A tunnel base concrete heat dissipation system and a design method of heat dissipation fins

Abstract

The application relates to a tunnel base concrete heat dissipation system and a design method of heat dissipation fins, relates to the tunnel pouring heat dissipation technical field, and aims to solve the problem that the existing heat dissipation structure cannot meet the heat dissipation requirement of the tunnel base concrete after pouring. The tunnel base concrete heat dissipation system is used for heat dissipation of the tunnel base concrete after pouring, and comprises a supply device and a plurality of heat dissipation devices. The plurality of heat dissipation devices extend along the length direction of the tunnel base, and the plurality of heat dissipation devices are arranged at intervals along the width direction of the tunnel base. The plurality of heat dissipation devices each comprise a main pipeline and a plurality of heat dissipation fins. One end of the main pipeline is connected with the output end of the supply device, and the other end is connected with the return flow end of the supply device. The plurality of heat dissipation fins are arranged at intervals along the axial direction of the main pipeline, and the diameters of the heat dissipation fins arranged on the main pipeline gradually increase first and then gradually decrease from one end to the other end of the main pipeline.

Description

Technical Field

[0001] This application relates to the field of heat dissipation technology in tunnel casting, and more specifically, to a design method for a heat dissipation system for tunnel foundation concrete and heat dissipation fins. Background Technology

[0002] With the rapid development of modern tunnel engineering technology, tunnel structural design is increasingly trending towards larger cross-sections and longer spans. As a key structural layer bearing the loads from the superstructure, the construction quality of the tunnel foundation concrete directly affects the safety and durability of the entire tunnel. Currently, the construction of a secondary lining filling layer structure with an invert arch is commonly used, with a single pouring volume exceeding 100 cubic meters, and the length of longitudinal pouring units has expanded to 12 meters, showing a continuing trend of lengthening.

[0003] During concrete pouring, the cement hydration reaction generates a significant amount of heat. Large-volume concrete, with its relatively small heat dissipation area to volume ratio, is prone to internal heat accumulation, leading to temperature stress cracks. Traditional cooling methods primarily rely on serpentine cooling pipe systems to remove some heat through circulating cooling water. However, this arrangement suffers from inherent drawbacks such as limited contact area between the pipes and concrete and low heat exchange efficiency, making it particularly difficult to effectively cool the high-temperature core of the concrete and areas of concentrated heat in irregularly shaped structures. The existing cooling systems are increasingly facing a contradiction between their cooling capacity and engineering requirements when dealing with ultra-long and ultra-large-volume concrete pours.

[0004] Therefore, there is an urgent need to provide a design method for a heat dissipation system and heat dissipation fins to solve the above problems to some extent. Summary of the Invention

[0005] The purpose of this application is to provide a design method for a heat dissipation system and heat dissipation fins for tunnel foundation concrete, so as to solve to some extent the problem that existing heat dissipation structures cannot meet the heat dissipation requirements after the tunnel foundation concrete is poured.

[0006] To achieve the above objectives, the tunnel foundation concrete heat dissipation system provided in this application is used to dissipate heat after the tunnel foundation concrete has been poured, including a supply device and multiple heat dissipation devices; the multiple heat dissipation devices extend along the length direction of the tunnel foundation and are spaced apart along the width direction of the tunnel foundation; each of the multiple heat dissipation devices includes a main pipe and multiple heat dissipation fins, one end of the main pipe is connected to the output end of the supply device, and the other end is connected to the return end of the supply device; the multiple heat dissipation fins are spaced apart along the axial direction of the main pipe, and the diameter of the heat dissipation fins on the main pipe gradually increases and then gradually decreases from one end of the main pipe to the other end.

[0007] The heat dissipation fins include a fin body, a sleeve, and a locking member. The sleeve is coaxially arranged with the fin body, and the inner diameter of the sleeve is adapted to the main pipe. The sleeve is slidable on the main pipe. The locking member is movably connected to the sleeve and extends radially along the sleeve. One end of the locking member can pass through the sleeve and move towards or away from the outer wall of the main pipe.

[0008] Specifically, there are multiple locking elements, and the multiple locking elements are evenly distributed along the circumference of the socket portion.

