Structure for preventing cooling tower PHC pile splicing joint foundation soil corrosion and design method thereof

Abstract

The invention provides a structure for preventing foundation soil of a cooling tower PHC pile splicing connector from being corroded and a design method of the structure. The structure comprises the pile splicing connector, a pile top steel end plate, a cathode protection wire, a cathode protection outgoing line, an anode cable and sacrificial anodes, and the sacrificial anodes are connected with the anode cable and used for bearing current flowing through the pile splicing connector; wherein the potential value of the sacrificial anode is lower than that of the pile splicing joint, and metal corrosion of the pile splicing joint is replaced by oxidation reaction. According to the method, the conductors are arranged in a multi-layer mode to conduct reliable electric connection on steel of the PHC pile splicing connector, meanwhile, the number of sacrificial anodes meeting the working life limit is calculated and configured according to the number and scale of PHC piles and the foundation soil corrosion environment, and the problem that the PHC pile splicing connector is prone to damage in the pile sinking process due to the fact that an anti-corrosion coating is adopted is solved; the problems of corrosion prevention and durability of the PHC pile in a corrosive soil environment are solved, and the anti-corrosion engineering quality of the pile splicing joint of the PHC pile is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of cooling tower design, and more specifically, to a structure for preventing the corrosion of the foundation soil at the PHC pile splicing joint of a cooling tower and its design method. Background Art

[0002] The pool of a natural ventilation or mechanical ventilation wet cooling tower is an open reinforced concrete structure. When the cooling tower is located in a soil layer with low bearing capacity, low compression modulus and large thickness, pile foundations are usually used for foundation treatment to bear the load transmitted from the upper structure of the cooling tower. Pretensioned high-strength concrete piles (PHC) are a new type of building material, which are manufactured and produced in factories in a standardized manner, and have the advantages of high strength, low price, good quality, fast construction speed, strong adaptability, etc. At present, they are more and more widely used in the foundation treatment of cooling towers. For the convenience of manufacturing, transportation, storage, hoisting and pile driving construction, PHC piles are divided into different specifications and sizes according to the outer diameter, model, wall thickness and length. Each PHC pile is composed of several standard sections according to the magnitude of the load it bears. The prestressed steel bars of the pile body of each standard section are anchored on the steel end plates at both ends, and the steel end plates are then welded to the annular pile steel hoop. The pile body is lengthened by welding the steel end plates between the standard sections to meet the bearing capacity requirements of the design. Usually, a PHC pile is composed of 2 - 5 standard sections and has 1 - 4 splicing joints.

[0003] Due to the above structural characteristics, the prestressed steel bars, end plates and pile hoops of the PHC pile form an electrical connection. When the PHC pile is in a corrosive foundation soil environment (when the soil resistivity of the foundation is between 20 - 50 Ω·m, it has medium corrosion to steel structures; when the soil resistivity is less than 20 Ω·m, it has strong corrosion to steel structures), the steel of the splicing joint will be corroded and damaged, thus affecting the durability and bearing capacity of the pile. Therefore, anti-corrosion treatment is generally required for the splicing joint; the anti-corrosion measure usually adopts anti-corrosion coating.

[0004] However, even with anti-corrosion measures in actual operation, there is still a great corrosion risk for PHC piles. Through research and experimental verification, it is found that most PHC piles are friction piles, and the pile driving method of hammer-driven pile or jacked pile is adopted; during the pile driving process, the splicing joint will inevitably rub against the surrounding soil layer. The huge friction force will damage the anti-corrosion coating of the splicing joint, causing the failure of the coating anti-corrosion coating, and then leading to the corrosion of the pile body steel, such as the joint weld, end plate, pile hoop, pile tip and even the prestressed steel bars of the pile body, reducing the durability and reliability of the PHC pile, and seriously endangering the safety and stability of the cooling tower foundation and the upper structure in severe cases. Summary of the Invention

[0005] The present invention aims to solve at least one of the above technical problems existing in the prior art.

[0006] To this end, a first aspect of the present invention provides a structure for preventing the corrosion of the foundation soil at the joint of PHC piles in a cooling tower.

[0007] A second aspect of the present invention provides a design method for a structure for preventing the corrosion of the foundation soil at the joint of PHC piles in a cooling tower.

