Construction method of vertical buried pipe heat exchange pipe well as well point dewatering well in construction

Abstract

The application discloses a construction method of taking a vertical buried pipe heat exchange pipe well as a well point dewatering well in construction, comprising a well body, wherein the well body comprises a large-diameter section, a transition section and a small-diameter section from top to bottom in sequence; the depth of the large-diameter section and the transition section is matched with the well point dewatering pipe; the construction steps are as follows: 1, drilling downwards from the ground surface to form the well body; 2, setting a heat conducting pipe with a U-shaped lower end in the well body; 3, filling mixed material into the well body to fill the small-diameter section; 4, setting the well point dewatering pipe in the well body; 5, filling medium sand into the well body to a depth of 1m from the ground surface; 6, filling cohesive soil into the well body in the range from the medium sand to the ground surface; 7, before excavating the foundation pit, implementing dewatering work through the well point dewatering pipe arranged in the well body and corresponding well point dewatering equipment to reduce the underground water level height. The application takes the ground surface shallow section of the vertical buried pipe well as the well point dewatering well during the foundation pit excavation, realizes one well with two uses and realizes the functions of two kinds of wells.

Description

Technical Field

[0001] This invention relates to the field of technology, and in particular to a construction method for using vertical buried pipe heat exchange wells as wellpoint dewatering wells during construction. Background Technology

[0002] Vertical buried pipe heat exchange systems are a widely used type of ground source heat pump system. A common practice involves placing vertical buried pipes filled with a heat-conducting liquid into pre-drilled wells, allowing the liquid to fully exchange heat with the deep underground soil and rock. In summer, heat is transferred from the building to the soil layer, and in winter, heat is extracted from the soil. It is generally believed that the soil and rock within 20m of the ground surface are significantly affected by the atmosphere and have highly unstable temperatures. Therefore, the wells for vertical buried pipe heat exchange systems need to be drilled to a depth of 30–100m below the surface to ensure effective geothermal exchange (typically 100m). To facilitate the placement of the heat-conducting pipes, the well diameter is usually greater than 110mm. To improve the heat exchange efficiency and the thermal balance of the soil, the horizontal spacing between wells is typically set at 3–6m. The number of wells is determined by the building's heat exchange volume, and they are generally arranged in rows on a plane, ensuring consistent spacing between wells. In terms of cost, the drilling and hole-forming process is the main construction cost of vertical buried pipe heat exchange systems.

[0003] Wellpoint dewatering, as a mature foundation pit dewatering technology, is widely used in the excavation of foundation pits at depths of one or two levels. Wellpoint dewatering involves inserting several wellpoint pipes into a pre-drilled group of dewatering wells. A surface pump connected to the main dewatering pipe extracts groundwater from the area covered by the well group, thereby lowering the groundwater level in and around the foundation pit to the required elevation. Wellpoint dewatering wells are typically arranged in rows at equal intervals; the well depth is determined by the dewatering height, and based on the characteristics of wellpoint dewatering, the well depth is usually within 12 meters below the ground surface; the borehole diameter of the wells is determined according to construction conditions, generally ranging from 150 to 300 mm. Wellpoint dewatering wells are an essential temporary structure in the foundation pit excavation process. Similar to the vertical buried pipe heat exchange system, the construction cost of the wellpoint dewatering system is mainly concentrated in the drilling process.

[0004] Under traditional working conditions, vertical buried pipe wells and wellpoint dewatering wells operate independently and are not used in combination. In terms of design, since both processes require wellpoints to be arranged at a certain density, and the importance of vertical buried pipe wells as permanent facilities is clearly greater than that of wellpoint dewatering wells as temporary facilities, the design of dewatering well locations must consider avoiding the locations of vertical buried pipe wells, which to some extent increases the difficulty of foundation pit dewatering design.

[0005] In terms of construction, the simultaneous existence of the two types of wells means that the construction work surfaces of the dewatering wells and the buried pipe wells also affect and restrict each other, which brings significant inconvenience to the construction work of the two types of wells.

[0006] In terms of economics, the construction cost of both types of wells includes the construction cost of drilling, which increases the overall construction cost.

[0007] Furthermore, the dewatering wells were abandoned after the foundation pit was backfilled, resulting in unnecessary waste.

[0008] Therefore, the two types of wells can be combined into one, with permanent and temporary features, without affecting each other's work efficiency. This effectively avoids various problems in design, construction, and economy, which is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0009] In view of the above-mentioned defects of the prior art, the present invention provides a construction method for using vertical buried pipe heat exchange wells as wellpoint dewatering wells during construction. The purpose is to use the upper shallow section of the vertical buried pipe well as a wellpoint dewatering well, thereby combining the two types of wells into one, which can reduce the construction cost of wellpoint dewatering wells and the construction land area.