[0009] Specifically, the outer wall of the main pipe has a first threaded portion, which covers one end of the main pipe to the other end, and the inner ring wall of the plate portion has a second threaded portion, and the plate portion is threadedly connected to the main pipe.

[0010] The heat dissipation fins are hollow, and a receiving cavity is formed inside the heat dissipation fins. The main pipe has a connecting port corresponding to the position of the heat dissipation fins, and the receiving cavity is connected to the main pipe through the connecting port.

[0011] Specifically, the heat dissipation fins at the same axial position of the main pipe include multiple heat dissipation bridges, which are distributed circumferentially along the main pipe, and the inlet and outlet ends of the heat dissipation bridges are connected to the main pipe.

[0012] Furthermore, the sheet portion has a disc-shaped structure or multiple sheet-shaped structures evenly distributed along the circumference of the main pipe.

[0013] The heat dissipation fins are spiral fins, which are arranged spirally from one end of the main pipe to the other end.

[0014] Specifically, the spiral fins are hollow. The supply device includes a first liquid supply component and a second liquid supply component. The output end of the first liquid supply component is connected to one end of the main pipe, and the other end of the main pipe is connected to the return end of the first liquid supply component. The output end of the second liquid supply component is connected to one end of the spiral fins, and the other end of the spiral fins is connected to the return end of the second liquid supply component.

[0015] Compared with existing technologies, the heat dissipation system provided in this application has the following advantages:

[0016] The tunnel foundation concrete heat dissipation system provided in this application is used to dissipate heat after the tunnel foundation concrete is poured. It includes a supply device and multiple heat dissipation devices. The multiple heat dissipation devices extend along the length direction of the tunnel foundation and are spaced apart along the width direction of the tunnel foundation. Each of the multiple heat dissipation devices includes a main pipe and multiple heat dissipation fins. One end of the main pipe is connected to the output end of the supply device, and the other end is connected to the return end of the supply device. The multiple heat dissipation fins are spaced apart along the axial direction of the main pipe, and the diameter of the heat dissipation fins on the main pipe gradually increases and then gradually decreases from one end of the main pipe to the other end.

[0017] This analysis shows that by installing heat dissipation devices along the length of the tunnel foundation, the heat dissipation requirements along the length of the tunnel foundation can be met. Furthermore, by installing multiple heat dissipation devices at intervals along the width of the tunnel foundation, the heat dissipation capacity can be further guaranteed and the heat dissipation effect can be improved.

[0018] The heat dissipation device provided in this application includes a main pipe and multiple heat dissipation fins. The main pipe can be connected to a supply device to enable the input of cooling medium, and then the cooling medium can be used to achieve heat exchange with the concrete to meet the heat dissipation requirements.

[0019] Understandably, this application further arranges multiple heat dissipation fins on the main pipeline, with the diameter of the heat dissipation fins gradually increasing and then gradually decreasing from one end of the main pipeline to the other. This allows for a larger contact area in the middle section to address the heat dissipation state after the tunnel foundation concrete is poured, enabling the heat to be absorbed and discharged through the cooling medium flowing inside the main pipeline. Since the ends or near the ends of the tunnel foundation concrete can dissipate heat more quickly, using smaller diameter heat dissipation fins can also, to some extent, avoid the problem of the fins affecting the density of the reinforcing steel arrangement, thereby affecting the compactness of the poured concrete.

[0020] Furthermore, this application also provides a design method for heat dissipation fins in tunnel foundation concrete, used to design heat dissipation fins in the aforementioned tunnel foundation concrete heat dissipation system, comprising the following steps: Step 1: Determine the time t required for concrete heat dissipation and the ambient temperature T3; Step 2: Divide the concrete heating state into slices along the layout direction of the main pipeline, wherein the smallest unit L should be ≥ 3 times the maximum particle size D of the coarse aggregate in the poured concrete; Step 3: Determine the peak temperature T1 of the concrete hydration heat at any point inside, at which time the apparent temperature T2 of the concrete and the temperature T3 of the coolant inside the pipe; Step 4: Calculate the released heat Q, the overall heat transfer coefficient U, and the logarithmic mean temperature difference Lmtd of the concrete unit, wherein: ; ; ma: Mass of high-temperature solid a (kg); C: Specific heat capacity at constant pressure of concrete unit (unit: J / (kg・℃)); Convective heat transfer coefficient of fluid inside the pipe (unit: W / (m)) 2 •K));δ pipe wall thickness (m); The thermal conductivity of the pipe material (unit: W / (m•K)); External solid convective heat transfer coefficient (unit: W / (m)) 2 •K)), η fin efficiency; Step 5: Calculate the fin area required for the concrete unit: When the fins are circular: ;in The area of ​​a single heat dissipation fin. The unit is the outer surface area of ​​the main pipe.

