Drainage gallery structure of power plant and construction method

Abstract

The invention discloses a drainage gallery structure of a power plant and a construction method, which can improve the construction quality and the construction efficiency of a drainage gallery, avoid the leakage of the drainage gallery at a structural joint caused by differential settlement of a foundation, and ensure the normal operation of the power plant. The drainage gallery structure comprises a drainage pipe and a compensator which are wrapped in a main body structure, the compensator comprises a sleeve and an elastic plugging structure, the drainage pipe is communicated with a maintenance water-collecting well and a permeation water-collecting well, the sleeve is arranged on the drainage pipe in a sleeving mode and is sealed through an elastic sealing structure, and a structural joint is formed in the main body structure. The sleeve is arranged at the position of the structural joint and spans the structural joint; the construction method comprises the steps that a drainage gallery structure is designed, finite element analysis is conducted on the drainage gallery at a structural joint, a drainage pipe is arranged at the preset construction position of the drainage gallery, a sleeve is arranged at the position, corresponding to the structural joint, of the drainage pipe, the drainage pipe and the sleeve are repeatedly constructed, and concrete is poured to form a main body structure. And coating the drain pipe and the sleeve with the main body structure, and the like.

Description

Technical Field

[0001] The invention relates to the technical field of shipping hub engineering, and in particular to a drainage gallery of a power plant and a construction method thereof. Background Art

[0002] In shipping hubs, dams have functions such as improving shipping conditions, flood control, regulating water flow, and storing water for power generation. The drainage corridors of dam power plants are mainly used to remove excess water generated by various factors (such as rainfall, seepage, etc.) inside and outside the dam and power plant, so as to ensure the stability of hydraulic structures, prevent safety hazards, and support power plant operations. The drainage corridors of power plants are usually concrete corridors, which are in the form of culverts. The following problems usually exist during construction and operation: During the construction process, it is usually necessary to erect scaffolding, set up formwork, pour concrete and maintain the work. The erection and dismantling of a large number of formworks are cumbersome and the amount of wet work on site is high. The construction efficiency is low and the project quality is difficult to guarantee.

[0003] During the operation process, due to the limitations of design and construction requirements, structural joints need to be set up in the foundation. Structural joints have inherent settlement and expansion and contraction deformation characteristics. The foundation may settle unevenly due to geological conditions or large differences in the weight of adjacent blocks, which will affect the service life of the concrete corridor. It will also affect the water-stopping equipment, causing cracks in the water-stopping parts, causing leakage in the structural joints, and affecting the normal operation of the power plant. Summary of the invention

[0004] At least one of the purposes of the present invention is to provide a drainage corridor and construction method for a power plant building in order to overcome the problems existing in the above-mentioned prior art, so as to improve the construction quality and construction efficiency of the drainage corridor, avoid leakage of the drainage corridor at the structural joints caused by uneven settlement of the foundation, and ensure the normal operation of the power plant building.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention includes the following aspects.

[0006] A drainage gallery structure of a power plant comprises: a drainage pipe and a compensator, the compensator comprises a casing and an elastic sealing structure, one end of the drainage pipe is connected to a maintenance water collection well, and the other end is connected to an infiltration water collection well, the casing is sleeved on the drainage pipe, and the casing is sealed by an elastic sealing structure, the drainage pipe and the casing are both covered in a main structure, a structural seam is provided on the main structure, the drainage pipe passes through the structural seam, and the casing is arranged at the position of the structural seam and crosses the structural seam.

[0007] Preferably, the elastic sealing structure includes a first sealing layer, a second sealing layer and a third sealing layer. The first sealing layer is laid on the outer wall of the drain pipe to wrap the drain pipe, and the first sealing layer partially extends into the casing and partially is located outside the casing; the second sealing layer is coated on the surface of the first sealing layer, and the third sealing layer is coated on the surface of the first sealing layer. The third sealing layer adheres to the second sealing layer and is arranged close to the pipe mouth of the casing.

[0008] Preferably, the surface of the drain pipe is further covered with a fourth sealing layer, the fourth sealing layer covers the surface of the third sealing layer, and the fourth sealing layer extends from the pipe opening of the casing toward a direction away from the pipe opening of the casing.

[0009] Preferably, the first sealing layer is made of asphalt and felt, the second sealing layer is made of hemp rope, the third sealing layer is made of asphalt hemp sheets, and the fourth sealing layer is made of asphalt.

