Construction method and construction device of ground source heat exchange pipe

Abstract

This application relates to the field of ground source heat exchanger pipe construction, and discloses a construction method and apparatus for ground source heat exchanger pipes. The method includes: completing drilling and cleaning the borehole, leaving a sediment-containing section at the bottom; guiding and lowering the heat exchanger pipe using a guiding device at the borehole opening and correcting any deviation; dividing the borehole wall from bottom to top into a deep heat exchange section and a shallow insulation section; injecting a preset dose of silicon-based interface activator into the deep heat exchange section and coordinating with air-lift disturbance for borehole cleaning; injecting a low dose of activator into the shallow insulation section and allowing it to soak; independently preparing high-thermal-conductivity grout and low-thermal-conductivity grout; pumping the high-thermal-conductivity grout at a first grouting pressure to fill the sediment section and deep heat exchange section; when grouting reaches the boundary, switching to extracting the low-thermal-conductivity grout without stopping the pump; continuously pumping the low-thermal-conductivity grout at a lower second grouting pressure until the shallow insulation section is filled. This application achieves segmented treatment and layered continuous grouting of the ground source borehole.

Description

Technical Field

[0001] This application relates to the field of ground source heat exchanger pipe construction, specifically to a construction method and device for ground source heat exchanger pipes. Background Technology

[0002] Ground source heat pump systems exchange heat with the soil and rock by burying heat exchange pipes underground. In the construction of medium-deep buried pipes, after drilling is completed and the heat exchange pipes are placed in the borehole, grouting material is used to backfill the annular gap outside the pipes, so that the heat exchange pipes are bonded to the original soil and rock mass.

[0003] In traditional construction processes, uniformly prepared grouting material is typically used to backfill the entire borehole. However, the underground environment is complex, and mud inevitably adheres to the borehole wall during drilling. In actual operation after construction, the buried pipe system faces several challenges: firstly, the heat transfer resistance between the heat exchange pipes and the surrounding soil and rock is relatively high, affecting effective heat transfer; secondly, due to alternating external climatic conditions, geothermal wells are prone to energy loss in shallow areas. This results in lower actual heat exchange efficiency and increased operating energy consumption for the ground source heat pump system.

[0004] Therefore, how to improve the operational efficiency of ground source heat pump systems is a technical problem that needs to be solved. Summary of the Invention

[0005] In order to solve the technical problems in the prior art, this application provides a construction device for a ground source heat exchanger pipe.

[0006] The construction method and apparatus for a ground source heat exchanger pipe provided in this application adopt the following technical solution:

[0007] A construction method for a ground source heat exchanger pipe includes the following steps:

[0008] S1. Complete drilling and perform reverse circulation cleaning, leaving a sediment-containing section at the bottom of the hole;

[0009] S2. A guiding device is set at the orifice to guide and constrain the heat exchange tube and lower it into the borehole. During the lowering process, the heat exchange tube is offset and corrected.

[0010] S3. Divide the borehole wall from bottom to top into a deep heat exchange section and a shallow insulation section;

[0011] S4. A preset dose of silicon-based interface activator is injected from bottom to top into the deep heat exchange section, and the hole is cleaned simultaneously with air lift disturbance;

[0012] S5. Inject the silicon-based interface activator at a dose lower than the preset amount into the shallow insulation section, and let it stand and soak without mechanical disturbance;

[0013] S6. High thermal conductivity grout and low thermal conductivity grout are prepared and stored independently in a main mixing tank and an insulation grout mixing tank, respectively;

[0014] S7. Start a grouting pump to extract the high thermal conductivity grouting material and pump it at the first grouting pressure to simultaneously fill the sediment receiving section and the deep heat exchange section;

[0015] S8. When the grouting is raised to the boundary between the deep heat exchange section and the shallow insulation section, the suction end of the grouting pump is switched to the insulation grout mixing tank without stopping the pump, and the low thermal conductivity grout is extracted.

[0016] S9. Control the grouting pump to continuously pump the low thermal conductivity grout at a second grouting pressure lower than the first grouting pressure until the shallow insulation section is completely filled.

[0017] By adopting the above technical solutions, S1 retains a sediment-accommodating section at the bottom of the borehole, providing space for the residue to accumulate on the borehole wall of the heat exchange section, thus increasing the contact thermal resistance. It also provides a buffer for grouting and prevents voids from being filled at the bottom of the borehole. S2 installs a guiding device at the borehole opening to guide and constrain the heat exchange tubes, and corrects any deviations during the lowering process to prevent eccentric adhesion and entanglement, ensuring the pipes are centered, straight, and have uniform annular gaps. S3 to S5 divide the borehole wall into a deep heat exchange section and a shallow insulation section, treating them differently: the deep heat exchange section uses sufficient activator combined with air-lift agitation to peel off the mud cake, reducing the thermal resistance at the pipe-soil interface and enhancing heat exchange. The shallow insulation section is treated with a small amount of activator by static soaking and gentle treatment to retain its shallow insulation properties and avoid over-activation that could create heat conduction channels and increase wellhead losses. This allows for both deep heat exchange and shallow loss reduction within the same well. In S6, high-thermal-conductivity and low-thermal-conductivity grouting materials are prepared independently in two mixing tanks to prevent premature mixing failure. In S7 to S9, the two types of grouting materials are filled in corresponding zones: first, the high-thermal-conductivity grouting material is pumped at the first grouting pressure to fill the sediment containment section and the deep heat exchange section. After being pumped to the boundary between the two sections, the low-thermal-conductivity grouting material is extracted by switching the suction end without stopping the pump, and the pressure is reduced to the second grouting pressure to fill the shallow insulation section. Continuous pumping without stopping the pump avoids faults at the boundary, ensures dense filling, and eliminates the need for pump shutdown and pipe cleaning. The lower second grouting pressure also avoids destroying the borehole wall interface formed by the gentle activation of the shallow layer.

[0018] Preferably, in step S7, the first grouting pressure is set in segments according to the burial depth of the borehole, and the grouting pipe is raised from the bottom of the hole at a constant speed; when the pressure suddenly drops during the grouting process, the raising is paused and the pressure is stabilized and grout is added; when the pressure continues to exceed the preset upper limit pressure, the grouting pipe is raised slowly; and the pressure is stabilized for a preset time after each preset height is raised.

[0019] By adopting the above technical solution, the deep heat exchange section has a large burial depth range, and the formation confining pressure and hydrostatic column pressure at different depths differ significantly. When grouting with uniform pressure, insufficient pressure at deep depths can easily lead to annular gaps and cavities, while excessive pressure at shallow depths may cause formation fracturing or damage to the borehole wall interface. By setting the first grouting pressure according to the burial depth segment, the grouting pipe automatically matches the corresponding pumping pressure as it is lifted segment by segment, ensuring that each segment is in the optimal filling state. The grouting pipe is lifted at a uniform speed from the bottom of the borehole to avoid cavities caused by rapid pipe pulling. When the pressure suddenly drops during grouting, it indicates that there are gaps and cavities or formation fractures in the current well section that absorb grout. Pausing the lifting and stabilizing the pressure to replenish grout can allow the grout to fully fill the cavity area and eliminate local defects. When the pressure continues to exceed the preset upper limit pressure, it indicates that there is blockage or grout solidification near the grouting pipe opening. Slowly lifting the grouting pipe can release the local pressure at the pipe opening and prevent the pipe from bursting. After each preset height is raised, the pressure is stabilized for a preset time. During continuous pumping, pressure is checked section by section to ensure that the overall porosity after grouting consolidation meets the design requirements, and to conduct layer-by-layer acceptance, timely detection and treatment of non-dense sections.