[0021] The design method for heat dissipation fins of tunnel foundation concrete provided in this application can be used to design heat dissipation fins of different diameters according to the heat generation of concrete at different locations. This can better match the heat dissipation of concrete at the corresponding locations, meet the heat dissipation requirements, avoid cracking and other problems during the concrete molding process, and ensure molding quality.

[0022] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of the heat dissipation device provided in the first embodiment of this application;

[0025] Figure 2 A schematic diagram showing the arrangement of the heat dissipation device provided in this application on the tunnel foundation;

[0026] Figure 3 Schematic diagrams of partial structures of the heat dissipation devices provided in the second and fourth embodiments of this application;

[0027] Figure 4 This is a schematic diagram of the heat dissipation device provided in the third embodiment of this application;

[0028] Figure 5 This is a schematic diagram of the heat dissipation device provided in the fifth embodiment of this application;

[0029] Figure 6 Schematic diagram of other morphologies of heat dissipation fins in the heat dissipation device provided in the first embodiment of this application;

[0030] Figure 7 This is a schematic diagram of other forms of heat dissipation fins in the heat dissipation device provided in the first embodiment of this application.

[0031] Icons: 1-Main pipe; 101-First threaded part; 102-Connecting port; 2-Heat dissipation fins; 201-Fin body part; 202-Sleeve part; 203-Locking part; 3-Heat dissipation bridge part; 301-Liquid inlet end; 302-Liquid outlet end. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] In the description of this application, it should be noted that the terms "inner" and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0034] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0035] Example 1

[0036] like Figure 1 Combination Figure 2As shown, the tunnel foundation concrete heat dissipation system provided in this application is used to dissipate heat after the tunnel foundation concrete is poured. It includes a supply device and multiple heat dissipation devices. The multiple heat dissipation devices extend along the length direction of the tunnel foundation and are spaced apart along the width direction of the tunnel foundation. Each of the multiple heat dissipation devices includes a main pipe 1 and multiple heat dissipation fins 2. One end of the main pipe 1 is connected to the output end of the supply device, and the other end is connected to the return end of the supply device. The multiple heat dissipation fins 2 are spaced apart along the axial direction of the main pipe 1, and the diameter of the heat dissipation fins 2 on the main pipe 1 gradually increases and then gradually decreases from one end of the main pipe 1 to the other end.

[0037] Compared with existing technologies, the tunnel foundation concrete heat dissipation system provided in this application has the following advantages:

[0038] The tunnel foundation concrete heat dissipation system provided in this application can meet the heat dissipation requirements along the length of the tunnel foundation by setting heat dissipation devices along the length of the tunnel foundation. Furthermore, by setting multiple heat dissipation devices at intervals along the width of the tunnel foundation, the heat dissipation capacity can be further guaranteed and the heat dissipation effect can be improved.

[0039] The tunnel foundation concrete heat dissipation device provided in this application includes a main pipe 1 and multiple heat dissipation fins 2. The main pipe 1 can be connected to a supply device to enable the input of cooling medium, thereby achieving heat exchange between the cooling medium and the concrete to meet the heat dissipation requirements.

