected into the mixer for stirring and cleaning, and the grouting machine is started to flush the connected delivery pipe together to avoid the setting of the neat cement slurry inside the structure of the grouting machine and in the delivery pipe.

[0034] With the above structural design, compared with the prior art, it has the following advantages: First, the construction method of the present invention adopts a multi-stage and multi-time grouting method, grouting inside the inner pipe, which can accurately control the grouting position and the amount of grouting, effectively avoid the problem of grouting pipe floating, and the grouting pipe failure is convenient for maintenance. The multi-stage grouting ensures uniform filling of the grouting in the entire pipe section. Second, it can select the glass steel pipe with the maximum length according to the diameter range of the working well, reduce the number of installations, and save working hours. The outer diameter of the glass steel pipe it uses is the same as the outer diameter of the pure glass steel sleeve joint, and the two pipes are inserted and installed on the smooth guide rail, which ensures the efficiency of socket adjustment, realizes the installation process inside the casing, and its use of a wedge-shaped ethylene propylene diene monomer rubber ring is convenient for socket insertion and can meet the water sealing conditions. During installation construction, the glass steel pipe is directly placed on two manual forklifts in the working well, and the manual forklifts are connected to the winch of the receiving well and quickly transported to the starting point position of the adjustable double-row guide rail. A retaining frame is set to fix the first pipe, and the winch is used to connect the cross tooling frame to hold the pipe to be installed for installation, which speeds up the installation speed and shortens a large amount of construction period. Description of the Drawings

[0035] Figure 1 It is a simplified calculation and analysis diagram of the buoyancy Fy of the neat cement slurry on the inner pipe.

[0036] Figure 2 It is a schematic diagram of segmented and multiple grouting.

[0037] Figure 3 It is Figure 2 The enlarged view at position A in Detailed Embodiments

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0039] A construction method for threading a continuous filament-wound fiberglass pipe inside a large-diameter concrete pipe. Taking the example of threading a DN2800 continuous filament-wound fiberglass-reinforced plastic sand-filled pipe inside a DN3200 reinforced concrete pipe, the self-weight of the DN2800 inner pipe is 700 kg / m, the pipe section length is 437 m, and the slope is 0.0037. The method includes the following steps:

[0040] A. Hoisting of the fiberglass pipe: Hoist the fiberglass pipe into the working well; before hoisting the fiberglass pipe, adjustable double-row guide rails with a certain spacing (1050 mm in this embodiment) and a diameter of Φ50 mm are set along the entire length inside the concrete pipe. Adjust the support height of the guide rails to ensure that the entire guide rail is smooth inside the pipe. Before the formal hoisting operation of the fiberglass pipe, a trial hoist is first carried out. When the pipe is hoisted into the working well, no one is allowed to stand inside the well. When the pipe is less than 50 cm away from the guide rail, the operator can approach for debugging and operation;

[0041] B. Installation of the fiberglass pipe: Transport multiple sections of the fiberglass pipe into the concrete pipe and connect them end to end in sequence;

[0042] a. Directly place the fiberglass pipe on two manual forklifts inside the working well. The forklifts are connected to the winch of the receiving well, and quickly transport the pipe to the starting point position of the adjustable double-row guide rails arranged along the entire length inside the large-diameter concrete pipe;

[0043] b. Place a retaining frame to fix the first pipe;

[0044] c. The manual forklift withdraws, and then transports the next pipe into the concrete pipe. When approaching the previous pipe, place the pipe on the adjustable double-row guide rails; the manual forklift withdraws, and so on, transporting multiple sections of the fiberglass pipe into the concrete pipe;

[0045] d. Use the winch to connect the cross tooling frame to hold the tail end of the pipe to be installed, and perform joint socket installation of the second pipe and the first pipe; in this way, connect the fiberglass pipes end to end in sequence inside the concrete pipe; among them, the fiberglass pipe adopts a sleeve connection, and a pure fiberglass sleeve ring and a wedge-shaped ethylene propylene diene monomer rubber seal are used for joint connection. The outer diameter of the pure fiberglass sleeve ring is the same as the outer diameter of the fiberglass pipe. The wedge-shaped ethylene propylene diene monomer rubber seal is placed in the groove at the end of the pipe, and the pipe socket is fully coated with a neutral lubricant;