[0020] Preferably, after step S9, the following steps are also included: S10. After grouting is completed, allow the soil to settle for a preset time, remove the laitance at the borehole opening, and backfill the borehole opening with graded sand and gravel and undisturbed soil in layers to isolate the heat exchange channel between the surface air and the shallow strata.

[0021] By adopting the above technical solution, after grouting, the grout continues to bleed and compact under the action of hydrostatic pressure, allowing sufficient time for static settling to allow the grout in the borehole to fully solidify, expel residual air bubbles and free water, and avoid the formation of unfilled cavities in the borehole opening section after the grout level drops. After removing the floating grout at the borehole opening, graded sand and gravel and undisturbed soil are used for backfilling in layers, so that the backfill has good compaction and interlayer interlocking force, forming a solid heat insulation cap covering the low thermal conductivity grout. This provides a secondary insulation between the surface air and the shallow strata from the surface physical structure, preventing atmospheric temperature fluctuations from being directly conducted to the shallow heat exchange pipe section through the borehole opening and increasing heat loss. Together with the shallow low thermal conductivity grout, it forms a double heat insulation system, further reducing the annual heat loss at the wellhead.

[0022] A construction device for a ground source heat exchanger pipe, comprising:

[0023] The support mechanism includes a support frame, two first mounting rods, and two second mounting rods. The two first mounting rods are arranged parallel to each other and fixed to the support frame. The two second mounting rods are arranged parallel to each other and fixed to the support frame. The first mounting rods are perpendicular to the second mounting rods.

[0024] Two sets of guiding mechanisms are provided, each corresponding to one of the two first mounting rods. Each set of guiding mechanisms includes a flipping component and a fastening component. The flipping component is rotatably connected to the corresponding first mounting rod. The flipping component has two first semicircular grooves. The two ends of the fastening component are slidably connected to the two second mounting rods respectively. The fastening component has two second semicircular grooves that correspond one-to-one with the two first semicircular grooves. Each first semicircular groove and the corresponding second semicircular groove together form a guide hole for the heat exchange tube to pass through. The flipping component and the fastening component are detachably connected.

[0025] By adopting the above technical solution, the flipping component is rotatably connected to one of the first mounting rods, and can be flipped around the mounting rod to open the guide mechanism. The two ends of the fastening component are slidably connected to the two second mounting rods, and can move along the second mounting rods to fasten or separate from the flipping component. The two cooperate to allow the guide hole to open and close, which facilitates the insertion and removal of the heat exchange tube. The first semicircular groove and the second semicircular groove together form a guide hole, which provides circumferential constraint on the pipe during lowering and limits the lowering path of the pipe. The two sets of guide mechanisms correspond one-to-one with the two first mounting rods, and can guide the two pipes simultaneously. The flipping component and the fastening component are detachably connected, which facilitates the installation, disassembly and relocation of the device.

[0026] Preferably, the flipping component includes a guide portion and a flipping portion, and both first semi-circular grooves are formed in the guide portion; the flipping portion includes a sliding plate, a connecting plate and a fixing member, the sliding plate is rotatably connected to the first mounting rod, the connecting plate is slidably engaged with the sliding plate, the guide portion is fixed to the connecting plate, and the fixing member is used to limit and fix the connecting plate to the sliding plate.

[0027] By adopting the above technical solution, the connecting plate can extend and retract along its own axis, thereby changing the horizontal normal distance of the guide part relative to the first mounting rod. This design allows construction personnel to independently fine-tune the relative distance between the two sets of guide holes according to the specific borehole diameter of the geothermal well or the designed heat exchange tube spacing, so that a single set of construction equipment can adapt to various specifications of pipe spacing requirements.

[0028] Preferably, the guide portion has a first mounting ear at each end, and the fastener has a second mounting ear at each end, with the first mounting ear and the second mounting ear being detachably connected; both the first mounting ear and the second mounting ear have slots, and both can be slidably connected to the two second mounting rods through the corresponding slots.

[0029] By adopting the above technical solution, both the first mounting ear and the second mounting ear are connected to the second mounting rod through a slot, so that the fastener can slide along the second mounting rod after being separated from the flipping part, which facilitates the opening and closing of the guide hole. The slot connection method facilitates the quick alignment and fastening of the first mounting ear and the second mounting ear, and also facilitates the removal of the fastener for installation and removal after the two are separated. When the heat exchange tube is lowered and generates severe friction and dragging force, the downward pressure and lateral shaking force around the guide hole are directly transmitted and dispersed to the second mounting rod of the support frame through the above-mentioned overlapping structure.

[0030] Preferably, each set of guiding mechanisms further includes two adjusting components, each of which is respectively configured to correspond one-to-one with the two guiding holes; each adjusting component includes four housings, and a first guiding unit, a second guiding unit, and a third guiding unit arranged sequentially from bottom to top along the axial direction of the guiding hole; the four housings are arranged in a circumferential array around the axis of the corresponding guiding hole, and two of the housings are fixed to the outer wall of the corresponding first semicircular groove, and the other two housings are fixed to the outer wall of the corresponding second semicircular groove.

[0031] By adopting the above technical solution, four shells are arranged in a circumferential array around the periphery of each guide hole. Two shells are fixed to the outer wall of the first semicircular groove, and the other two are fixed to the outer wall of the second semicircular groove. The first guide unit, the second guide unit, and the third guide unit are arranged sequentially from bottom to top along the axial direction of the guide hole. The four shells are arranged in a circumferential array, so that the lowered heat exchange tube is under multi-level constraints, and the position of the pipe is defined layer by layer. Since the four shells are respectively attached to the outer walls of the first and second semicircular grooves, when the flipping part flips and the fastening part slides to open the two semicircular grooves, each shell, together with the first guide unit, the second guide unit, and the third guide unit on it, separates synchronously with its respective semicircular groove. This takes into account the layered arrangement of the first guide unit, the second guide unit, and the third guide unit along the axial direction of the guide hole and the multi-directional distribution of the four shells along the circumference, as well as the overall quick assembly and disassembly.

[0032] Preferably, the first guiding unit includes four first connectors and four first guide rollers. The four first connectors are arranged in a one-to-one correspondence with the four housings. One end of each first connector is fixed to the bottom of the corresponding housing, and the other end is rotatably connected to the corresponding first guide roller.

[0033] By adopting the above technical solution, when the heat exchange tube wall moves down close to the edge of the guide hole, the four circumferentially distributed first guide rollers convert the sliding friction between the tube and the hole wall into rolling friction. The first guide rollers in the four directions provide passive guidance and pre-centering, buffering the swing caused by the tube's own weight or external traction when it enters the hole, while reducing drag friction and preventing the outer wall of the tube from being scratched at the hole end.

[0034] Preferably, the construction device further includes a control unit, and the third guiding unit includes four third connectors, four third guide rollers, and four sensors; the four third connectors are arranged one-to-one with the four housings; each third connector includes a connecting section and a pressure-sensing section, the connecting section is fixed to the inner wall of the corresponding housing, the pressure-sensing section is rotatably connected to the corresponding third guide roller, and the pressure-sensing part of the sensor is sandwiched between the connecting section and the pressure-sensing section; all four sensors are communicatively connected to the control unit.

[0035] By adopting the above technical solution, the pressure-sensing part of the sensor is sandwiched between the connecting section and the pressure-sensing section, transforming the contact point of the third guide roller into a fulcrum for detecting force. When the descending heat exchange tube compresses a certain third guide roller due to deformation or displacement, the pressure is transmitted through the movable pressure-sensing section to the fixed connecting section and acts on the sensor sandwiched therein, thereby obtaining the compressive force value at that location. The four matrix-distributed measuring points collect the pressure status of the pipeline in four radial directions in real time, and through communication connection with the control unit, quantify and confirm the contour change and displacement tendency of the solid pipe wall as the data signal required by the control unit.