[0008] The present invention provides a structure for preventing the corrosion of the foundation soil at the joint of PHC piles in a cooling tower. The cooling tower includes a pool bottom plate and a ring foundation. A number of ground beams are arranged on the pool bottom plate. A number of the PHC piles are respectively connected to the ring foundation and the ground beams. The structure includes:

[0009] A pile joint for longitudinally connecting the standard sections of the PHC piles and thus bearing the loads of the ring foundation and the pool bottom plate;

[0010] A pile top steel end plate provided at the end of the PHC pile to form a connection surface. The pile top steel end plate is electrically connected to the prestressed tendons embedded in the PHC pile;

[0011] A cathodic protection wire electrically connected to the pile top steel end plate;

[0012] A cathodic protection lead-out wire connected to a number of the cathodic protection wires and provided with a lead-out end. The current flowing through the pile joint is led out to the outside of the cooling tower through the lead-out end;

[0013] An anode cable arranged around the cooling tower. The lead-out end of the cathodic protection lead-out wire is electrically connected to the anode cable;

[0014] Sacrificial anodes. A number of sacrificial anodes are connected to the anode cable and used to carry the current flowing through the pile joint. Among them, the potential value of the sacrificial anode is lower than the potential value of the pile joint, and the metal corrosion occurring at the pile joint is replaced through an oxidation reaction.

[0015] According to the above technical solution of the present invention, the structure for preventing the corrosion of the foundation soil at the joint of PHC piles in a cooling tower may further have the following additional technical features:

[0016] In the above technical solution, the cathodic protection wire is selected as the stressed reinforcement bars in the ring foundation and the ground beams.

[0017] In the above technical solution, it further includes:

[0018] A cathodic protection connection provided between the connection surface and the cathodic protection wire to achieve the electrical connection between the cathodic protection wire and the pile top steel end plate.

[0019] In the above technical solution, the current flowing through the pile joint is sequentially transmitted to the sacrificial anode through the pile joint, the pile top steel end plate, the cathodic protection connection, the cathodic protection wire, the cathodic protection lead-out wire, and the anode cable.

[0020] In the above technical solution, the cathodic protection lead wire is selected as galvanized flat steel;

[0021] and / or, the sacrificial anode is selected as magnesium alloy or zinc alloy.

[0022] In the above technical solution, the anode cable is selected as the existing horizontal grounding grid arranged around the foundation of the cooling tower.

[0023] A design method for a structure to prevent the foundation soil corrosion of the PHC pile splicing joint of a cooling tower provided by the present invention is used to design the structure for preventing the foundation soil corrosion of the PHC pile splicing joint of a cooling tower as described in any of the above technical solutions. The design method includes:

[0024] According to the structural characteristics and load distribution characteristics of the cooling tower, determine the structural parameters and total quantity of the PHC piles. The structural parameters include the type, diameter, wall thickness, length, and the number of splicing joints of the PHC piles;

[0025] Calculate the protection area and protection current of the cathodic protection of the splicing joint according to the structural parameters and total quantity of the PHC piles;

[0026] Calculate its grounding resistance, generated current, service life, and the total quantity of sacrificial anodes according to the physical parameters of the sacrificial anode.

[0027] According to the structure for preventing the foundation soil corrosion of the PHC pile splicing joint of the cooling tower in the above technical solution of the present invention, it may also have the following additional technical features:

[0028] In the above technical solution, the structural characteristics and load distribution characteristics of the cooling tower include the structural characteristics and load distribution characteristics of the ventilation cylinder, water distribution filler device, ring foundation, and pool bottom slab.

[0029] In the above technical solution, calculating the total protection area and total protection current of the cathodic protection of the splicing joint according to the structural parameters and total quantity of the PHC piles includes:

[0030]

[0031] I = A·S

[0032] Among them, S represents the total protection area; S i represents the cathodic protection area of the splicing joint on the i-th PHC pile; n represents the total quantity of PHC piles; A represents the cathodic protection current density, which is determined according to the soil resistivity; I represents the total protection current.