[0010] Preferably, the drain pipe is made of steel pipe, and the casing is made of steel pipe; the outer wall of the steel pipe is coated with one or more layers of anti-rust paint, and the outer wall of the drain pipe is also coated with resistant paint, and the resistant paint is coated on the surface of the anti-rust paint.

[0011] The present invention also provides a construction method for a drainage gallery structure of a power plant, comprising the following steps: Step S1, designing a drainage gallery structure of a power plant, wherein the drainage gallery structure adopts the aforementioned drainage gallery structure; Step S2, establishing a drainage corridor model at the structural joint in finite element software, and performing finite element analysis on the drainage corridor at the structural joint to ensure that the drainage corridor structure meets the construction requirements; Step S3, installing a drainage pipe at a preset construction position of the drainage corridor; Step S4, setting a sleeve on the drainage pipe at a position corresponding to the preset structural seam; Step S5, repeating steps S3 and S4, so that the drainage pipe is connected to the maintenance water collection well and the infiltration water collection well; Step S6: pouring concrete to form a main structure, so that the main structure covers the drainage pipe and the casing to form a drainage corridor.

[0012] Preferably, in step S1, the process of designing the drainage gallery structure of the power plant includes: Determine the material of the drainage pipe in combination with the main structure, geological conditions, hydrological conditions and construction efficiency of the drainage corridor setting area; Analyze the damage risk faced by drainage pipes buried in the main structure based on the rigor and logic of engineering practice; Design compensation mechanisms based on the material properties of the drain pipe and the damage risk faced by the drain pipe; Design the drainage corridor structure in combination with the compensation mechanism.

[0013] Preferably, when performing finite element analysis on the drainage corridor at the structural joint, a pipeline model is established using solid units in the Ansys Workbench DM interface; when setting boundary conditions, an anisotropic hexahedral meshing method is used to divide the mesh, and the set boundary conditions include the size of the pipeline model and the type of applied load; The pipeline model dimensions include: pipeline outer diameter D O 、Wall thickness D t and the length of the pipe section, L; The applied load types include: applying a gravity load to the overall pipeline model to simulate the deadweight of the soil and the pipeline, applying a displacement load to the bottom of one end of the pipeline model to simulate the underground settlement effect, and using the side of the other end of the pipeline model as a fixed constraint to stabilize the foundation.

[0014] Preferably, in step S4, when the drain pipe is connected to the structural seam position, an elastic sealing structure is arranged at the connection position between the drain pipe and the casing, and the casing and the drain pipe are connected by the elastic sealing structure. After the connection, heated asphalt is respectively laid at the elastic sealing structures at both ends of the casing to form a fourth sealing layer. The fourth sealing layer is arranged on the surface of the drain pipe and extends from the pipe mouth of the casing to a direction away from the pipe mouth of the casing. The laying length of the fourth sealing layer is 2 to 3 m.

[0015] Preferably, on the drain pipe, the elastic sealing structure is symmetrically arranged relative to the structural seam. When the elastic sealing structure is arranged, heated asphalt is laid on the surface of the drain pipe at the preset connection position between the drain pipe and the casing. After the drain pipe is wrapped with the asphalt, one or more layers of felt are pasted on the surface of the asphalt to completely wrap the asphalt to form a first sealing layer; after the first sealing layer is set, hemp rope is embedded on the surface of the first sealing layer, and the hemp rope forms a cross or mesh structure on the surface of the first sealing layer, thereby forming a second sealing layer; then asphalt hemp sheets are wrapped on the surface of the first sealing layer to form a third sealing layer, and the asphalt hemp sheets are arranged in contact with the end face of the second sealing layer and in the direction of the casing pipe mouth, and the wrapping thickness of the asphalt hemp sheets is the same as the thickness of the second sealing layer.

[0016] In summary, due to the adoption of the above technical solution, the present invention has at least the following beneficial effects: The drainage gallery structure of the present invention can compensate for the settlement and shrinkage of the drainage pipe by arranging a sleeve at the position where the drainage pipe passes through the settlement joint, significantly alleviating the stress and strain of the drainage pipe caused by load concentration and the expansion and contraction changes caused by the external environment, making up for the potential defects in the drainage gallery structure, and effectively avoiding the occurrence of drainage pipe leakage at the structural joint; compared with the traditional concrete drainage gallery, the drainage pipe and the sleeve play a dual protection role. Even if the drainage pipe fails partially or under special working conditions, the concrete channel in the main structure can still maintain the function of the drainage gallery, ensuring the stable operation of the drainage gallery and avoiding larger-scale damage due to local problems.