[0036] Preferably, the second guiding unit includes four second connectors, four second guide rollers, and four driving components. The four second connectors are arranged one-to-one with the four housings. One end of each second connector is connected to the driving component, and the other end is rotatably connected to the corresponding second guide roller. Each driving component is fixed to the housing and is used to drive the corresponding second connector to extend or retract radially along the guide hole. All four driving components are communicatively connected to the control unit.

[0037] By adopting the above technical solution, one end of the four second connectors is connected to the drive unit fixed in the shell, and the other end is rotatably connected to the corresponding second guide roller. The drive unit drives the second connectors to extend and retract radially along the guide hole, so that the second guide roller in the middle layer changes from passive following to active extension and retraction. When the heat exchange tube is not in the center of the guide hole, the drive unit, which is connected to the control unit, pushes the second connector, so that the second guide roller outputs thrust radially towards the tube center, pushing the offset tube wall back to the center position, thereby actively adjusting the position of the pipe during the guiding process and avoiding the pipe from being eccentrically attached to the wall during the lowering.

[0038] In summary, this application includes at least one of the following beneficial technical effects:

[0039] 1. The flipping component is rotatably connected to one of the first mounting rods and can be flipped around the mounting rod to open the guide mechanism. The two ends of the fastening component are slidably connected to the two second mounting rods and can move along the second mounting rods to engage or disengage with the flipping component. The two components work together to allow the guide hole to open and close, facilitating the insertion and removal of the heat exchange tube. The first semicircular groove and the second semicircular groove together form the guide hole, which provides circumferential constraint on the pipe during lowering and limits the lowering path of the pipe. The two sets of guide mechanisms correspond one-to-one with the two first mounting rods and can simultaneously guide the two pipes of the single U-tube. The flipping component and the fastening component are detachably connected, which facilitates the installation, disassembly and relocation of the device.

[0040] 2. S1: A sediment-receiving section is reserved at the bottom of the borehole to provide space for the residue, preventing it from accumulating on the borehole wall of the heat exchange section and increasing contact thermal resistance. This also provides a buffer for grouting and prevents voids from being filled at the bottom of the borehole. S2: A guiding device is installed at the borehole opening to guide and constrain the heat exchange tubes and correct any deviations during lowering, preventing them from eccentrically adhering to the wall or becoming entangled, ensuring the pipes are centered, straight, and have uniform annular gaps. S3 to S5: The borehole wall is divided into a deep heat exchange section and a shallow insulation section at designated boundaries and treated differently: In the deep heat exchange section, sufficient activator is used in conjunction with air-lift agitation to peel off the mud cake, reducing the thermal resistance at the pipe-soil interface and enhancing heat exchange; in the shallow insulation section... A small amount of activator is allowed to stand and soak gently to retain shallow insulation properties, avoiding over-activation that could create heat conduction channels and increase wellhead losses. This achieves both deep heat exchange and shallow loss reduction within the same well. In step S6, high-thermal-conductivity and low-thermal-conductivity grouting materials are prepared independently in two mixing tanks to prevent premature mixing failure. Steps S7 to S9 involve filling the two grouting materials in corresponding zones: first, the high-thermal-conductivity grouting material is pumped at the first injection pressure to fill the sediment containment section and the deep heat exchange section. Once it reaches the boundary between the deep heat exchange section and the shallow insulation section, the pump is switched to extract the low-thermal-conductivity grouting material without stopping, and the pressure is reduced to the second injection pressure to fill the shallow insulation section. Continuous pumping without stopping avoids faults at the boundary, ensures dense filling, and eliminates the need for pump shutdown and pipe cleaning. The lower second injection pressure also prevents damage to the borehole wall interface formed by the gentle activation of the shallow layer.

[0041] 3. The control unit presets the force threshold and back pressure duration, and uses four sensors to collect and compare the pressure data of each third guide roller on the heat exchange tube in real time. When the pipe is unwound and lowered from its coiled state, the control unit determines that the pipe is bending or bulging to that side when the pressure of one sensor exceeds the force threshold. It then controls the corresponding drive unit on that side to push out the second guide roller to apply back pressure to the core of the pipe. This back pressure acts on the bent part for the set duration, overcoming the springback stress after the pipe is unwound, and gradually straightening the tilted pipe section. After the set duration is reached, the drive unit resets and retracts, and the data collection and comparison are restarted to keep the pipe lowered straight.

[0042] 4. When two sensors at opposite ends of the same diameter simultaneously detect pressure exceeding the force threshold, it indicates that the pipe is not bent on one side, but rather compressed in opposite directions, causing the cross-section to be compressed into an ellipse. Based on this, the control unit determines that the cross-section is deformed and controls two drive components in the same direction as the two sensors to start simultaneously, causing the two opposite second guide rollers to press towards the pipe core at the same time, clamping the elliptical pipe wall from both sides to restore it to a circular shape. After the correction reaches the set duration, the two drive components synchronously reset and retract, avoiding the reduction of the internal flow area and the increase of water flow resistance caused by the cross-section deformation of the pipe, thus ensuring the water flow capacity of the entire pipeline. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the construction device for the ground source heat exchanger pipe provided in Embodiment 1 of this application;

[0044] Figure 2 This is a cross-sectional view of the guide hole in Embodiment 1 of this application;

[0045] Figure 3 This is a cross-sectional view of the location of the first guide unit in Embodiment 1 of this application;

[0046] Figure 4 This is a cross-sectional view of the location of the third guide unit in Embodiment 1 of this application;

[0047] Figure 5 This is a cross-sectional view of the location of the second guide unit in Embodiment 1 of this application;

[0048] Figure 6 This is a schematic diagram of the internal structure of the borehole after construction in Embodiment 2 of this application;

[0049] Explanation of reference numerals in the attached drawings: 1. Support mechanism; 11. Support frame; 12. First mounting rod; 13. Second mounting rod; 14. Caster wheel; 15. Anchor pile; 2. Guide mechanism; 21. Flipping component; 211. Guide section; 2111. First semi-circular groove; 2112. First mounting ear; 212. Flipping section; 2121. Sliding plate; 2122. Connecting plate; 2123. Fixing component; 22. Fastening component; 221. Second semi-circular groove; 222. Second mounting ear; 23. Guide hole; 24. Slot; 3. Adjustment group Components; 31. Housing; 32. First guide unit; 321. First connector; 322. First guide roller; 33. Second guide unit; 331. Second connector; 332. Second guide roller; 333. Drive unit; 34. Third guide unit; 341. Third connector; 3411. Connecting section; 3412. Pressure sensing section; 342. Third guide roller; 343. Sensing element; 4. Control unit; 5. Heat exchange tube; 6. Drilling hole; 61. Shallow insulation section; 62. Deep heat exchange section; 63. Sludge receiving section. Detailed Implementation

[0050] The following is in conjunction with the appendix Figures 1-6 This application will be described in further detail.

[0051] Example 1

[0052] Please see Figure 1 The construction device for the ground source heat exchange pipe provided in this application embodiment includes a support mechanism 1 and two sets of guiding mechanisms 2. The support mechanism 1 provides an installation support foundation for the guiding mechanisms 2, enabling the guiding mechanisms 2 to work stably. The two sets of guiding mechanisms 2 cooperate with the support mechanism 1 to guide and correct the heat exchange pipe 5, avoiding situations such as eccentricity, wall adhesion, and entanglement during the lowering process, ensuring the smooth lowering of the pipe and guaranteeing its heat exchange effect and service life.