[0010] To achieve the above objectives, this invention discloses a construction method for using vertical buried heat exchange pipe wells as wellpoint dewatering wells during construction, including a well body, wherein the well body is vertically arranged and includes, from top to bottom, a large-diameter section, a transition section and a small-diameter section.

[0011] The inner diameter of the large-diameter section is larger than that of the small-diameter section, the upper end is located on the ground surface, and the lower end is connected to the transition section;

[0012] The transition section is a cone shape with the top removed. The inner diameter of the upper end matches the large diameter section, and the inner diameter of the lower end matches the small diameter section and is connected to the small diameter section.

[0013] The depths of the large-diameter section and the transition section are matched with those of the wellpoint dewatering pipe;

[0014] The depth from the ground surface to the bottom of the small-diameter section matches the heat pipe;

[0015] The specific construction steps are as follows:

[0016] Step 1: Drill a hole downwards from the surface to form the well body;

[0017] Step 2: Install the heat-conducting pipe with a U-shaped lower end inside the well body; the lower end of the heat-conducting pipe is located near the bottom of the small-diameter section;

[0018] Step 3: Fill the well body with a mixture; the filling height of the mixture is such that it fills the small diameter section;

[0019] Step 4: Install the wellpoint dewatering pipe inside the well body; the lower end of the wellpoint dewatering pipe is located within the transition section, near the junction of the transition section and the small-diameter section;

[0020] Step 5: Fill the well body with medium sand; the medium sand is filled to a depth of 1 meter from the ground surface;

[0021] Step 6: The area from the medium sand to the surface within the well body is filled with cohesive soil;

[0022] Step 7: Before excavating the foundation pit, dewatering is carried out by installing the wellpoint dewatering pipes and corresponding wellpoint dewatering equipment in the well body to lower the groundwater level.

[0023] Preferably, after the precipitation work is completed, the following steps are performed:

[0024] Step 8: Pull out the wellpoint dewatering pipe and dismantle the corresponding wellpoint dewatering equipment;

[0025] Step 9: Fill the gap created by pulling out the well point dewatering pipe inside the well body with cement grout.

[0026] Step 10: After all construction is completed, connect the heat pipe to the HVAC equipment. The heat transfer fluid in the heat pipe circulates within the heat pipe to achieve ground source heat exchange.

[0027] Preferably, the mixture comprises sand and bentonite.

[0028] The beneficial effects of this invention are:

[0029] This invention utilizes the shallow surface section of a vertical buried well as a wellpoint dewatering well during foundation pit excavation, achieving dual-purpose functionality with a single well drilling operation.

[0030] The method of this invention enables the drilled well to be used as a dewatering well for the foundation pit during the early construction period, and to become a heat transfer working well for the ground source heat pump system during the later building use period.

[0031] The method of this invention allows the location of the vertical buried pipe well and the wellpoint dewatering well to coincide, realizing the integration of the two wells into one. The construction of the dewatering well and the construction of the buried pipe well can be organically combined without affecting each other.

[0032] This method reduces both the construction cost of dewatering wells and the land area required for their construction.

[0033] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0034] Figure 1 This diagram illustrates the state of a well body formed after drilling in one embodiment of the present invention.

[0035] Figure 2 This diagram illustrates the state after the heat pipe is installed and the mixture is filled, according to one embodiment of the present invention.

[0036] Figure 3 This diagram illustrates the state of wellpoint dewatering pipe installation and cohesive soil filling in one embodiment of the present invention.

[0037] Figure 4 This diagram illustrates a state of dewatering via a wellpoint dewatering pipe and a wellpoint dewatering device in one embodiment of the present invention.

[0038] Figure 5 The figure shows a schematic cross-sectional view along direction AA in the present invention.

[0039] Figure 6 This diagram illustrates the state of the heat pipe in use after the wellpoint dewatering pipe and wellpoint dewatering equipment have been removed in one embodiment of the present invention. Detailed Implementation

[0040] Example

[0041] like Figures 1 to 5 As shown, the construction method of using vertical buried heat exchange pipe wells as wellpoint dewatering wells includes a well body 1, which is set vertically and includes a large diameter section 11, a transition section 12 and a small diameter section 13 from top to bottom.

[0042] The inner diameter of the large-diameter section 11 is larger than that of the small-diameter section 13. Its upper end is located on the ground surface, and its lower end is connected to the transition section 12.

[0043] The transition section 12 is a cone shape with the top removed. The inner diameter of the upper end matches that of the large diameter section 11, and the inner diameter of the lower end matches that of the small diameter section 13, and is connected to the small diameter section 13.