[0017] The drainage pipe is made of steel pipe and can be quickly connected at the construction site. Compared with the traditional concrete drainage corridor construction, the construction method of the present invention not only reduces the amount of wet work on site, avoids the tedious processes such as formwork erection, concrete pouring and maintenance in traditional concrete construction, but also significantly improves the construction efficiency and project quality, and reduces construction and maintenance costs. Before the drainage pipe is installed, finite element analysis of the drainage corridor structure can optimize the drainage corridor structure according to the specific construction conditions to ensure that the drainage corridor structure meets the construction requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a longitudinal sectional view of a drainage gallery structure of a power plant building according to an exemplary embodiment of the present invention.

[0019] Figure 2 It is a cross-sectional view of a drainage gallery structure of a power plant building according to an exemplary embodiment of the present invention.

[0020] Figure 3 It is a flow chart of a construction method of a drainage gallery structure of a power plant building according to an exemplary embodiment of the present invention.

[0021] Figure 4 is an oblique cross-sectional view of a finite element pipeline model of an exemplary embodiment of the present invention.

[0022] Figure 5 It is the stress cloud diagram of settlement joints in concrete drainage corridor.

[0023] Figure 6 It is the stress cloud diagram of settlement joints in casing drainage gallery.

[0024] Figure 7 It is the strain cloud diagram of settlement joints in concrete drainage corridor.

[0025] Figure 8 It is the strain cloud diagram of settlement joints in casing drainage gallery.

[0026] Fig. 9 It is the stress curve of settlement joints of concrete drainage gallery and casing drainage gallery.

[0027] Fig.10 It is the strain curve of settlement joints of concrete drainage gallery and casing drainage gallery.

[0028] Fig.11 It is the stress cloud diagram at the center of the casing.

[0029] Fig.12 It is the stress curve at the center of the steel pipe under different vertical displacement loads.

[0030] Fig.13 It is the stress curve at the center of the casing under different vertical displacement loads.

[0031] Markings in the figure: 1-drain pipe, 2-casing, 3-elastic sealing structure, 31-first sealing layer, 32-second sealing layer, 33-third sealing layer, 34-fourth sealing layer, 4-main structure, 5-structural joint. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments to make the purpose, technical solutions and advantages of the present invention more clearly understood. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] refer to Figure 1 , Figure 2 The drainage corridor of the power plant building of the exemplary embodiment of the present invention includes a drainage pipe 1 and a compensator. One end of the drainage pipe 1 is connected to the maintenance water collection well, and the other end is connected to the infiltration water collection well. The compensator includes a casing 2 and an elastic sealing structure 3. The casing 2 is sleeved on the drainage pipe 1, and the casing 2 is sealed by the elastic sealing structure 3. The drainage pipe 1 and the casing 2 are both covered in a main structure 4. A structural seam 5 is provided on the main structure 4. The drainage pipe 1 passes through the structural seam 5. The casing 2 is arranged at the position of the structural seam 5 and crosses the structural seam 5.

[0034] By arranging a casing 2 on the drainage pipe 1 and making the casing 2 cross the structural seam 5, during the settlement of the structural seam 5, the drainage pipe 1 can be prevented from being deformed due to geological settlement, and leakage of the drainage pipe 1 at the structural seam 5 can be avoided, thereby improving the structural safety and operating stability of the drainage corridor of the power plant.

[0035] There is a certain gap (8~12mm) between the inner wall of the casing 2 and the outer wall of the drainage pipe 1. During the foundation settlement process, the gap between the inner wall of the casing 2 and the outer wall of the drainage pipe 1 can absorb the cracks caused by the foundation settlement and reduce the risk of structural joint penetration. The casing 2 can also optimize the interaction between the drainage pipe 1 and the surrounding medium, and enhance the adaptability of the drainage pipe 1 to external environmental changes (such as soil movement, concrete shrinkage or expansion caused by temperature changes, etc.). Under the action of the casing 2, the axial, lateral and angular displacements caused by thermal expansion and contraction, foundation settlement and other factors can be absorbed.