[0053] The support mechanism 1 includes a support frame 11, two first mounting rods 12, and two second mounting rods 13. The support frame 11 is a steel welded frame structure, which is horizontally erected above the borehole 6 opening to ensure sufficient strength and stability. The bottom of the support frame 11 is equipped with casters 14 to facilitate the movement and relocation of the device on the construction site; at the same time, the bottom of the support frame 11 is also equipped with anchor piles 15 threaded to it, which can move vertically. After positioning, the anchor piles 15 are screwed downwards to drive them into the ground or press them against the concrete retaining wall of the borehole 6 opening, thus firmly fixing the support frame 11 to the borehole opening position through the anchor piles 15, ensuring that it can withstand downward pressure and lateral swaying force during the pipeline lowering process without displacement or overturning.

[0054] The two first mounting rods 12 and the two second mounting rods 13 are all stainless steel round rods, which are fixed on the support frame 11. The two first mounting rods 12 are parallel to each other, providing rotational support for the flipping part 21 of the guide mechanism 2. The two second mounting rods 13 are also arranged in parallel, providing a track for the sliding of the fastening part 22. The first mounting rods 12 are perpendicular to the second mounting rods 13, and the four mounting rods form a rectangular layout on the support frame 11 to facilitate the cooperation between the components.

[0055] Two sets of guiding mechanisms 2 are correspondingly arranged with two first mounting rods 12 to guide the two pipes simultaneously. Each set of guiding mechanisms 2 includes a flipping component 21 and a fastening component 22. The flipping component 21 is rotatably connected to one of the first mounting rods 12 and can flip around the first mounting rod 12 to facilitate the insertion and removal of the heat exchange tube 5. The flipping component 21 has two first semicircular grooves 2111, the diameter of which is designed and machined according to the commonly used heat exchange tube diameter. The two ends of the fastening component 22 are slidably connected to two second mounting rods 13, allowing it to slide smoothly along the second mounting rods 13. The fastening component 22 has two second semicircular grooves 221 that correspond one-to-one with the two first semicircular grooves 2111. When the fastening component 22 is fastened to the flipping component 21, each first semicircular groove 2111 and the corresponding second semicircular groove 221 together form a guide hole 23 for the heat exchange tube 5 to pass through. The guide hole 23 provides circumferential constraint on the pipe, limiting the lowering path of the pipe.

[0056] In use, the construction personnel first slide the fastening part 22 along the second mounting rod 13 to the side away from the flipping part 21, and then flip the flipping part 21 upward around the first mounting rod 12 to open it. At this time, the guide hole 23 is in an open state, and the heat exchange tube 5 can be directly inserted into the first semi-circular groove 2111 from the side. Then, flip the flipping part 21 back to its original position, push the fastening part 22 along the second mounting rod 13 to the position where it aligns with the flipping part 21, so that the second semi-circular groove 221 and the first semi-circular groove 2111 surround and form a complete guide hole 23. Then, the fastening part 22 and the flipping part 21 are locked and fixed, and the pipe is constrained in the guide hole 23 and lowered in the vertical direction.

[0057] The flipping component 21 includes a guide portion 211 and a flipping portion 212. The guide portion 211 is where the first semi-circular groove 2111 is formed. Its material can be a wear-resistant polymer plastic or metal to reduce friction with the heat exchange tube 5. The flipping portion 212 includes a sliding plate 2121, a connecting plate 2122, and a fixing component 2123. The surface of the sliding plate 2121 has a sliding groove, and one end of the sliding plate 2121 is provided with a bushing. The bushing is fitted around the outer periphery of the first mounting rod 12 and can rotate freely around the axis of the first mounting rod 12, thereby realizing the rotatable connection between the flipping component 21 and the first mounting rod 12. The cross-section of the connecting plate 2122 is T-shaped, and the sliding groove of the sliding plate 2121 is a T-shaped groove adapted to the T-shaped cross-section. The T-shaped head of the connecting plate 2122 is embedded in the T-shaped groove and can slide along the length direction of the sliding groove. At the same time, the displacement in the exit direction is restricted by the two sides of the T-shaped groove, so that the flipping portion 212 can extend and retract along its own length direction. The guide part 211 is fixed to the end of the connecting plate 2122 away from the sliding plate 2121. The surface of the connecting plate 2122 is provided with a threaded hole, and the fastener 2123 is a locking screw. The screw is screwed into the threaded hole and presses against the bottom surface of the slide groove to limit and fix the connecting plate 2122 to the sliding plate 2121, ensuring that the connecting plate 2122 will not slide arbitrarily during use.

[0058] When it is necessary to adjust the distance between the two sets of guide holes 23, the construction personnel loosen the fixing piece 2123, pull the connecting plate 2122 out of the groove or push it in to the required length, change the horizontal normal distance of the guide part 211 relative to the first mounting rod 12, and then tighten the fixing piece 2123 to lock the connecting plate 2122 in that position. Thus, the construction personnel can independently adjust the relative distance between the two sets of guide holes 23 according to the specific borehole diameter of the geothermal well or the designed heat exchange tube spacing, allowing the same construction device to adapt to various specifications of pipe spacing requirements.

[0059] The guide portion 211 has first mounting ears 2112 at both ends, and the fastener 22 has second mounting ears 222 at both ends. Both the first mounting ears 2112 and the second mounting ears 222 have slots 24. The slots 24 are U-shaped grooves that open downwards. The opening width of the U-shaped groove is slightly larger than the outer diameter of the second mounting rod 13, so that both the first mounting ears 2112 and the second mounting ears 222 can be fastened to the second mounting rod 13 from above and slide freely along the length of the second mounting rod 13. The corresponding first mounting ear 2112 and second mounting ear 222 are detachably connected by bolts. Specifically, both the first mounting ear 2112 and the second mounting ear 222 are provided with bolt through holes. When the flipping part 21 flips back to its original position and the fastening part 22 slides to the mating position, the bolt through holes on the first mounting ear 2112 and the second mounting ear 222 are aligned. The bolt passes through the aligned bolt through holes and the nut is tightened to lock and fix the two together. When disassembling, the nut is removed and the bolt is taken out to separate the first mounting ear 2112 and the second mounting ear 222.

[0060] When the fastening part 22 is fastened to the flipping part 21, the first mounting ears 2112 at both ends of the guide part 211 and the second mounting ears 222 at both ends of the fastening part 22 simultaneously overlap on the two second mounting rods 13. The downward pressure and lateral swaying force generated during the lowering of the heat exchange tube 5 are transmitted to the first mounting ears 2112 and the second mounting ears 222 through the guide hole 23, and then transmitted and distributed to the two second mounting rods 13 of the support frame 11 through the slot 24, and the support frame 11 bears the load as a whole.

[0061] Please see Figure 2Each guide mechanism 2 also includes two adjustment components 3, which are respectively configured one-to-one with the two guide holes 23. Each adjustment component 3 includes four housings 31, and a first guide unit 32, a second guide unit 33, and a third guide unit 34 arranged sequentially from bottom to top along the axial direction of the guide hole 23. The four housings 31 are arranged in a circumferential array around the axis of the corresponding guide hole 23, that is, the central angle between two adjacent housings 31 is 90°. Two housings 31 are fixed to the outer wall of the corresponding first semicircular groove 2111, and the other two housings 31 are fixed to the outer wall of the corresponding second semicircular groove 221. When the flipping part 21 flips and the fastening part 22 slides to open the two semicircular grooves, each housing 31, together with the first guide unit 32, the second guide unit 33, and the third guide unit 34 on it, separates synchronously with its respective semicircular groove, taking into account the layered arrangement of the guide units along the axial direction of the guide hole 23 and the multi-directional distribution of the four housings 31 along the circumference, as well as the quick assembly and disassembly of the whole.