[0033] In the above technical solution, calculating its grounding resistance, generated current, service life, and the total quantity of sacrificial anodes according to the physical parameters of the sacrificial anode includes:

[0034] Calculating the grounding resistance of a single sacrificial anode, including:

[0035]

[0036] Among them, R represents the grounding resistance of a single sacrificial anode; ρ represents the soil resistivity; L represents the anode length; D1 represents the diameter of the filler pack of the sacrificial anode; L1 represents the length of the filler pack of the sacrificial anode; t represents the distance from the center of the sacrificial anode to the ground; ρ1 represents the resistivity of the filler of the sacrificial anode; D represents the equivalent diameter of the sacrificial anode;

[0037] Calculating the generated current of a single sacrificial anode, including:

[0038]

[0039] Among them, I f represents the generated current of a single sacrificial anode; ΔE represents the anode driving potential, which is determined according to the material selection of the sacrificial anode;

[0040] Calculating the service life of the sacrificial anode, including:

[0041]

[0042] Among them, Y represents the service life of the sacrificial anode; Q represents the actual capacitance of the sacrificial anode; G represents the mass of a single sacrificial anode; I m represents the average generated current of a single anode, I m = 0.7I f ; 1 / K represents the anode utilization factor;

[0043] Calculating the total number of sacrificial anodes, including:

[0044]

[0045] Among them, N represents the total number of sacrificial anodes; B represents the spare factor.

[0046] In summary, due to the adoption of the above technical features, the beneficial effects of the present invention are:

[0047] According to the structural characteristics of the cooling tower ring foundation and the pool floor slab, combined with the structural characteristics of PHC piles and the corrosion properties of the foundation soil around the piles, sacrificial anode cathodic protection anti-corrosion measures are adopted for the steel of the PHC pile splicing joint. The existing steel bars of the cooling tower structure and the horizontal grounding grid are used as cathodic protection conductors, and reliable electrical connection is made to the steel of the PHC pile splicing joint through multi-level conductor settings. At the same time, the number of sacrificial anodes that meet the service life is calculated and configured according to the number, scale of PHC piles and the foundation soil corrosion environment, avoiding the problem that the anti-corrosion coating of the PHC pile splicing joint is easily damaged during the pile driving process, solving the anti-corrosion and durability problems of PHC piles in corrosive soil environments, and ensuring the anti-corrosion project quality of the PHC pile splicing joint. The present invention utilizes the existing structure, with low cost, simple design and construction, and has great safety and economic significance.

[0048] The additional aspects and advantages of the present invention will become obvious in the following description part, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0050] Figure 1 is the plan layout diagram of the cooling tower ring foundation and the pool floor slab of an embodiment of the present invention;

[0051] Figure 2 is the partial sectional view of the cooling tower ring foundation and the pool floor slab of an embodiment of the present invention;

[0052] Figure 3 is the partial schematic diagram of the structure for preventing the foundation soil corrosion of the PHC pile splicing joint of the cooling tower of an embodiment of the present invention;

[0053] Figure 4 is the sectional view of the PHC pile of an embodiment of the present invention;

[0054] Figure 5 is the flow chart of the design method of the structure for preventing the foundation soil corrosion of the PHC pile splicing joint of the cooling tower of an embodiment of the present invention.

[0055] Wherein, Figures 1 to 5 the corresponding relationship between the reference numerals in the drawings and the component names is as follows:

[0056] 1. Pool floor slab; 2. Ring foundation; 3. PHC pile; 4. Cathodic protection wire; 5. Cathodic protection lead-out wire; 6. Anode cable; 7. Sacrificial anode; 8. Cathodic protection connection;

[0057] 11. Ground beam;

[0058] 31. Pile connection joint; 32. Steel end plate at pile top; 33. Prestressed tendon. Detailed implementation manners

[0059] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0060] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0061] The following refers to Figures 1 to 5 to describe a structure for preventing the corrosion of the foundation soil of the pile connection joint of the PHC pile of a cooling tower and its design method according to some embodiments of the present invention.

[0062] Some embodiments of the present application provide a structure for preventing the corrosion of the foundation soil of the pile connection joint 31 of the PHC pile 3 of a cooling tower.