[0040] It is understandable that this application further arranges multiple heat dissipation fins 2 on the main pipe 1, and the diameter of the heat dissipation fins 2 gradually increases and then gradually decreases from one end of the main pipe 1 to the other end. This allows for a larger contact area in the middle position to address the heat dissipation state after the tunnel foundation concrete is poured, thereby enabling the heat to be absorbed and discharged through the cooling medium flowing in the main pipe 1. Since the ends or near the ends of the tunnel foundation concrete can dissipate heat faster, using smaller diameter heat dissipation fins 2 can also, to some extent, avoid the problem of the fins affecting the density of the reinforcing steel arrangement, thus affecting the compactness of the poured concrete.

[0041] It should be further explained here that, in this embodiment, the heat dissipation fins 2 can be connected to the main pipe 1 by welding. That is, in this embodiment, the heat dissipation fins 2 and the main pipe 1 are separate structures before assembly. This allows the diameter requirements of the heat dissipation fins 2 to be obtained according to the heat dissipation fins 2 design method provided in this application. Then, multiple heat dissipation fins 2 with different diameters can be assembled along the length of the main pipe 1 according to the corresponding requirements. After that, a stable connection between the heat dissipation fins 2 and the main pipe 1 can be achieved by welding.

[0042] In this embodiment, the heat dissipation fins 2 are as follows: Figure 1As shown, circular fins are used, but they can also be arranged as shown in the diagram. Figure 6 or Figure 7 The fin morphology shown is as follows, and as Figure 6 and Figure 7 The fins shown are located on both sides, which can be understood as two in number, but the number of fins can also be four, such as forming a four-leaf clover shape. The shape of the fins can also be further designed into other forms according to the needs, such as fan-shaped or rectangular, or even needle-shaped heat dissipation fins 2. Of course, if needle-shaped heat dissipation fins 2 are used, the number of needle clusters can be gradually increased and then gradually decreased from one end of the main pipe 1 to the other end, or the length of the needle clusters can be gradually increased and then gradually shortened from one end of the main pipe 1 to the other end.

[0043] Example 2

[0044] like Figure 3 Combination Figure 4 As shown, the heat dissipation fin 2 in this application includes a fin body 201, a sleeve portion 202, and a locking member 203; the sleeve portion 202 is coaxially arranged with the fin body 201, and the inner diameter of the sleeve portion 202 is adapted to the main pipe 1, and the sleeve portion 202 can slide on the main pipe 1; the locking member 203 is movably connected to the sleeve portion 202, the locking member 203 extends radially along the sleeve portion 202, and one end of the locking member 203 can pass through the sleeve portion 202 and move towards or away from the outer wall of the main pipe 1.

[0045] In this embodiment, by designing a sleeve 202 connected to the sheet portion 201 and a locking member 203 with one end passing through the sleeve 202 to abut or separate from the main pipe 1, the position of the sheet portion 201 and the main pipe 1 can be fixed and the position can be adjusted.

[0046] In this embodiment, the heat dissipation fins 2 can be adjusted in position before welding and initially fixed in position after adjustment. Of course, in this embodiment, the diameter of the multiple heat dissipation fins 2 connected to the main pipe 1 is still selected and arranged in the manner of embodiment 1. The difference is that when installing the heat dissipation fins 2, the heat dissipation fins 2 are first put on the main pipe 1 and slid to the corresponding position. Then, the locking member 203 is used to initially lock the heat dissipation fins 2. Finally, the heat dissipation fins 2 are fixedly connected to the main pipe 1 by welding to ensure stability.

[0047] It is understandable that by designing the socket 202 and the locking member 203, the heat sink fins 2 can be initially locked, so that no other personnel are needed to assist in the welding stage, and the position can be kept accurate, avoiding the movement during the welding process that affects the positional accuracy.

[0048] Optionally, in this embodiment, there are multiple locking members 203, and the multiple locking members 203 are evenly distributed along the circumference of the sleeve portion 202.

[0049] Preferably, in this embodiment, there are four locking elements 203. After the heat dissipation fins 2 slide into place, the four circumferentially distributed locking elements 203 can lock the heat dissipation fins 2 and the main pipe 1 to ensure the accurate position of the heat dissipation fins 2. In this application, the locking elements 203 are bolts, which can achieve quick contact between the locking elements 203 and the outer wall of the main pipe 1. At the same time, when the position needs to be adjusted before welding, the bolts can be loosened directly to unlock the heat dissipation fins 2, thereby achieving the position adjustment.