[0062] Please see Figure 3 The first guide unit 32 is located at the lowest level along the axial direction of the guide hole 23, and includes four first connectors 321 and four first guide rollers 322. The four first connectors 321 are correspondingly arranged with the four housings 31. One end of each first connector 321 is fixed to the bottom of the corresponding housing 31, and the other end is rotatably connected to the corresponding first guide roller 322. The first connector 321 is a metal rod, with its fixed end welded to the bottom of the housing 31, and its free end connected to the corresponding first guide roller 322 via a pin, allowing the first guide roller 322 to rotate freely around the pin. The first guide rollers 322 are made of polyurethane material, with a smooth surface and a certain degree of elasticity. The roller surfaces of the four first guide rollers 322 face the axis of the guide hole 23, and the radial distance between each roller surface and the axis of the guide hole 23 is equal to or slightly less than the outer diameter of the heat exchange tube 5. As the heat exchange tube moves downward, the four circumferentially distributed first guide rollers 322 passively rotate along with the tube, converting the sliding friction between the heat exchange tube and the construction device into rolling friction, reducing drag friction, buffering the swing caused by the tube's own weight or external traction when it enters the hole, and preventing the outer wall of the tube from being scratched at the hole end.

[0063] Please see Figure 4The construction device also includes a control unit 4, which is a programmable logic controller (PLC) fixed on the support frame 11 or remotely connected by a handheld operating terminal of the construction personnel. The third guide unit 34 is located at the uppermost layer along the axial direction of the guide hole 23, and includes four third connectors 341, four third guide rollers 342, and four sensors 343. The four third connectors 341 are correspondingly arranged with the four housings 31, and each third connector 341 includes a connecting section 3411 and a pressure-sensing section 3412. The connecting section 3411 is fixed to the inner wall of the corresponding housing 31, and the pressure-sensing section 3412 is rotatably connected to the corresponding third guide roller 342. A gap is maintained between the pressure-sensing section 3412 and the connecting section 3411; they are not directly rigidly fixed. The sensor 343 is a thin-film pressure sensor, specifically comprising an electrically connected pressure-sensing sheet and a sensor body. In terms of installation layout, the sensor body is fixed inside the housing 31 to obtain structural protection of the housing 31; the pressure-sensing plate is attached and clamped between the connecting section 3411 and the pressure-sensing section 3412 of the third connector 341.

[0064] All four sensors 343 are communicatively connected to the control unit 4. Each sensor 343 and drive unit 333 uses a communication module to transmit data and receive commands from the control unit 4. Their power supply and signal lines converge along the outer wall of their respective housings 31 and connect to the main circuit of the control unit 4 via quick-connect aviation connectors. When the guide mechanism 2 is opened, the operator can easily separate the components by unplugging the quick-connect connectors at the boundary of the two semi-circular slots. After flipping and resetting, communication can be restored by reconnecting the connectors. Alternatively, each sensor 343 and drive unit 333 can also communicate with the control unit 4 via a wireless communication module and be independently powered by a built-in battery in the housing 31, thus eliminating the constraints of physical cable connections.

[0065] When the descending heat exchange tube 5 deforms or shifts and presses against a third guide roller 342, the radial pressure on the third guide roller 342 is transmitted to the pressure-sensing section 3412. The pressure-sensing section 3412 then transmits the force to the sensing element 343 sandwiched between itself and the connecting section 3411. The sensing element 343 converts the pressure value into an electrical signal and sends it to the control unit 4. The control unit 4 then obtains the real-time force data for that location. The four circumferentially distributed sensing elements 343 correspond to the four radial directions of the pipeline, allowing simultaneous acquisition of the pressure status of the pipeline in four directions. The control unit 4 compares and analyzes the pressure data from the four directions to determine whether the pipeline has experienced eccentricity or cross-sectional deformation.

[0066] Please see Figure 5The second guide unit 33 is located between the first guide unit 32 and the third guide unit 34, and includes four second connectors 331, four second guide rollers 332, and four drive units 333. The four second connectors 331 are correspondingly arranged with the four housings 31. One end of each second connector 331 is connected to a drive unit 333, and the other end is rotatably connected to the corresponding second guide roller 332. Each drive unit 333 is fixed to the housing 31 and is used to drive the corresponding second connector 331 to extend or retract radially along the guide hole 23. All four drive units 333 are communicatively connected to the control unit 4. The drive unit 333 is an electric push rod, the cylinder of which is fixed to the inner wall of the housing 31. The extension / retraction end of the electric push rod is connected to the second connector 331. After the control unit 4 sends an extension or retraction command to the electric push rod, the electric push rod drives the second connector 331 to extend or retract radially along the guide hole 23, causing the second guide rollers 332 to move closer to or further away from the tube center. When the heat exchange tube 5 is not centered in the guide hole 23, the control unit 4 determines the offset orientation based on the pressure data collected by the sensor 343 in the third guide unit 34. Then, it controls the corresponding drive component 333 to push the second connector 331 out, causing the second guide roller 332 to output thrust radially towards the tube center, pushing the offset tube wall back to the center position. This actively adjusts the pipe position during the guiding process, preventing the pipe from being eccentrically attached to the wall during lowering. After correction, the control unit 4 controls the drive component 333 to retract back to its original position, and the second guide roller 332 returns to its initial position.

[0067] The implementation principle of this embodiment is as follows: Before construction, the support frame 11 is horizontally erected above the borehole 6. According to the geothermal well diameter and the spacing of the heat exchange tubes, the fixing piece 2123 is loosened, and the connecting plate 2122 is stretched or pushed to adjust the spacing between the two sets of guide holes 23. After adjustment, the fixing piece 2123 is tightened to lock it in place.

[0068] When lowering the tube, slide the fastening piece 22 along the second mounting rod 13, and flip the flipping piece 21 upward around the first mounting rod 12. Place the heat exchange tube 5 into the first semi-circular groove 2111, then flip the flipping piece 21 back to its original position, push the fastening piece 22 to the mating position, so that the first semi-circular groove 2111 and the second semi-circular groove 221 surround to form the guide hole 23. Pass the bolt through the bolt through hole of the first mounting ear 2112 and the second mounting ear 222 and tighten the nut to lock the two together.

[0069] During the pipeline lowering process, the pipeline first passes through the uppermost third guide unit 34 located in the guide hole 23. Four sensors 343 collect the pressure values ​​of the pipeline against the four third guide rollers 342 in real time and send them to the control unit 4. The pipeline continues to descend through the middle second guide unit 33. The control unit 4 determines the pipeline's offset direction and type based on the pressure data fed back by the sensors 343, and issues an extension command to the electric push rod in the corresponding direction. The second guide roller 332 pushes radially towards the center of the pipe, pushing the offset pipe wall back to the center position. After the back pressure continues for a set time, the electric push rod retracts back to its original position, and the next round of data collection and comparison begins. The pipeline finally passes through the lowermost first guide unit 32. After the four first guide rollers 322 come into contact with the outer wall of the pipeline, they passively rotate as the pipeline moves downward, converting sliding friction into rolling friction and reducing the wear of the outer wall of the pipeline when it enters the orifice.

