A process for vertical buried pipe laying auxiliary technology for shallow geothermal energy in karst areas

Abstract

This invention discloses an auxiliary process for laying vertical buried pipes for shallow geothermal energy in karst areas, belonging to the field of vertical buried pipe technology. The process includes the following steps: detecting the distribution of karst caves in the vertical direction of the heat exchange hole, planning the grouting location of the karst caves, and the distribution of rammed earth and grouting layers in the heat exchange hole; lowering a U-shaped pipe through a ramming hammer, with the U-shaped pipe bend fixedly installed on an anchoring precast plate, to the bottom of the heat exchange hole; lowering the ramming hammer to the designed height of the first grouting layer, and starting grouting into the heat exchange hole; raising the ramming hammer to the designed height of the first rammed earth layer, releasing soil into the heat exchange hole, and repeatedly raising and lowering the ramming hammer to compact the soil; raising the ramming hammer to the designed height of the second grouting layer, and starting grouting into the heat exchange hole. This invention uses grouting layers to block karst caves in the heat exchange hole in karst areas, and the alternating distribution of grouting and rammed earth layers improves the heat exchange efficiency of the U-shaped pipe.

Description

Technical Field

[0001] This invention belongs to the field of vertical buried pipe technology, and particularly relates to an auxiliary process for laying vertical buried pipes for shallow geothermal energy in karst areas. Background Technology

[0002] A ground source heat pump is a highly efficient and energy-saving system that utilizes shallow geothermal resources (also known as geothermal energy, including the energy from surface water, soil, and groundwater) to provide both heating and cooling. The ground source heat pump achieves heat exchange between the system and the earth through the flow of a circulating fluid (water or antifreeze with water as the main component) in closed underground buried pipes. Currently, ground source heat pump systems utilize vertical buried pipes to exchange geothermal energy with the soil through a heat transfer medium. The vertical buried pipe heat exchanger is the carrier of the ground source heat pump system and serves as the energy source for central air conditioning. The buried vertical pipe heat exchanger is typically a high-strength, flexible single-U or double-U shaped PE pipe with an outer diameter of 25–32 mm, generally 10–200 m in length, used to absorb heat or cold from the soil to supply building heating or cooling.

[0003] However, during construction, the geological conditions vary from region to region, leading to different levels of technical difficulty in constructing ground source heat pump systems. In particular, karst areas have complex geological structures, and the heat exchange holes may contain karst caves, which can easily result in poor thermal conductivity of the U-shaped tubes. Summary of the Invention

[0004] In view of this, the present invention provides an auxiliary process for vertical buried pipe laying for shallow geothermal energy in karst areas, which involves grouting and sealing the karst caves, with the grouting layer and the rammed earth layer being distributed alternately, thereby improving the heat exchange efficiency of the U-shaped pipe.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A process for assisting in the installation of vertical buried pipes for shallow geothermal energy in karst areas includes the following steps:

[0007] S1. Detect the distribution of karst caves in the vertical direction of the heat exchange holes, plan the grouting location of the karst caves, and the distribution of rammed earth layers and grouting layers in the heat exchange holes;

[0008] S2. The U-shaped pipe passes through the ramming hammer, and the U-shaped pipe elbow is fixedly installed on the anchored precast plate before being lowered to the bottom of the heat exchange hole;

[0009] S3. After lowering the ramming hammer to the designed height of the first grouting layer, start grouting into the heat exchange holes;

[0010] S4. Raise the ramming hammer to the designed height of the first rammed soil layer, release soil into the heat exchange hole, and repeatedly raise the ramming hammer to compact the soil.

[0011] S5. Raise the ramming hammer to the designed height of the second grouting layer and begin grouting into the heat exchange holes.

[0012] Further, repeat steps S4-S5 until the wellhead of the heat exchange hole.

[0013] Furthermore, in step S2, after the U-shaped pipe passes through the ramming hammer, a U-shaped pipe clamp is installed on the U-shaped pipe every time it is lowered a certain distance.

[0014] Furthermore, in steps S3 and S5, the steel wire pulling the ramming hammer at the wellhead is observed. When the tension of the steel wire decreases, the karst cave is filled, the concrete slurry begins to lift the ramming hammer upwards, and the grouting stops.