[0050] Example 3

[0051] like Figure 4 As shown, the outer wall of the main pipe 1 in this application has a first threaded portion 101, which covers one end of the main pipe 1 to the other end. The inner ring wall of the sheet portion 201 has a second threaded portion, and the sheet portion 201 is threadedly connected to the main pipe 1.

[0052] In this embodiment, the structure of the main pipe 1 is further optimized, such that a first threaded portion 101 is formed on the outer wall of the main pipe 1, and as shown... Figure 4 As shown, the first threaded portion 101 covers one end of the main pipe 1 to the other end, thereby enabling the installation of multiple heat dissipation fins 2.

[0053] Accordingly, in any embodiment, a through hole is provided at the center of the plate portion 201. Therefore, in this embodiment, a second threaded portion is formed on the inner ring wall of the through hole. When the first threaded portion 101 is an external thread, the second threaded portion is an internal thread. However, preferably, the first threaded portion 101 in this application is an internal thread. Since the main pipe 1 needs to be laid, it may come into contact with and collide with structures such as positioning steel bars during the laying process. Therefore, the formed internal thread can avoid collision damage to the thread teeth to a certain extent, which would affect the smoothness of the rotation process of the heat dissipation fins 2.

[0054] It is understandable that the first threaded part 101 and the second threaded part can also achieve the initial positioning of the heat dissipation fins 2 relative to the main pipe 1, thereby avoiding the problem of slippage caused by contact during welding.

[0055] Of course, such as Figure 4 As shown, in this embodiment, the heat dissipation fin 2 can also adopt the structure with sleeve 202 and locking member 203 as in embodiment 2. With this form, the welding process can be eliminated. That is, the fin body 201 is first rotated to a predetermined position by thread engagement, and then the locking member 203 abuts against the first threaded part 101. At this time, the locking member 203 can be a screw, so that it can better cooperate with the first threaded part 101 to fix the position of the fin body 201.

[0056] Example 4

[0057] In this embodiment, as Figure 3 As shown, the heat dissipation fin 2 has a hollow structure and a receiving cavity is formed inside the heat dissipation fin 2. The main pipe 1 has a connecting port 102 corresponding to the position of the heat dissipation fin 2. The receiving cavity is connected to the main pipe 1 through the connecting port 102.

[0058] The hollow heat dissipation fins 2 can carry the cooling medium, thereby allowing the cooling medium to better absorb the heat emitted by the concrete. However, when the heat dissipation fins 2 are hollow and the main pipe 1 has a corresponding connection port 102, the heat dissipation fins 2 must be connected to the main pipe 1 by welding to avoid leakage of the cooling medium.

[0059] Example 5

[0060] like Figure 5 As shown, in this embodiment, the heat dissipation fins 2 at the same axial position of the main pipe 1 include multiple heat dissipation bridges 3, which are distributed along the circumference of the main pipe 1, and the liquid inlet end 301 and liquid outlet end 302 of the heat dissipation bridge 3 are both connected to the main pipe 1.

[0061] like Figure 5 As shown, the heat dissipation bridge 3 provided in this embodiment is arranged in a bridge or arch shape outside the main pipe 1 from the liquid inlet end 301 to the liquid outlet end 302. The heat dissipation bridge 3 in this application can be designed with multiple bridges in the circumferential direction, so as to meet the heat dissipation requirements. Correspondingly, the cooling medium enters the heat dissipation bridge 3 from the liquid inlet end 301 and flows back into the main pipe 1 from the liquid outlet end 302, carrying the heat dissipated by the concrete in contact with the heat dissipation bridge 3, thereby achieving the purpose of heat dissipation.

[0062] In this embodiment, the height of the arched heat dissipation bridge 3 located at the end of the main pipe 1 is less than the height located in the middle of the main pipe 1. That is, the height of the heat dissipation bridge 3 at multiple locations along the length of the main pipe 1 gradually increases from one end to the other and then gradually decreases to adapt to the heat dissipation of the concrete at the corresponding location.

[0063] Example 6

[0064] In this embodiment, the heat dissipation fins 2 are spiral fins, which are arranged in a spiral pattern from one end of the main pipe 1 to the other end.