[0063] The first embodiment of the present invention proposes a structure for preventing the corrosion of the foundation soil of the pile connection joint 31 of the PHC pile 3 of a cooling tower. As Figure 1 and Figure 2 shown, the cooling tower referred to in the present disclosure at least includes a pool bottom plate 1 and a ring foundation 2. The pool bottom plate 1 is connected to the ring foundation 2, and a plurality of PHC piles 3 are arranged at the bottom of the pool bottom plate 1 and the ring foundation 2 to serve as the foundation of the cooling tower. Among them, a plurality of ground beams 11 are arranged on the pool bottom plate 1, and some PHC piles 3 are connected to the ring foundation 2 to support the ring foundation 2; some PHC piles 3 are connected to the corresponding ground beams 11 to support the pool bottom plate 1. As Figure 3 shown, the structure for preventing the corrosion of the foundation soil of the pile connection joint 31 of the PHC pile 3 in the present disclosure at least includes: a pile connection joint 31, a steel end plate 32 at the pile top, a cathodic protection wire 4, a cathodic protection lead-out wire 5, an anode cable 6, and a sacrificial anode 7.

[0064] The pile connection joint 31 is used for longitudinally connecting the standard sections of the PHC pile 3, and thus bears the loads of the ring foundation 2 and the pool bottom plate 1; as Figure 4 shown, the pile connection joint 31 connects two adjacent standard sections in the axial direction of the PHC pile 3. It can be understood that most of the pile connection joint 31 is made of metal. That is to say, the exposed metal part of the pile connection joint 31 in contact with the soil in the present disclosure is its cathodic protection area. Continuing to refer to Figure 3 , a prestressed tendon 33 is embedded in the pipe wall of the PHC pile 3. The prestressed tendon 33 is made of metal and is necessarily connected to the pile connection joint 31. That is to say, an electrical path is formed between the pile connection joint 31 and the prestressed tendon 33.

[0065] The steel end plate 32 at the pile top is arranged at the end of the PHC pile 3 to form a connection surface, and the steel end plate 32 at the pile top is electrically connected to the prestressed tendons 33 embedded in the PHC pile 3; continue to refer to Figures 1 to 3 , the steel end plate 32 at the pile top is arranged at one end of the PHC pile 3 close to the ground beam 11 or the ring foundation 2, and its main function is to provide a wiring position for the subsequent construction of the current conduction path. In a specific embodiment, the steel end plate 32 at the pile top is annular, covering the end of the PHC pile 3 and extending radially outward along the PHC pile 3 to increase the contact area. Of course, the steel end plate 32 at the pile top does not have to be an integral structure, and a split type can also be used. The shape can also be strip-shaped or irregular as long as it can extend in the desired direction.

[0066] The cathodic protection wire 4 is electrically connected to the steel end plate at the pile top; there can be multiple cathodic protection wires 4, and the same cathodic protection wire 4 can be electrically connected to multiple steel end plates at the pile top. The electrical connection method can be direct contact or indirect, for example, through other conductive parts for transfer. In a specific embodiment, the cathodic protection wire 4 is selected as the stressed reinforcement in the ring foundation 2 and the ground beam 11; according to the actual reinforcement situation of the cooling tower ring foundation 2 and the ground beam 11 of the pool bottom plate 1, the longitudinal stressed reinforcement of the structure is selected as the cathodic protection conductor according to the principle of proximity.

[0067] The cathodic protection lead-out wire 5 is connected to several of the cathodic protection wires 4 and is provided with a lead-out end. The current flowing through the pile joint 31 is led out to the outside of the cooling tower through the lead-out end; specifically, in the present disclosure, part of the cathodic protection lead-out wire 5 is located in the reinforced concrete structure and part is located in the foundation soil layer. From the perspective of convenient construction, a galvanized flat steel is preferably used. In some embodiments, the cathodic protection lead-out wire 5 can adopt a combination of a main line and branch lines to be connected to all the cathodic protection wires 4. The number of main lines of the lead-out wire is not less than 2, which are respectively welded to the anode cable 6 outside the periphery of the cooling tower foundation and each cathodic protection wire 4. The branch lines of the lead-out wire are respectively welded to the main line and each cathodic protection wire 4, and the number is determined according to the cathodic protection wires 4 to be connected. The welding should be firm to ensure good electrical connection.