[0070] The downward pressure and lateral swaying force generated during the pipe lowering process are transmitted circumferentially through the guide hole 23 to the first mounting ear 2112 and the second mounting ear 222, and then through the slot 24 to the two second mounting rods 13, which are borne by the support frame 11 as a whole. After the pipe is lowered, the nuts are removed and the bolts are taken out. The fastening piece 22 is slid open along the second mounting rod 13, and the flipping piece 21 is flipped open, so that the construction device can be removed from the pipe.

[0071] Example 2

[0072] Please see Figure 6 The construction method of the ground source heat exchange pipe 5 provided in this application embodiment adopts the construction device in embodiment 1 and includes the following steps:

[0073] S1. Complete borehole 6 and perform reverse circulation cleaning, leaving a sediment-receiving section 63 at the bottom of the borehole. The actual final depth of borehole 6 is 1-2m greater than the design depth, with the over-drilled section serving as a sediment-receiving area. Reverse circulation cleaning involves pumping out the drilling mud from the borehole while simultaneously injecting new mud to remove residue and sediment. The cleaning airflow should be no less than 6m³ / min, the specific gravity of the circulating mud should be controlled between 1.05 and 1.10, the total cleaning time should be no less than 30 minutes, and the actual measured sediment thickness at the bottom of the borehole after completion should not exceed 5cm; if it exceeds this, the cleaning time should be extended by 10 minutes. The sediment-receiving section 63 at the bottom of the borehole provides space for the residue, preventing it from accumulating on the borehole wall of the heat exchange section and increasing contact thermal resistance. It also provides a buffer space for subsequent grouting processes, preventing voids from forming at the bottom of the borehole.

[0074] S2. A guiding device is installed at the orifice to guide and constrain the heat exchange tube 5 and lower it into the borehole 6. During the lowering process, the heat exchange tube 5 is corrected for any deviation. Specifically, the support frame 11 of the construction device is fixed at the orifice of the borehole 6 to ensure its stability. Then, the flipping part 21 is flipped open around the first mounting rod 12, and the fastening part 22 is slid open along the second mounting rod 13. The heat exchange tube 5 is placed into the first semi-circular groove 2111, and then the flipping part 21 is flipped back to its original position. The fastening part 22 is pushed to the mating position so that the first semi-circular groove 2111 and the second semi-circular groove 221 close to form the guide hole 23. The bolts between the first mounting ear 2112 and the second mounting ear 222 are tightened to lock the flipping part 21 and the fastening part 22. After the heat exchange tube 5 passes through the guide hole 23, it is slowly lowered, and the pipe centering status is checked every 50m.

[0075] The offset correction operation during the lowering process specifically includes the following steps:

[0076] S21. Set a force threshold and a back pressure preset time in the control unit 4. The force threshold is determined based on the tube material characteristics and allowable offset of the heat exchange tube 5. The back pressure preset time is the time it takes for the tube to just complete its elastic recovery under the corresponding radial force level, which is used to limit the duration of a single force application by the drive component 333; if the back pressure continues for too long, the second guide roller 332 will excessively push the tube wall from the offset side to the opposite direction to form a reverse eccentricity, or cause new local indentations in the tube wall under continuous radial compression, resulting in secondary damage to the correction itself.

[0077] S22. The pressure data applied by the heat exchange tube 5 to each third guide roller 342 is collected in real time by the four sensors 343 around each guide hole 23, and transmitted to the control unit 4 for comparison.

[0078] S23. When the pressure data collected by the sensor 343 on only one side exceeds the force threshold, the control unit 4 determines that the heat exchange tube 5 has eccentrically bent, that is, the pipe is offset and bent to that side due to the residual bending stress after being unwound from the coiled state; the control unit 4 then controls the corresponding drive 333 on that side to start, driving the corresponding second guide roller 332 to extend radially towards the tube core to apply back pressure, pushing the bent tube section towards the tube core, and correcting the bend of the heat exchange tube 5.

[0079] S24. When the back pressure continues to reach the preset back pressure time, the control unit 4 controls the corresponding drive component 333 to reset and retract, the second guide roller 332 retracts to the initial position, and the control unit 4 re-enters the pressure data acquisition and comparison, waiting for the next judgment cycle.

[0080] In this application, when the pressure data collected simultaneously by two relatively distributed sensors 343 exceeds the force threshold, it indicates that the pipe is not deflected on one side, but is simultaneously compressed in two opposite directions, and the pipe cross-section is compressed into an elliptical shape. The control unit 4 determines that the heat exchange tube 5 has undergone cross-sectional deformation, and then controls two drive units 333 located in the same radial direction as the two sensors 343 to start synchronously, driving the corresponding two second guide rollers 332 to simultaneously squeeze the heat exchange tube 5 towards the tube core, clamping the elliptical tube wall from opposite sides to restore it to a circular shape. After the correction continues for a preset back pressure time, the two drive units 333 synchronously reset and retract, and the control unit 4 re-enters the pressure data acquisition and comparison.

[0081] When the pressure data collected by three sensors 343 simultaneously exceeds the force threshold, while the pressure data collected by the remaining sensor 343 does not exceed the force threshold, it indicates that the pipeline has shifted and bent in the direction that does not exceed the threshold, and the cross-section has also deformed. The control unit 4 identifies the sensor with the largest pressure value among the three sensors 343 that exceed the threshold, determines that this direction is the main direction of the bend and protrusion, and first controls the drive unit 333 in this direction to start, pushing the pipeline back from the protruding side to the central area; after the back pressure preset time is reached, the drive unit 333 resets, and the control unit 4 re-collects pressure data; if the pressure data on both sides still exceed the force threshold at this time, the corresponding two drive units 333 are controlled to start synchronously for secondary correction according to the cross-section deformation method, and after the back pressure preset time is reached, they are reset and retreated, and the data collection and comparison are entered again.

[0082] S3. The borehole wall is divided from bottom to top into a deep heat exchange section 62 and a shallow insulation section 61. The boundary depth between these two sections can be adjusted according to local climate and geological conditions, preferably located at a depth within the constant temperature zone of the formation. The deep heat exchange section 62 is located in a year-round constant temperature stratum and is the main heat exchange zone of the system, used for heat exchange with the soil. The shallow insulation section 61 is most affected by seasonal temperature fluctuations and is the largest heat loss channel in the entire well, used to reduce heat loss and serve as insulation.

[0083] S4. Inject a pre-set dose of silicon-based interface activator from bottom to top within the deep heat exchange section 62, simultaneously coordinating with air lift agitation for borehole cleaning. The silicon-based interface activator is a low-viscosity silicon-based penetrating activator, mainly composed of water-soluble silicate compound surfactants. It utilizes the penetrating and dispersing effect of silicates and the wetting and stripping effect of surfactants to achieve mud skin stripping and interface activation. The activator dosage per unit well section in the deep heat exchange section 62 is 1.2–1.5 L / m, and sufficient activator is simultaneously added to the bottom sediment receiving section 63. Using an injection device, the silicon-based interface activator is injected upwards from the lower part of the deep heat exchange section 62, while simultaneously using an air lift device to inject gas into the borehole to create agitation. Continuous soaking for at least 15 minutes forces the stripping of the intact mud skin from the borehole wall, exposing the original heat exchange fractures in the soil and rock, reducing the thermal resistance at the pipe-soil interface, and enhancing the heat exchange effect. After activation, the expected reduction in the thermal resistance at the pipe-soil interface is no less than 40%.