[0036] The elastic sealing structure 3 includes a first sealing layer 31, a second sealing layer 32 and a third sealing layer 33. The first sealing layer 31 is laid on the outer wall of the drain pipe 1 to wrap the drain pipe 1. The first sealing layer partially extends into the casing 2 and partially is located outside the casing 2. The second sealing layer 32 is coated on the surface of the first sealing layer 31 to seal both ends of the casing 2. The third sealing layer 33 is coated on the surface of the first sealing layer 31. The third sealing layer 33 fits the second sealing layer 32 and is arranged close to the pipe mouth of the casing 2. During the foundation settlement process, the elastic sealing structure 3 can make the casing 2 move axially a certain distance relative to the drain pipe 1, reduce the influence of the foundation misalignment on both sides of the structural seam 5 on the drain pipe, and absorb the axial deformation of the drain pipe 1.

[0037] During the setting process of the sleeve 2, a fourth sealing layer 34 can also be set on the surface of the drain pipe 1. The fourth sealing layer 34 covers the surface of the third sealing layer 33. The fourth sealing layer 34 extends from the pipe mouth of the sleeve 2 in a direction away from the pipe mouth of the sleeve 2. The fourth sealing layer 34 completely covers and compacts the third sealing layer 33, and is tightly combined with the third sealing layer 33 to form a solid sealing structure.

[0038] The first sealing layer 31 is preferably made of asphalt and felt, the second sealing layer 32 is preferably made of hemp rope, the third sealing layer 33 is preferably made of asphalt hemp sheets, and the fourth sealing layer 34 is preferably made of asphalt. The laying length of the fourth sealing layer 34 is 2~3m, and the laying thickness is not greater than the thickness of the second sealing layer 32. In the length direction of the fourth sealing layer 34, the thickness of the fourth sealing layer 34 near the pipe mouth of the casing 2 is thicker than the thickness of other parts to ensure the sealing of the connection between the casing 2 and the drainage pipe 1.

[0039] The drain pipe 1 and the casing 2 are preferably made of steel pipes, which can be efficiently assembled and connected at the construction site, significantly reducing the amount of wet work on site. Compared with the construction of concrete corridors, the complex steps of template erection and removal are avoided, and the construction efficiency and project quality are significantly improved. In addition, the steel pipe material has excellent impermeability, durability and high bearing capacity, which enables it to effectively cope with the variable environmental conditions and load requirements in water conservancy projects, and provide strong support for the long-term stable operation of the drainage corridor. During the application process, the drain pipe 1 can also use other materials with similar or better performance than steel pipes. The outer walls of the drain pipe 1 and the casing 2 are coated with one or more layers of anti-rust paint, and the outer walls of the drain pipe 1 and the casing 2 are also coated with paint-resistant paint, which is coated on the surface of the anti-rust paint to improve the corrosion resistance and high temperature resistance of the drain pipe 1 and the casing 2, and ensure the reliability of the drainage corridor.

[0040] Along the length direction of the drainage pipe 1, a structural seam 5 is set on the main structure 4 around the drainage pipe 1 every 20~25m. When the drainage pipe 1 is set on the foundation, the structural seam 5 on the main structure 4 and the structural seam on the foundation are set correspondingly to prevent the main structure 4 from affecting the settlement and shrinkage of the drainage pipe 1 during the water storage operation. The width of the structural seam 5 is 20~25mm. The structural seam 5 is filled with a polyethylene closed-cell foam board to prevent moisture or other media from penetrating into the structural seam 5, so that the drainage corridor can better adapt to the deformation of the surrounding rock and prevent the occurrence of stress concentration. At the structural seam 5, the length of the casing is 5~8m and the wall thickness is 12mm to improve the adaptability of the drainage pipe 1 to temperature changes and reduce the risk of structural damage to the drainage pipe 1, thereby ensuring the stable operation of the drainage corridor and the safe transportation of water resources; when setting the structural seam 5, it is preferred to set the structural seam 5 at the center of the casing 2 to better disperse the stress.

[0041] refer to Figure 3 The construction method of the drainage gallery structure of the power plant according to the exemplary embodiment of the present invention comprises the following steps: Step S1, designing the drainage corridor structure of the power plant. The process of designing the drainage corridor structure of the power plant specifically includes: The material of the drainage pipe should be determined based on the main structure, geological conditions, hydrological conditions and construction efficiency of the area where the drainage corridor is set up.