[0068] The anode cable 6 is arranged around the cooling tower, and the lead-out end of the cathodic protection lead-out wire 5 is electrically connected to the anode cable 6; in a specific embodiment, the anode cable 6 is selected as the existing horizontal grounding grid arranged outside the periphery of the cooling tower foundation. The horizontal grounding grid generally adopts a galvanized flat steel and is welded to the cathodic protection lead-out wire 5. The welding should be firm to ensure good electrical connection.

[0069] The sacrificial anode 7, several sacrificial anodes 7 are connected to the anode cable 6 and are used to carry the current flowing through the pile connection joint 31; wherein, the potential value of the sacrificial anode 7 is lower than the potential value of the pile connection joint 31, and the metal corrosion occurring at the pile connection joint 31 is replaced through an oxidation reaction. In some embodiments, the sacrificial anode 7 adopted in the present disclosure can select a magnesium alloy or a zinc alloy sacrificial anode 7 according to the size of the foundation soil resistivity. For example, when the soil resistivity is between 15 and 150 Ω·m, a magnesium alloy sacrificial anode 7 is adopted; when the soil resistivity is less than 15 Ω·m, a zinc alloy sacrificial anode 7 is adopted.

[0070] In the above setting, through the multi-level setting of conductors, the reliable electrical connection of the steel of the pile connection joint 31 of the PHC pile 3 is achieved. At the same time, a sacrificial anode 7 is configured, solving the problem that the PHC pile 3 is prone to corrosion caused by the easy damage of the anti-corrosion coating of the pile connection joint 31 of the PHC pile 3 during the pile driving process, and ensuring the anti-corrosion project quality of the pile connection joint 31 of the PHC pile 3.

[0071] In some embodiments, the structure further includes a cathodic protection wiring 8; the cathodic protection wiring 8 is arranged between the connection surface and the cathodic protection wire 4 to realize the conductive connection between the cathodic protection wire 4 and the pile top steel end plate. When the cathodic protection wiring 8 is assembled, the current flowing through the pile connection joint 31 sequentially passes through the pile connection joint 31, the pile top steel end plate 32, the cathodic protection wiring 8, the cathodic protection wire 4, the cathodic protection lead-out wire 5 and the anode cable 6 and is transmitted to the sacrificial anode 7.

[0072] The cathodic protection wiring 8 can be laid with a variety of materials, which is not uniquely limited, and steel bars or flat steel can be used; in a specific embodiment, when the cathodic protection wiring 8 adopts steel bars, the shape of the steel bars can be appropriately adjusted to closely fit and welded to the pile top steel end plate 32 and the longitudinal structural stress-bearing steel bars passing through the pile top. The length of the single-sided lap weld is not less than 10d, and the length of the double-sided lap weld is not less than 5d, where d is the diameter of the structural stress-bearing steel bar, and the welding should be firm to ensure good electrical connection.

[0073] It should be noted that the standard section end plates, pile sleeve hoops and other exposed steel of the pile body of the PHC pile 3 for the cooling tower foundation treatment adopted in the present disclosure should be coated with basic anti-corrosion paint before leaving the factory.

[0074] Some other embodiments of the present invention provide a design method for a structure for preventing the corrosion of the foundation soil of the pile connection joint of the cooling tower PHC pile, which is used to design the structure for preventing the corrosion of the foundation soil of the pile connection joint of the cooling tower PHC pile as described in any of the above embodiments, as Figure 5 shown, the design method includes steps S1 - S3.

[0075] S1. Determine the structural parameters and total quantity of PHC piles according to the structural characteristics and load distribution characteristics of the cooling tower. The structural parameters include the type, diameter, wall thickness, length, and the number of pile splicing joints of the PHC piles. Specifically, the structural characteristics and load distribution characteristics of the cooling tower include those of the ventilation cylinder, water spraying packing device, ring foundation, and pool bottom slab. It should be noted that the main purpose in step S1 is to obtain the structural parameters and total quantity of PHC piles. Specifically, the load calculation process can adopt any existing technology and is not the key point of this disclosure, so it will not be elaborated here. In other embodiments, step S1 can also be skipped and the subsequent steps can be directly carried out based on the data of the structural parameters and total quantity of existing PHC piles.

[0076] S2. Calculate the protection area and protection current for the cathodic protection of pile splicing joints according to the structural parameters and total quantity of PHC piles.