[0084] S5. Inject a silicon-based interface activator at a lower than preset dosage into the shallow insulation section 61 and allow it to soak without mechanical disturbance. The activator dosage per unit well section of the shallow insulation section 61 is 0.3–0.5 L / m, which is one-quarter of the dosage used in the deep heat exchange section 62. The injection should be carried out slowly. After injection, allow it to soak for 5 minutes without mechanical disturbance, removing only the surface mud and preserving the original fine mud-like insulation layer of the formation. The interface thermal resistance reduction should be controlled within 10% to retain the insulation performance of the shallow layer and avoid over-activation that could form heat conduction channels and increase heat loss at the wellhead. After both activation stages are completed, perform a short-term cleaning of the wellbore for 3–5 minutes, using low-volume air circulation to remove slag. Do not flush the shallow insulation section 61 with high flow rate and high pressure.

[0085] S6. High thermal conductivity grout and low thermal conductivity grout shall be prepared and stored independently in a main mixing tank and an insulation grout mixing tank, respectively. The effective volume of the main mixing tank shall be not less than 8 m³, and the mixing speed shall be 60 r / min; the effective volume of the insulation grout mixing tank shall be not less than 2 m³, and the mixing speed shall be 30 r / min; the pipelines and pumps of the two mixing systems shall not be connected to each other. The high thermal conductivity grout shall be based on silicate cement, compounded with graphite and quartz sand thermally conductive fillers, with a thermal conductivity of not less than 1.8 W / (m·K), a flowability of not less than 300 mm, a 28-day compressive strength of not less than 4 MPa, and a bleeding rate of not more than 0.5%, and shall be used to fill the deep heat exchange section 62. The low thermal conductivity grout uses silicate cement as a base material, with fly ash and hollow glass microspheres as thermal insulation fillers. Its thermal conductivity does not exceed 0.45 W / (m·K), its flowability is not less than 300 mm, and its 28-day compressive strength is not less than 4 MPa. It is used to fill shallow insulation sections 61. The prepared grout is stored separately in corresponding mixing tanks to avoid premature mixing and ineffectiveness.

[0086] S7. Start a grouting pump to extract high thermal conductivity grout and pump it at the first grouting pressure, simultaneously filling the sediment receiving section 63 and the deep heat exchange section 62. Grouting should begin within 40 minutes of pipe lowering to prevent secondary mud cake formation on the borehole wall. Lower the grouting pipe to a position 0.3–0.5 m from the bottom of the borehole. Use a horizontal positive displacement grouting pump with a rated flow rate of 8–12 L / min. Turn on the grouting pump to extract the high thermal conductivity grout from the main mixing tank and deliver it into the borehole at the first grouting pressure, filling the sediment receiving section 63 and the deep heat exchange section 62. Raise the grouting pipe upwards from the bottom of the borehole at a uniform speed of 0.8–1.2 m / min. The first grouting pressure is set in stages according to the burial depth: 0.4–0.5 MPa for 200–300 m, 0.3–0.4 MPa for 100–200 m, and 0.2–0.3 MPa for 20–100 m. If the pressure drops suddenly during grouting, the lifting process should be paused and the pressure stabilized for 3 minutes before grouting continues. If the pressure continues to exceed 0.6 MPa, the pipe should be lifted slowly to prevent blockage. The pressure should be stabilized for 1 minute every 10 meters of lifting, and the overall porosity after grouting should not exceed 5%. The grouting process should be uninterrupted, and the duration of a single stop should not exceed 2 minutes.

[0087] S8. When the grouting reaches the boundary between the deep heat exchange section 62 and the shallow insulation section 61, the suction end of the grouting pump is switched to the insulation grout mixing tank to extract low thermal conductivity grout without stopping the pump. When the grouting height reaches this boundary, the suction end is transferred from the main mixing tank to the insulation grout mixing tank without stopping the pump. The transfer time should not exceed 90 seconds. The switching can be completed by simply cleaning the suction pipe opening, without disassembling or cleaning the grouting pump and delivery pipeline. Switching without stopping the pump can avoid the presence of faults at the boundary, ensure the continuity and compactness of the filling, and eliminate the need for pump shutdown and pipe cleaning.

[0088] S9. Control the grouting pump to continuously pump low thermal conductivity grout at a second grouting pressure lower than the first grouting pressure until the shallow insulation section 61 is completely filled. The second grouting pressure is 0.15-0.25 MPa, and the grouting flow rate is reduced to 5-7 L / min. Continue pumping low thermal conductivity grout to fill the shallow insulation section 61. The lower second grouting pressure can avoid destroying the hole wall interface formed by the shallow and mildly activated grout. When pure insulation grout is continuously and uniformly returned from the borehole opening without mud or water, maintain the pressure for 2 minutes and then stop the pump. After grouting, allow it to settle for 60 minutes, remove the laitance from the borehole opening, and backfill the borehole opening with graded sand and gravel and undisturbed soil in layers. Each layer should be compacted to a thickness of 20 cm and a compaction degree of not less than 93%, thus isolating the heat exchange channel between the external air and the shallow strata from the surface. After the grouting of a single well is completed, move the suction pipe back to the main mixing tank. Grouting operations for the next well can be carried out without cleaning the grouting system.

[0089] The implementation principle of this embodiment is as follows: During construction, borehole 6 is first drilled according to S1 and the borehole is cleaned by reverse circulation. The sediment receiving section 63 at the bottom of the borehole is used to collect the sediment remaining after cleaning, so that it does not adhere to the borehole wall of the heat exchange section. According to S2, the construction device of embodiment 1 is set at the borehole opening to guide and constrain the heat exchange tube 5. After the heat exchange tube 5 passes through the guide hole 23, it is slowly lowered. During the lowering process, the control unit 4 continuously performs correction operations: four sensors 343 continuously collect the radial pressure of the pipeline on the third guide roller 342 and transmit it to the control unit 4. The control unit 4 compares the pressure values ​​in each direction with the preset force threshold. If only one side of the pressure exceeds the threshold, the control unit 4 determines that the pipeline has eccentrically bent and controls the electric push rod on that side to push out the second guide roller 332 to apply counter pressure. If the pressure on both sides exceeds the threshold at the same time, the control unit 4 determines that the pipeline has undergone cross-sectional deformation and controls the electric push rods on both sides to simultaneously push out the second guide roller 332 to clamp the pipe wall from both sides to restore it to a circular shape. After the counter pressure reaches the preset time, the drive unit 333 resets and re-enters the next round of collection and comparison. This cycle continues until the pipeline is lowered into place.

[0090] After the pipeline is in place, the borehole wall is divided into a deep heat exchange section 62 and a shallow insulation section 61 according to S3. According to S4, a preset dose of silicon-based interface activator is injected from bottom to top into the deep heat exchange section 62. Simultaneously, gas is injected into the borehole through an air-lift device to create disturbance. Under the agitation of the airflow, the activator fully contacts and peels off the mud cake on the borehole wall, reducing the thermal resistance of the pipe-soil interface in this section. According to S5, a lower dose of activator is injected into the shallow insulation section 61. After injection, no mechanical disturbance is applied; the section is left to soak, allowing the activator to only mildly treat the borehole wall surface, preserving the insulation properties of this section and preventing the formation of thermally conductive channels in the shallow layer due to over-activation. According to S6, high thermal conductivity grouting material and low thermal conductivity grouting material are prepared separately in the main mixing tank and the insulation grout mixing tank. The two types of grouting materials are stored separately and not mixed. Start the grouting pump according to S7, connect the suction end to the main mixing tank, and extract the high thermal conductivity grouting material with the first grouting pressure. Pump it upward from the bottom of the hole to fill the sediment receiving section 63 and the deep heat exchange section 62 in sequence.