[0015] Furthermore, the ramming hammer is equipped with lifting lugs and a U-shaped tube through hole.

[0016] Furthermore, the U-shaped pipe clamp is provided with a guide portion.

[0017] The beneficial effects of this invention are as follows: the anchor precast plate is fixedly connected to the U-shaped tube elbow, and the U-shaped tube is sunk to the bottom of the heat exchange hole, so that the U-shaped tube is straightened in the heat exchange hole and does not bend. At the same time, it avoids the situation where the U-shaped tube and U-shaped tube elbow are rubbed by the well wall during the traditional tube sinking technology. Grouting is injected into the heat exchange hole to block the karst cave, and then the soil is released and compacted. The grouting layer and the rammed soil layer are distributed alternately, which increases the contact area between the rammed soil layer and the U-shaped tube and improves the heat exchange efficiency. The U-shaped clamp prevents the two tubes in the U-shaped tube from contacting each other and avoids "thermal short circuit". Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of an auxiliary process for vertical buried pipe laying in shallow geothermal energy in karst areas.

[0020] Figure 2 This is a schematic diagram showing the completion of vertical buried pipe installation for shallow geothermal energy in karst areas.

[0021] Figure 3 This is a schematic diagram of the structure of a rammed earth hammer.

[0022] Figure 4 This is a structural diagram of a U-shaped pipe clamp.

[0023] In the figure:

[0024] 10-Heat exchange hole, 20-U-shaped pipe, 21-U-shaped pipe elbow, 22-U-shaped pipe clamp, 221-Guide part, 30-Anchoring precast slab, 40-First grouting layer, 50-First rammed earth layer, 60-Second grouting layer, 70-Steel wire, 80-Steel wire roller, 90-U-shaped pipe roller, 100-Ramming hammer, 101-Lifting lug, 102-U-shaped pipe through hole. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] See attached document Figure 1-4 As shown, the present invention provides an auxiliary process for laying vertical buried pipes for shallow geothermal energy in karst areas, comprising the following steps:

[0027] S1. Detect the distribution of karst caves in the vertical direction of the heat exchange hole 10, plan the grouting position of the karst caves, and the distribution of the rammed earth layer and grouting layer in the heat exchange hole 10. Grout at the depth of the karst caves and place clay with good thermal conductivity at non-karst cave locations to maximize the contact area between the rammed earth layer and the U-shaped tube 20 and improve the heat exchange efficiency of the U-shaped tube 20.

[0028] S2. The ramming hammer 100 is equipped with a lifting lug 101 and a U-shaped tube through hole 102. Initially, the steel wires 70 on the steel wire rollers 80 on both sides of the heat exchange hole 10 are connected to the lifting lug 101. The ramming hammer 100 is hoisted to the wellhead position of the heat exchange hole 10. The U-shaped tube 20 is passed through the U-shaped tube through hole 102 on the ramming hammer 100. Then, the U-shaped tube elbow 21 is fixedly installed on the anchoring precast plate 30. The worker rotates the steel wire roller 80 to lower the anchoring precast plate 30, along with the U-shaped tube elbow 21, to the bottom of the heat exchange hole 10. The U-shaped tube 20 continuously rotates out from the U-shaped tube roller 90 and extends into the heat exchange hole 10. Because the U-shaped tube 20 is mostly made of PE pipe, it is easy to get stuck during the lowering process in the heat exchange hole 10. The weight of the anchoring precast plate 30 itself allows the U-shaped tube 20 to descend all the way to the bottom of the well, facilitating the lowering process of the U-shaped tube 20. It should be noted that as the U-shaped pipe 20 passes through the ramming hammer 100 and begins to descend into the heat exchange hole 10, a U-shaped pipe clamp 22 is installed on the U-shaped pipe 20 at the wellhead of the heat exchange hole 10 every certain distance. This prevents the two pipes on the U-shaped pipe 20 from experiencing a "thermal short circuit" after being encased by the grouting layer and the rammed earth layer. The U-shaped pipe clamp 22 is equipped with a guide part 221, allowing the worker to easily clamp the U-shaped pipe 20 onto the U-shaped pipe clamp 22 at the wellhead of the heat exchange hole 10.