[0077] S3. Calculate its grounding resistance, generated current, service life, and the total quantity of sacrificial anodes according to the physical parameters of the sacrificial anodes.

[0078] In the above technical solution, calculating the total protection area and total protection current for the cathodic protection of pile splicing joints according to the structural parameters and total quantity of PHC piles includes:

[0079]

[0080] I = A·S

[0081] where S represents the total protection area (m 2 ); S i represents the cathodic protection area (m 2 ) of the pile splicing joint on the i-th PHC pile; n represents the total quantity of PHC piles; A represents the cathodic protection current density, which is determined according to the soil resistivity, with the unit of A / m 2 . When the soil resistivity is between 20 and 50 Ω·m, the current density is taken as 10 - 20 mA / m 2 ; I represents the total protection current.

[0082] In the above technical solution, calculating its grounding resistance, generated current, service life, and the total quantity of sacrificial anodes according to the physical parameters of the sacrificial anodes includes:

[0083] Calculating the grounding resistance of a single sacrificial anode includes:

[0084]

[0085] Wherein, R represents the grounding resistance (Ω) of a single sacrificial anode; ρ represents the soil resistivity (Ω·m); L represents the anode length (m); D1 represents the diameter (m) of the filler pack of the sacrificial anode; L1 represents the length (m) of the filler pack of the sacrificial anode; t represents the distance (m) from the center of the sacrificial anode to the ground; ρ1 represents the resistivity (Ω·m) of the filler of the sacrificial anode; D represents the equivalent diameter (m) of the sacrificial anode;

[0086] Calculating the generating current of a single sacrificial anode includes:

[0087]

[0088] Wherein, I f represents the generating current of a single sacrificial anode; ΔE represents the anode driving potential, which is determined according to the material selection of the sacrificial anode, taking 0.65V for magnesium anodes and 0.25V for zinc anodes;

[0089] Calculating the service life of the sacrificial anode includes:

[0090]

[0091] Wherein, Y represents the service life (years) of the sacrificial anode; Q represents the actual capacitance (A·h / kg) of the sacrificial anode; G represents the mass (kg) of a single sacrificial anode; I m represents the average generating current of a single anode, I m = 0.7I f ; 1 / K represents the anode utilization factor, taking 0.85;

[0092] Calculating the total number of sacrificial anodes includes:

[0093]

[0094] Wherein, N represents the total number of sacrificial anodes; B represents the spare coefficient, taking 2 - 3.

[0095] In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0096] Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A structure for preventing soil corrosion at a joint (31) of a PHC pile (3) of a cooling tower, the cooling tower comprising a pool bottom plate (1) and a ring base (2), the pool bottom plate (1) being provided with a plurality of ground beams (11), a plurality of the PHC piles (3) being connected to the ring base (2) and the ground beams (11) respectively, characterized in that: The structure comprises: The pile joint (31) is used to longitudinally connect the standard section of the PHC pile (3), thereby bearing the load of the ring base (2) and the pool bottom plate (1); A pile top steel end plate (32) is arranged at the end of the PHC pile (3) to form a connection surface, and the pile top steel end plate (32) is electrically connected to a prestressed tendon (33) embedded in the PHC pile (3); A cathode protection conductor (4) is electrically connected to the pile top steel end plate; A cathode protection lead-out line (5) is connected to the plurality of cathode protection conductors (4) and is provided with a lead-out end, through which the current flowing through the connection pile joint (31) is led out to the outside of the cooling tower; An anode cable (6) is arranged around the cooling tower, and the lead-out end of the cathode protection lead-out wire (5) is conductively connected to the anode cable (6); A sacrificial anode (7), wherein a plurality of sacrificial anodes (7) are connected to the anode cable (6) and are used to carry the current flowing through the pile connector (31); wherein the potential value of the sacrificial anode (7) is lower than the potential value of the pile connector (31), and the metal corrosion occurring in the pile connector (31) is replaced by an oxidation reaction.

2. The structure for preventing foundation soil corrosion of the PHC pile (3) joint (31) of a cooling tower according to claim 1, characterized in that: The cathode protection conductor (4) is made of stress-bearing steel bars in the ring base (2) and the ground beam (11).