[0046] C. Grouting: After the glass steel pipe is jacked and installed, grouting construction shall be carried out in a timely manner to fill the gap between the glass steel pipe and the concrete pipe with cement. Before grouting, concrete plugs shall be set at both ends of the entire pipeline of the glass steel pipe, and observation holes shall be opened at the top. The entire pipeline shall be divided into 8 grouting zones for 8 times of grouting. Each time of grouting shall be quantitatively grouted according to the calculated grouting volume. The slurry for each time of grouting shall be self-leveled. After the slurry initially gels, the second grouting shall be carried out, and so on until the 8 times of grouting are completed. For the first grouting zone, the direct grouting method of installing a Φ50mm galvanized pipe outside the top of the pipe shall be adopted; for the 2nd to 8th grouting zones, the grouting method of injecting slurry outward through the grouting holes inside the pipe shall be adopted. The glass steel pipes at the ends of these 7 grouting zones are all provided with left grouting holes, right grouting holes and top overflow holes. The mortar grouting machine is connected to a Φ40mm galvanized pipe, and the galvanized pipe is distributed along the grouting zones of the entire pipeline. A flow dividing tee shall be set at the 2nd to 8th grouting holes, and a high-pressure hose shall be used to connect to the left grouting hole and the right grouting hole at the top of the pipe at each tee. Switches shall be provided at each tee and grouting hole. According to the designed and calculated sectional and staged grouting volume table, the requirement of accurate quantity control shall be achieved by opening and closing the switches; as Figure 2 and Figure 3 shown.

[0047] The height Hi of each grouting shall be obtained by the following anti-floating calculation: Calculating that the buoyancy W of the neat cement slurry for a single grouting on the inner pipe is less than the self-weight G of the pipeline divided by 1.1 (safety factor) means meeting the anti-floating calculation.

[0048] The calculation of the single grouting height Hi shall be carried out according to the following steps: The simplified analysis diagram of the buoyancy Fy of the neat cement slurry on the inner pipe is as Figure 1 shown.

[0049] Among them:

[0050] F: is the radial pressure of the contact wet perimeter area between the neat cement slurry and the inner pipe

[0051] Fy: is the vertical component force of the radial pressure of the contact wet perimeter area between the neat cement slurry and the inner pipe. The resultant force W of its integral along the length of the contact wet perimeter of the inner pipe is the buoyancy of the neat cement slurry on the inner pipe

[0052] Let the self-weight of the pipeline be G

[0053] The single grouting height Hi is calculated by the following formula:

[0054]

[0055] The buoyancy W of the neat cement slurry on the inner pipe is calculated by the following formula

[0056]

[0057] ρ: is the density of the grouting liquid;

[0058] θ1: The central angle of the pipe corresponding to the starting position of grouting;

[0059] θ2: The central angle of the pipe corresponding to the ending position of grouting;

[0060] R: Outer radius of the pipe

[0061] For example:

[0062] ρ = 1500 kg / m3, the outer diameter of the inner pipe is 2826 mm, the radius R = 1413, and the self-weight of the pipe per meter is 700 kg. First, calculate the grouting height control parameters when the pipe is horizontal:

[0063] H1 = 320, θ1 = 0, ,

[0064] For the first grouting, the slurry starts from the bottom of the pipe, i.e., θ1 = 0; let the cut-off angle of the first grouting be θ2 = ɑ

[0065] Then the buoyancy force:

[0066]

[0067]

[0068] Then, W = 592 kg / m < 700 / 1.1 = 636.36 kg / m, meeting the anti-floating requirement.

[0069] For the second grouting, the slurry starts from the cut-off angle ɑ of the first time, and let the cut-off angle of the second time be θ2 = β

[0070] Then the buoyancy force:

[0071]

[0072]

[0073] Take β = 73.32°, then W = 600 kg / m < 700 / 1.1 = 636.36 kg / m, meeting the anti-floating requirement.

[0074] The height difference of the second grouting compared with the first grouting

[0075]

[0076] Since after the grouting liquid is higher than the horizontal diameter of the inner pipe, the resultant force of the action on the inner pipe will be a downward pressure, not a buoyancy force. Therefore, it is only necessary to calculate whether the buoyancy force at the horizontal diameter is safe. For the third grouting, the slurry starts from the cut-off angle β = 73.32° of the second time, and the cut-off angle of the third time is at the horizontal diameter, i.e., θ2 = 90°

[0077] Then the buoyancy force:

[0078]

[0079] Then W = 50 kg / m < 700 / 1.1 = 636.36 kg / m, meeting the anti-floating requirement.