[0065] Preferably, the hollow structure of the spiral fin supply device includes a first liquid supply component and a second liquid supply component. The output end of the first liquid supply component is connected to one end of the main pipe 1, and the other end of the main pipe 1 is connected to the return end of the first liquid supply component. The output end of the second liquid supply component is connected to one end of the spiral fin, and the other end of the spiral fin is connected to the return end of the second liquid supply component.

[0066] Because the spiral fins are formed to be longer, by designing the spiral fins in a hollow form, the cooling medium can have a longer flow time, thereby absorbing more heat. Accordingly, in this embodiment, the diameter of the spiral fins can also gradually increase from one end of the main pipe 1 to the other end, and then gradually decrease.

[0067] Furthermore, since this application further adds a second liquid supply component, it is possible to supply cooling medium to the spiral fins, thereby enabling the cooling medium in the spiral fins to absorb the heat of the concrete. The cooling medium in the main pipe 1 absorbs the heat of the spiral fins and part of the concrete to ensure heat absorption capacity and avoid cracking during the cooling and solidification process.

[0068] It should be noted that in this application, both the first and second liquid supply components can adopt a structure of a pump body, a connecting pipeline, and a cooling pool. That is, the pump body is connected to the main pipe 1 or the spiral fins through the connecting pipeline, the pump body realizes the input of the cooling medium, the connecting pipeline further realizes the return of the cooling medium, and the cooling pool realizes the holding and cooling of the cooling medium, so as to ensure the temperature of the cooling medium flowing to the pump body.

[0069] Furthermore, this application also provides a design method for heat dissipation fins 2, used to design heat dissipation fins 2 in the aforementioned tunnel foundation concrete heat dissipation system, including the following steps: Step 1: Determine the time t required for concrete heat dissipation and the ambient temperature T3; Step 2: Divide the concrete heating state into slices along the layout direction of the main pipe 1, the smallest unit L of the division should be ≥ 3 times the maximum particle size D of the coarse aggregate in the poured concrete; Step 3: Determine the peak temperature T1 of the concrete hydration heat at any point inside, the apparent temperature T2 of the concrete at this time, and the temperature T3 of the coolant inside the pipe; Step 4: Calculate the released heat Q, the overall heat transfer coefficient U, and the logarithmic mean temperature difference Lmtd of the concrete unit, where: ; ; ma: Mass of high-temperature solid a (kg); C: Specific heat capacity at constant pressure of concrete unit (unit: J / (kg・℃)); Convective heat transfer coefficient of fluid inside the pipe (unit: W / (m)) 2 •K));δ pipe wall thickness (m); The thermal conductivity of the pipe material (unit: W / (m•K)); External solid convective heat transfer coefficient (unit: W / (m)) 2 •K)), η fin efficiency; Step 5: Calculate the fin area required for the concrete unit: When the fins are circular: ;in The area of ​​a single heat dissipation fin 2, The outer surface area of ​​the main pipe 1 is given.

[0070] By adopting the heat dissipation fin 2 design method provided in this application, heat dissipation fins 2 with different diameters can be designed according to the heat generation of concrete at different locations, so as to better match the heat dissipation of concrete at the corresponding locations, meet the heat dissipation requirements, avoid cracking and other problems during the concrete molding process, and ensure molding quality.

[0071] Calculations show that the diameter of the main pipe 1 in this application is 100mm, which is more suitable for long-distance transportation and avoids problems such as blockage of cooling medium or slow flow affecting heat dissipation.

[0072] Furthermore, the large-diameter main pipe 1 can be directly filled with concrete after the cooling process is completed, which can also ensure the fluidity of the concrete.

[0073] It should be noted here that the design method for heat dissipation fins in tunnel foundation concrete provided in this application is mainly based on Figure 1 Based on the circular fins shown, the diameter of the heat dissipation fin 2 is obtained through finite element analysis, which shows that the diameter gradually increases and then gradually decreases from one end of the main pipe 1 to the other. Therefore, the shape of the heat dissipation fin 2 can be further changed based on this, but the size change of the heat dissipation fin 2 still needs to be carried out in the manner of gradually increasing and then decreasing, and the spacing of each heat dissipation fin 2 should be kept consistent to ensure the stress balance after the subsequent concrete pouring.