3. The structure for preventing the corrosion of the foundation soil of the PHC pile (3) joint (31) of the cooling tower according to claim 1 is characterized in that: Also includes: A cathodic protection connection (8) is arranged between the connection surface and the cathodic protection conductor (4) to achieve an electrically conductive connection between the cathodic protection conductor (4) and the pile top steel end plate.

4. The structure for preventing soil corrosion of the foundation of the PHC pile (3) joint (31) of a cooling tower according to claim 1, characterized in that: The current flowing through the pile connection joint (31) is transferred to the sacrificial anode (7) through the pile connection joint (31), the pile top steel end plate (32), the cathodic protection wiring (8), the cathodic protection wire (4), the cathodic protection lead wire (5) and the anode cable (6) in sequence.

5. The structure for preventing foundation soil corrosion of the PHC pile (3) joint (31) of a cooling tower according to claim 1, characterized in that: The cathode protection lead wire (5) is made of galvanized flat steel; And / or, the sacrificial anode (7) is made of a magnesium alloy or a zinc alloy.

6. The structure for preventing the corrosion of the foundation soil of the PHC pile (3) joint (31) of the cooling tower according to claim 1, characterized in that: The anode cable (6) is selected from an existing horizontal grounding grid arranged on the periphery of the cooling tower foundation.

7. A design method for preventing soil corrosion in the foundation of a PHC pile-to-pile joint of a cooling tower, characterized in that: The design method is used to design a structure for preventing soil corrosion of the foundation of a PHC pile-to-pile joint of a cooling tower according to any one of claims 1 to 6, and the design method comprises: According to the structural characteristics and load distribution characteristics of the cooling tower, the structural parameters and total number of PHC piles are determined, wherein the structural parameters include the type, diameter, wall thickness, length and number of pile joints of the PHC piles; Calculate the protection area and protection current of the cathodic protection of the pile joint according to the structural parameters and total number of PHC piles; The grounding resistance, generated current, service life and the total number of sacrificial anodes are calculated based on the physical parameters of the sacrificial anode.

8. The design method of the structure for preventing soil corrosion of the foundation of the PHC pile-to-pile joint of the cooling tower according to claim 7 is characterized in that: The structural characteristics and load distribution characteristics of the cooling tower include the structural characteristics and load distribution characteristics of the ventilator, the water sprinkling filler device, the ring foundation and the water pool bottom plate.

9. The design method of the structure for preventing soil corrosion of the foundation of the PHC pile-to-pile joint of the cooling tower according to claim 7, characterized in that: The total protection area and total protection current of the cathodic protection of the pile joint are calculated according to the structural parameters and total number of PHC piles, including: I=A·S Where S represents the total protected area; S i represents the cathodic protection area of ​​the pile joint on the i-th PHC pile; n represents the total number of PHC piles; A represents the cathodic protection current density, which is determined according to the soil resistivity; I represents the total protection current.

10. The design method of the structure for preventing soil corrosion of the foundation of the PHC pile-to-pile joint of the cooling tower according to claim 9, characterized in that: The method of calculating the grounding resistance, generated current, service life and total number of sacrificial anodes according to the physical parameters of the sacrificial anode includes: Calculate the grounding resistance of a single sacrificial anode, including: Wherein, R represents the grounding resistance of a single sacrificial anode; ρ represents the soil resistivity; L represents the anode length; D1 represents the diameter of the sacrificial anode packing; L1 represents the length of the sacrificial anode packing; t represents the distance from the center of the sacrificial anode to the ground; ρ1 represents the resistivity of the sacrificial anode packing; D represents the equivalent diameter of the sacrificial anode; The current generated by a single sacrificial anode is calculated based on the grounding resistance of the single sacrificial anode, including: Among them, I f It represents the current generated by a single sacrificial anode; ΔE represents the anode driving potential, which is determined by the material of the sacrificial anode; Calculate the service life of the sacrificial anode, including: Where Y represents the service life of the sacrificial anode; Q represents the actual capacitance of the sacrificial anode; G represents the mass of a single sacrificial anode; I m Indicates the average current generated by a single anode, I m =0.7I f ; 1 / K represents the anode utilization coefficient; Calculate the total number of sacrificial anodes, including: Wherein, N represents the total number of sacrificial anodes; B represents the backup factor.

Images