[0091] According to S8, when the grout level rises to the boundary between the deep heat exchange section 62 and the shallow insulation section 61, the suction end is switched from the main mixing tank to the insulation grout mixing tank without stopping the grouting pump. This allows the pumped grout to continuously transition from high thermal conductivity grout to low thermal conductivity grout without interruption at the boundary, preventing voids or discontinuities between the two types of grout. According to S9, the grouting pressure is reduced from the first grouting pressure to the second grouting pressure. The low thermal conductivity grout is pumped at a lower pressure to fill the shallow insulation section 61 until the borehole opening. The lower pumping pressure avoids damaging the shallow, mildly activated borehole wall interface.

[0092] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Any other corresponding changes and modifications made based on the technical concept of this application should be included within the scope of protection of this application.

Claims

1. A construction method for a ground source heat exchanger pipe, characterized in that, Includes the following steps: S1. Complete drilling (6) and perform reverse circulation cleaning, leaving a sediment-containing section (63) at the bottom of the hole; S2. A guide device is set at the orifice to guide and constrain the heat exchange tube (5) and lower it into the borehole (6). During the lowering process, the heat exchange tube (5) is offset and corrected. S3. Divide the borehole wall from bottom to top into a deep heat exchange section (62) and a shallow insulation section (61); S4. A preset dose of silicon-based interface activator is injected from bottom to top into the deep heat exchange section (62), and the hole is cleaned simultaneously with air lift disturbance; S5. Inject the silicon-based interface activator at a dose lower than the preset amount into the shallow insulation section (61) and let it stand and soak without mechanical disturbance; S6. High thermal conductivity grout and low thermal conductivity grout are prepared and stored independently in a main mixing tank and an insulation grout mixing tank, respectively; S7. Start a grouting pump, extract the high thermal conductivity grout and pump it at the first grouting pressure to simultaneously fill the sediment receiving section (63) and the deep heat exchange section (62); S8. When the grouting is raised to the boundary between the deep heat exchange section (62) and the shallow heat insulation section (61), the suction end of the grouting pump is switched to the heat insulation grout mixing tank without stopping the pump, and the low thermal conductivity grouting material is extracted. S9. Control the grouting pump to continuously pump the low thermal conductivity grout at a second grouting pressure lower than the first grouting pressure until the shallow insulation section (61) is completely filled.

2. The construction method of the ground source heat exchange pipe according to claim 1, characterized in that, In step S7, the first grouting pressure is set in segments according to the burial depth of the borehole (6), and the grouting pipe is lifted upward at a constant speed from the bottom of the hole; when the pressure suddenly drops during the grouting process, the lifting is paused and the pressure is stabilized and grout is added; when the pressure continues to exceed the preset upper limit pressure, the grouting pipe is slowly lifted; and the pressure is stabilized for a preset time after each preset height is lifted.

3. The construction method of the ground source heat exchange pipe according to claim 1, characterized in that, Step S9 is followed by the following steps: S10. After grouting is completed, allow the soil to settle for a preset time, remove the laitance at the borehole opening, and backfill the borehole opening with graded sand and gravel and undisturbed soil in layers to isolate the heat exchange channel between the surface air and the shallow strata.

4. A construction device for a ground source heat exchanger pipe, applicable to the construction method according to any one of claims 1 to 3, characterized in that, include: The support mechanism (1) includes a support frame (11), two first mounting rods (12) and two second mounting rods (13). The two first mounting rods (12) are arranged parallel to each other and are fixed to the support frame (11). The two second mounting rods (13) are arranged parallel to each other and are fixed to the support frame (11). The first mounting rods (12) are perpendicular to the second mounting rods (13). Two sets of guiding mechanisms (2) are provided, each set of guiding mechanisms (2) is corresponding to one of the two first mounting rods (12). Each set of guiding mechanisms (2) includes a flipping part (21) and a fastening part (22). The flipping part (21) is rotatably connected to the corresponding first mounting rod (12). The flipping part (21) is provided with two first semicircular grooves (2111). The two ends of the fastening part (22) are slidably connected to the two second mounting rods (13) respectively. The fastening part (22) is provided with two second semicircular grooves (221) corresponding to the two first semicircular grooves (2111) respectively. Each first semicircular groove (2111) and the corresponding second semicircular groove (221) together form a guide hole (23) for the heat exchange tube (5) to pass through. The flipping part (21) and the fastening part (22) are detachably connected.

5. The construction device for the ground source heat exchanger pipe according to claim 4, characterized in that, The flipping component (21) includes a guide portion (211) and a flipping portion (212). Two first semi-circular grooves (2111) are formed in the guide portion (211). The flipping portion (212) includes a sliding plate (2121), a connecting plate (2122), and a fixing member (2123). The sliding plate (2121) is rotatably connected to the first mounting rod (12). The connecting plate (2122) is slidably engaged with the sliding plate (2121). The guide portion (211) is fixed to the connecting plate (2122). The fixing member (2123) is used to limit and fix the connecting plate (2122) to the sliding plate (2121).

6. The construction device for the ground source heat exchanger pipe according to claim 5, characterized in that, The guide portion (211) has a first mounting ear (2112) at each end, and the fastener (22) has a second mounting ear (222) at each end. The first mounting ear (2112) and the second mounting ear (222) are detachably connected. The first mounting ear (2112) and the second mounting ear (222) are both provided with a slot (24), and are slidably connected to the two second mounting rods (13) through the corresponding slot (24).

7. The construction device for the ground source heat exchanger pipe according to claim 4, characterized in that, Each set of guide mechanisms (2) further includes two adjustment components (3), which are respectively arranged in correspondence with the two guide holes (23); each adjustment component (3) includes four housings (31), and a first guide unit (32), a second guide unit (33) and a third guide unit (34) arranged sequentially from bottom to top along the axial direction of the guide hole (23); the four housings (31) are arranged in a circular array around the axis of the corresponding guide hole (23), and two of the housings (31) are fixed to the outer wall of the corresponding first semicircular groove (2111), and the other two housings (31) are fixed to the outer wall of the corresponding second semicircular groove (221).

8. The construction device for the ground source heat exchanger pipe according to claim 7, characterized in that, The first guide unit (32) includes four first connectors (321) and four first guide rollers (322). The four first connectors (321) are arranged in a one-to-one correspondence with the four housings (31). One end of each first connector (321) is fixed to the bottom of the corresponding housing (31), and the other end is rotatably connected to the corresponding first guide roller (322).

9. The construction device for the ground source heat exchanger pipe according to claim 7, characterized in that, The construction device also includes a control unit (4), and the third guide unit (34) includes four third connectors (341), four third guide rollers (342), and four sensors (343); the four third connectors (341) are arranged one-to-one with the four housings (31); each third connector (341) includes a connecting section (3411) and a pressure-sensing section (3412), the connecting section (3411) is fixed to the inner wall of the corresponding housing (31), the pressure-sensing section (3412) is rotatably connected to the corresponding third guide roller (342), and the pressure-sensing part of the sensor (343) is sandwiched between the connecting section (3411) and the pressure-sensing section (3412); all four sensors (343) are communicatively connected to the control unit (4).

10. The construction device for the ground source heat exchanger pipe according to claim 9, characterized in that, The second guide unit (33) includes four second connectors (331), four second guide rollers (332), and four drive members (333). The four second connectors (331) are arranged one-to-one with the four housings (31). One end of each second connector (331) is connected to the drive member (333), and the other end is rotatably connected to the corresponding second guide roller (332). Each drive member (333) is fixed to the housing (31) and is used to drive the corresponding second connector (331) to extend and retract radially along the guide hole (23). All four drive members (333) are communicatively connected to the control unit (4).

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