[0074] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0075] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A design method for heat dissipation fins in tunnel foundation concrete, used to design heat dissipation fins in a tunnel foundation concrete heat dissipation system, characterized in that, The tunnel foundation concrete heat dissipation system is used to dissipate heat after the tunnel foundation concrete is poured, and includes a supply device and multiple heat dissipation devices. The plurality of heat dissipation devices extend along the length direction of the tunnel base, and the plurality of heat dissipation devices are spaced apart along the width direction of the tunnel base; Each of the aforementioned heat dissipation devices includes a main pipe and multiple heat dissipation fins. One end of the main pipe is connected to the output end of the supply device, and the other end is connected to the return end of the supply device. Multiple heat dissipation fins are spaced apart along the axial direction of the main pipe, and the diameter of the heat dissipation fins on the main pipe gradually increases and then gradually decreases from one end of the main pipe to the other end. The heat dissipation fins at the same axial position of the main pipe include multiple heat dissipation bridges, which are distributed circumferentially along the main pipe, and the liquid inlet and liquid outlet of the heat dissipation bridges are connected to the main pipe. The design method for heat dissipation fins in tunnel foundation concrete includes the following steps: Step 1: Determine the time t required for the concrete to dissipate heat and the ambient temperature; Step 2: Divide the concrete heating state into sections along the layout direction of the main pipeline, with the smallest unit L being ≥ 3 times the maximum particle size D of the coarse aggregate in the poured concrete. Step 3: Determine the peak temperature T1 of the concrete hydration heat at any point inside the pipe, the apparent temperature T2 of the concrete, and the temperature T3 of the coolant inside the pipe. Step 4: Calculate the heat released Q, overall heat transfer coefficient U, and logarithmic mean temperature difference Lmtd for each concrete unit, where: ； ; ； m a Mass of high-temperature solid a, in kg; C: Specific heat capacity under constant pressure of concrete unit, in J / (kg・℃); The convective heat transfer coefficient of the fluid inside the pipe, expressed in W / (m²). 2 •K); δ represents the pipe wall thickness, in meters (m). The thermal conductivity of the pipe is expressed in W / (m·K). The convective heat transfer coefficient of the solid outside the tube is expressed in W / (m²). 2 •K), where η is the fin efficiency; Step 5: Calculate the required fin area for the concrete unit: ； in The area of ​​a single heat dissipation fin. The unit is the outer surface area of ​​the main pipe.

2. The design method for heat dissipation fins in tunnel foundation concrete according to claim 1, characterized in that, The heat dissipation fins include a fin body, a sleeve part, and a locking element; The socket portion is coaxially arranged with the sheet portion, and the inner diameter of the socket portion is adapted to the main pipe. The socket portion can slide on the main pipe. The locking member is movably connected to the socket portion. The locking member extends radially along the socket portion, and one end of the locking member can pass through the socket portion and move towards or away from the outer wall of the main pipe.

3. The design method for heat dissipation fins of tunnel foundation concrete according to claim 2, characterized in that, There are multiple locking elements, and the multiple locking elements are evenly distributed along the circumference of the sleeve portion.

4. The design method for heat dissipation fins in tunnel foundation concrete according to claim 2, characterized in that, The outer wall of the main pipe has a first threaded portion, which covers one end of the main pipe to the other end. The inner ring wall of the sheet portion has a second threaded portion, and the sheet portion is threadedly connected to the main pipe.

5. The design method for heat dissipation fins in tunnel foundation concrete according to claim 1, characterized in that, The heat dissipation fins are hollow, and a receiving cavity is formed inside the heat dissipation fins. The main pipe has a connecting port corresponding to the position of the heat dissipation fins, and the receiving cavity is connected to the main pipe through the connecting port.

6. The design method for heat dissipation fins in tunnel foundation concrete according to claim 2, characterized in that, The sheet portion has a disc-shaped structure or multiple sheet-shaped structures evenly distributed along the circumference of the main pipe.

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