[0080] Therefore, the third grouting can be directly grouted to the top of the pipe.

[0081] Since the pipeline usually has a slope, calculate the anti-floating position of the lowest cross-section of each segment according to the slope of the pipeline to calculate the number of grouting times required for each segment. In this example, the slope of the pipeline is 0.0037 and the pipe section length is 437 m. According to the following table, 8 times of grouting are required. The height of each grouting is shown in the following table. The height of the first segment is the height from the inner wall of the outer pipe, which is related to the height of the inner pipe placed in the outer pipe. In this example, the guide rail with a spacing of 1050, and the outer wall of the inner pipe is 39.539 mm away from the inner wall of the outer pipe at the lowest part.

[0082] According to the above grouting division by times and segments, the grouting volume of each segment and each time can be calculated as follows (the volume can be directly measured using 3D drawing software):

[0083]

[0084] Preferably, high-quality thixotropic cement slurry is used as the grouting material, and the mixing ratio of its constituent materials is cement: fly ash: water = 1.1:1:0.9. The initial setting time of the cement slurry with this mixing ratio is 45 min, and it has good fluidity.

[0085] Preferably, when the grouting time is paused for a long time, a large amount of clean water needs to be injected into the mixer for stirring and cleaning, and the grouting machine is started to flush the connected delivery pipe together to prevent the cement slurry from solidifying inside the structure of the grouting machine and in the delivery pipe.

[0086] First, the construction method of the present invention adopts a multi-stage and multi-time grouting method, with grouting inside the inner pipe, which can accurately control the grouting volume position and the grouting volume, effectively avoid the problem of grouting pipe floating, and is convenient for repairing the grouting pipe failure. The multi-stage grouting ensures uniform filling of the grouting in the entire pipe section. Secondly, it can select the glass steel pipe with the maximum length according to the diameter range of the working well, reduce the installation times, and save working hours. The outer diameter of the glass steel pipe used is the same as the outer diameter of the pure glass steel sleeve joint, and the two pipes are inserted and installed on a smooth guide rail, which ensures the efficiency of socket adjustment and realizes the installation process inside the casing. The use of a wedge-shaped ethylene propylene diene monomer (EPDM) rubber ring not only facilitates socket insertion, but also meets the water sealing conditions. During installation and construction, the glass steel pipe is directly placed on two manual forklifts in the working well. The manual forklifts are connected to the winch of the receiving well and quickly transported to the starting point position of the adjustable double-row guide rail. A retaining frame is set to fix the first pipe, and the winch is used to connect the cross tooling frame to hold the pipe to be installed for installation, which speeds up the installation speed and shortens a large amount of construction period.

[0087] In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inner", "front", "center", "both ends", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0088] In the present invention, unless otherwise clearly specified and defined, the terms "installation", "setting", "connection", "fixation", "swivel connection", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, for those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0089] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A construction method for threading a continuous filament wound fiberglass pipe inside a large-diameter concrete pipe, characterized in that: It includes the following steps: A. Hoisting of the fiberglass pipe: Hoist the fiberglass pipe into the working well; B. Installation of the fiberglass pipe: Directly place the fiberglass pipe on two manual forklifts in the working well. Connect the forklifts to the winch of the receiving well and quickly transport the pipe to the starting point of the adjustable double-row guide rails arranged along the entire length inside the large-diameter concrete pipe; Place a retaining frame to fix the first pipe; Withdraw the manual forklift, then load and transport the next pipe into the concrete pipe. When approaching the previous pipe, place the pipe on the adjustable double-row guide rails; Withdraw the manual forklift, and so on, load and transport multiple sections of fiberglass pipes into the concrete pipe; Use the winch to connect to the cross tooling frame to hold the tail end of the pipe to be installed and perform socket and spigot joint installation of the second pipe and the first pipe; In this way, connect the fiberglass pipes end to end in sequence inside the concrete pipe; C. Grouting: After the installation of the fiberglass pipe is completed, promptly carry out grouting construction to fill the gap between the fiberglass pipe and the concrete pipe with neat cement slurry; Divide the entire pipe section into m grouting areas for n times of grouting, where both m and n are greater than 1. The grouting section m is divided into m grouting areas at equal intervals according to the entire pipe section length, with the length of each grouting area not exceeding 60m; The number of grouting times n is obtained according to the anti-floating calculation of the height Hi of each grouting and is determined according to the total height of the cross-section of the entire concrete outer pipe and the pipe section slope; Calculate the grouting volume of each grouting in each grouting section according to the above division of the grouting section and the number of grouting times. During construction, quantitatively grout from the grouting holes in the corresponding grouting section according to the calculated grouting volume, and stop grouting when the grouting volume is reached. Let the slurry self-level in each grouting section during each grouting. When the slurry starts to gel, carry out the next grouting, and so on until n times of grouting are completed.