[0044] The depths of the large-diameter section 11 and the transition section 12 are matched with those of the wellpoint dewatering pipe 4;

[0045] The depth from the ground surface to the bottom of the small-diameter section 13 matches that of the heat pipe 2;

[0046] The specific construction steps are as follows:

[0047] Step 1: Drill a hole downwards from the surface to form well body 1;

[0048] Step 2: Install a heat pipe 2 with a U-shaped lower end inside the well body 1; the lower end of the heat pipe 2 is located near the bottom of the small diameter section 13.

[0049] Step 3: Fill the well body 1 with mixture 3; the filling height of mixture 3 is such that it fills the small diameter section 13.

[0050] Step 4: Install a wellpoint dewatering pipe 4 inside the well body 1; the lower end of the wellpoint dewatering pipe 4 is located inside the transition section 12, near the junction of the transition section 12 and the small diameter section 13.

[0051] Step 5: Fill the well body 1 with medium sand 5; fill the medium sand 5 to a depth of 1 meter from the ground surface;

[0052] Step 6: Fill the well body 1 with cohesive soil 6 from medium sand 5 to the surface.

[0053] Step 7: Before excavating the foundation pit, dewatering work is carried out by using the wellpoint dewatering pipe 4 installed in the well body 1 and the corresponding wellpoint dewatering equipment 7 to lower the groundwater level.

[0054] This invention utilizes the large-diameter section 11 and transition section 12 of the well body 1 near the ground surface as temporary wellpoint dewatering wells. After construction is completed, the well body 1 is used as a permanent vertical buried heat exchange pipe well. During construction, the two types of wells are combined into one, which can reduce the construction cost of wellpoint dewatering wells and the construction area.

[0055] like Figure 6 As shown, in some embodiments, after the precipitation work is completed, the following steps are performed:

[0056] Step 8: Pull out the wellpoint dewatering pipe 4 and remove the corresponding wellpoint dewatering equipment 7;

[0057] Step 9: Fill the gap created by pulling out the well point dewatering pipe 4 inside the well body 1 with cement grout.

[0058] Step 10: After completing all construction, connect the heat pipe 2 to the HVAC equipment. The heat transfer liquid in the heat pipe 2 circulates within the heat pipe 2 to achieve ground source heat exchange.

[0059] In some embodiments, mixture 3 comprises sand and bentonite.

[0060] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A construction method for using vertical buried heat exchange pipe wells as wellpoint dewatering wells during construction, including a well body (1); characterized in that, The well body (1) is vertically arranged and includes, from top to bottom, a large-diameter section (11), a transition section (12), and a small-diameter section (13); The inner diameter of the large-diameter section (11) is larger than that of the small-diameter section (13), the upper end is located on the ground surface, and the lower end is connected to the transition section (12); The transition section (12) is a cone with the top removed. The inner diameter of the upper end matches the large diameter section (11), and the inner diameter of the lower end matches the small diameter section (13), and is connected to the small diameter section (13). The depths of the large-diameter section (11) and the transition section (12) are matched with those of the wellpoint dewatering pipe (4); The depth from the ground surface to the bottom of the small diameter section (13) matches the heat pipe (2); The specific construction steps are as follows: Step 1: Drill a hole downward from the surface to form the well body (1); Step 2: Install the heat pipe (2) with a U-shaped lower end inside the well body (1); the lower end of the heat pipe (2) is located near the bottom of the small diameter section (13); Step 3: Fill the well body (1) with a mixture (3); the filling height of the mixture (3) is such that it fills the small diameter section (13); Step 4: Install the well point dewatering pipe (4) inside the well body (1); the lower end of the well point dewatering pipe (4) is located inside the transition section (12), near the junction of the transition section (12) and the small diameter section (13); Step 5: Fill the well body (1) with medium sand (5); the medium sand (5) is filled to a depth of 1 meter from the ground surface; Step 6: In the well body (1), the area from the medium sand (5) to the ground surface is filled with cohesive soil (6); Step 7: Before excavating the foundation pit, dewatering work is carried out by the well point dewatering pipe (4) set in the well body (1) and the corresponding well point dewatering equipment (7) to lower the groundwater level.

2. The construction method according to claim 1, which uses vertical buried heat exchange pipe wells as wellpoint dewatering wells, is characterized in that... After completing the precipitation work, perform the following steps: Step 8: Pull out the wellpoint dewatering pipe (4) and remove the corresponding wellpoint dewatering equipment (7); Step 9: Fill the gap created by pulling out the well point dewatering pipe (4) in the well body (1) with cement grout. Step 10: After completing all construction, connect the heat pipe (2) to the HVAC equipment. The heat transfer liquid in the heat pipe (2) circulates within the heat pipe (2) to achieve ground source heat exchange.

3. The construction method according to claim 1, which uses vertical buried heat exchange pipe wells as wellpoint dewatering wells, is characterized in that... The mixture (3) includes sand and bentonite.

Images