[0029] S3. After lowering the rammed earth hammer 100 to the designed height of the first grouting layer 40, start grouting into the heat exchange hole 10; after grouting for a certain period of time, observe the steel wire 70 pulling the rammed earth hammer 100 at the wellhead, or the worker pulls the steel wire 70 at the wellhead of the heat exchange hole 10. When the tension of the steel wire 70 decreases, the karst cave is filled, the concrete slurry begins to lift the rammed earth hammer 100 upwards, and the grouting stops.

[0030] S4. Raise the ramming hammer 100 to the designed height of the first rammed soil layer 50 and release clay into the heat exchange hole 10. The diameter of the ramming hammer 100 is smaller than the diameter of the heat exchange hole 10, and there is a U-shaped tube passing through the hole 102 in the middle. The ramming hammer 100 will not affect the downward release of clay. Workers can also repeatedly pull the steel wire 70 at the opening of the heat exchange hole 10, or vibrate the taut steel wire 70 to make the clay fall. After a certain volume of clay is released, workers can either directly and repeatedly pull the steel wire 70, or pull the steel wire 70 through the steel wire 70 tube, so that the ramming hammer 100 can repeatedly compact the soil.

[0031] S5. Raise the ramming hammer 100 to the designed height of the second grouting layer 60 and start grouting into the heat exchange hole 10; after grouting for a certain period of time, observe the steel wire 70 pulling the ramming hammer 100 at the wellhead, or the worker pulls the steel wire 70 at the wellhead of the heat exchange hole 10. When the tension of the steel wire 70 decreases, the karst cave is filled, the concrete slurry begins to lift the ramming hammer 100 upwards, and the grouting stops.

[0032] S6. Repeat steps S4-S5 until the wellhead of heat exchange hole 10 is reached, completing the installation of U-shaped pipe 20 in heat exchange hole 10 in karst areas.

[0033] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0034] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vertical ground heat exchanger pipe-laying auxiliary process for shallow geothermal energy in karst areas, characterized in that, Includes the following steps: S1. Detect the distribution of multi-layered, intermittent karst caves in the vertical direction of the heat exchange holes, plan the grouting location of the karst caves, and the distribution of alternating rammed earth layers and grouting layers in the heat exchange holes; S2. The U-shaped pipe passes through the ramming hammer, and the U-shaped pipe elbow is fixedly installed on the anchored precast plate before being lowered to the bottom of the heat exchange hole; S3. After lowering the ramming hammer to the designed height of the first grouting layer, start grouting into the heat exchange holes; S4. Raise the ramming hammer to the designed height of the first rammed soil layer, release soil into the heat exchange hole, and repeatedly raise the ramming hammer to compact the soil. S5. Raise the rammed earth hammer to the designed height of the second grouting layer and begin grouting into the heat exchange holes; thus forming a backfill structure in the heat exchange holes consisting of alternating grouting and rammed earth layers.

2. The auxiliary process for vertical buried pipe laying in shallow geothermal energy in karst areas according to claim 1, characterized in that, Repeat steps S4-S5 until the wellhead of the heat exchange hole is reached.

3. The auxiliary process for vertical buried pipe laying in shallow geothermal energy in karst areas according to claim 1, characterized in that, In step S2, after the U-shaped pipe passes through the ramming hammer, a U-shaped pipe clamp is installed on the U-shaped pipe every time it is lowered a certain distance.

4. The auxiliary process for vertical buried pipe laying in shallow geothermal energy in karst areas according to claim 1, characterized in that, In steps S3 and S5, observe the steel wire pulling the ramming hammer at the wellhead. When the tension of the steel wire decreases, the karst cave is filled, and the concrete slurry begins to lift the ramming hammer upwards, at which point the grouting stops.

5. The auxiliary process for vertical buried pipe laying in shallow geothermal energy in karst areas according to claim 1, characterized in that, The ramming hammer is equipped with lifting lugs and a U-shaped tube through hole.

6. The auxiliary process for vertical buried pipe laying in shallow geothermal energy in karst areas according to claim 3, characterized in that, The U-shaped pipe clamp is provided with a guide part.

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