2. The construction method according to claim 1, wherein: Before hoisting the fiberglass pipe in step A, set adjustable double-row guide rails at certain intervals along the entire length inside the concrete pipe, adjust the support height of the guide rails to ensure the smoothness of the entire guide rails inside the pipe. Before the formal hoisting operation of the fiberglass pipe, conduct a trial hoisting. When the pipe is hoisted to the working well, it is strictly prohibited for people to stand inside the well. When the pipe is less than 50 cm away from the guide rails, the operator can approach for debugging and operation.

3. The construction method according to claim 1, characterized in that: In step B, the fiberglass pipes are connected by a sleeve type, and a pure fiberglass sleeve ring and a wedge-shaped ethylene propylene diene monomer rubber sealing ring are used for joint connection. The outer diameter of the pure fiberglass sleeve ring is the same as the outer diameter of the fiberglass pipe. The wedge-shaped ethylene propylene diene monomer rubber sealing ring is placed in the groove at the end of the pipe, and the pipe socket is fully coated with a neutral lubricant.

4. The construction method according to claim 1, characterized in that: Before grouting, it is necessary to set concrete plugs at both ends of the entire pipeline of the fiberglass pipe and open observation holes at the top.

5. The construction method according to claim 1, characterized in that: In the first grouting area of step C, the direct grouting method with a galvanized pipe installed on the top outside the pipe is adopted, and the grouting volume is the first grouting volume calculated by design; in the 2nd to mth grouting areas, the grouting method of injecting slurry outward through the grouting holes inside the pipe is adopted. The fiberglass pipes at the ends of the 2nd to mth grouting areas are all provided with left grouting holes, right grouting holes and top overflow holes; the mortar grouting machine is connected to the galvanized pipe, and the galvanized pipe is distributed along the whole pipeline grouting area. A flow splitting tee is set at the 2nd to mth grouting holes. High-pressure hoses are used to connect to the left grouting hole and the right grouting hole at the top of the pipe at each tee. Switches are provided at each tee and grouting hole. According to the designed and calculated sectional and staged grouting volume table, that is, the grouting volume in each grouting section for each grouting, the requirement of accurate volume control is achieved by opening and closing the switches. The grouting volume in the 2nd to nth grouting areas is all the grouting volume calculated by design.

6. The construction method according to claim 5, characterized in that: The height Hi of each grouting in step C is obtained by the following anti-floating calculation: calculating that the buoyancy W of the neat cement slurry for a single grouting on the inner pipe is less than the self-weight G of the pipeline divided by the safety factor of 1.1 is considered to meet the anti-floating calculation. The calculation of the single grouting height Hi is carried out according to the following steps: the calculation and analysis of the buoyancy Fy of the neat cement slurry on the inner pipe. Where: F: is the radial pressure of the neat cement slurry in the wet perimeter area in contact with the inner pipe; Fy: is the vertical component of the radial pressure of the neat cement slurry in the wet perimeter area in contact with the inner pipe. The resultant force W of its integral along the length of the wet perimeter in contact with the inner pipe is the buoyancy of the neat cement slurry on the inner pipe; Let the self-weight of the pipeline be G; The single grouting height Hi is calculated according to the following formula: ， The buoyancy W of the neat cement slurry on the inner pipe is calculated according to the following formula; ， ρ: is the density of the grouting liquid; θ1: is the pipe center angle corresponding to the grouting start position; θ2: is the pipe center angle corresponding to the grouting end position; R: is the outer radius of the pipeline.

7. The construction method according to claim 1, characterized in that: High-quality thixotropic neat cement slurry is used as the grouting material, and the mixing ratio of its constituent materials is cement: fly ash: water = 1.1:1:0.

9. The initial setting time of the neat cement slurry with this mixing ratio is 45 minutes, and it has good fluidity.

8. The construction method according to claim 1, characterized in that: When the grouting time is paused for a long time, a large amount of clean water needs to be injected into the mixer for stirring and cleaning, and the grouting machine is started to flush the connected delivery pipe together to prevent the neat cement slurry from solidifying inside the structure of the grouting machine and in the delivery pipe.

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