[0042] Based on the rigor and logic of engineering practice, the damage risks faced by drainage pipes buried in the main structure are analyzed; the main structure of the drainage corridor is usually a large-volume concrete structure. In the process of constructing the main structure on the surface of the drainage pipe, in order to avoid cracks or crushing of the concrete of the main structure due to volume shrinkage or changes in ambient temperature during the hardening process, structural joints are usually required to control cracks and maintain the integrity of the main structure. When the structural joints pass through the buried drainage pipes, the structural joints may crack or shrink due to thermal expansion and contraction or geological effects, causing the drainage pipes to bear local deformation stress, threatening the structural integrity and functionality of the drainage pipes; the structural joints may also open or shrink to varying degrees due to geological conditions, construction errors or long-term environmental effects, causing radial dislocation deformation of the drainage pipes, which not only affects the continuity and stability of the drainage pipes, but also easily causes fatigue damage or even breakage of the drainage pipes.

[0043] A compensation mechanism is designed based on the material properties of the drainage pipe and the damage risk faced by the drainage pipe. When the drainage pipe is made of steel pipe, the steel pipe has the characteristics of thermal expansion and contraction. The external environment (such as temperature changes) has a significant impact on the drainage pipe. Considering the expansion and contraction compensation mechanism during design can effectively ensure the safety and stability of the drainage corridor structure. When designing the expansion and contraction compensation mechanism, you can consider setting expansion joints, using flexible connectors, optimizing the layout of drainage pipes, etc. to improve the drainage pipe's ability to adapt to temperature changes and reduce the risk of damage to the drainage pipe, thereby ensuring the stable operation of the drainage corridor and the safe transportation of water resources.

[0044] During the operation of the drainage corridor, due to the influence of geological effects, construction factors and long-term loads, the foundation soil is gradually compressed, causing the foundation of the drainage corridor to settle. The settlement compensation mechanism considered in the design can reduce and adapt to the foundation settlement, ensuring that the safety and functionality of the drainage corridor are not affected during use; when designing the settlement compensation mechanism, settlement joints (a type of structural joints) are set at key locations of the drainage corridor (such as the junction of different geological conditions or structural transitions) or at a certain interval to allow the drainage corridor structure to move relatively during settlement to prevent stress concentration; when setting settlement joints, ensure that the settlement joints are well sealed to prevent moisture or other media from penetrating into the settlement joints.

[0045] In combination with the compensation mechanism, a drainage corridor structure is designed; the designed drainage corridor structure adopts the drainage corridor structure of the aforementioned power plant.

[0046] Step S2: Establish a drainage corridor model at the structural joint in finite element software, perform finite element analysis on the drainage corridor at the structural joint, and ensure that the drainage corridor structure meets the construction requirements.

[0047] To facilitate finite element analysis, solid units were used for modeling in the Ansys Workbench DM interface. To simplify the pipeline model, the first sealing layer, the second sealing layer, the third sealing layer and the fourth sealing layer were uniformly represented as asphalt cushion layers. The established model is shown in the figure below. Figure 4 During the finite element analysis, the material parameters defined are shown in Table 1: Table 1 Material parameters name Tensile strength / MPa Shear modulus / GPa Poisson's ratio <![CDATA[Coefficient of linear expansion / 10 -6 *K -1 > Yield strength / MPa Young's modulus / Gpa Steel 375 76.9 0.3 12 235 200 Polyethylene closed cell foam board / 0.39 0.42 / / 1.1 Concrete 2.01 12.71 0.18 10 / 30 When setting the boundary conditions, in order to simplify the meshing process, the anisotropic hexahedral meshing method is used. The specific boundary conditions are set as follows: the outer diameter of the pipe D O 1200mm, wall thickness D t 12mm, pipe length L is 5m, asphalt cushion thickness t is 10mm (when it is a concrete pipe, D O , D t Respectively represent the outer diameter and thickness of the concrete pipe; when it is a sleeve pipe, D O, D t Respectively represent the outer diameter and thickness of the drainage pipe. The thickness of the casing is consistent with the thickness of the drainage pipe. The inner diameter of the casing is the sum of the outer diameter of the drainage pipe and the thickness of the asphalt cushion layer); when applying the load, a gravity load is applied to the overall pipeline model to simulate the deadweight of the soil and the pipeline. A displacement load is applied to the bottom of one end of the pipeline model to simulate the underground settlement effect. The side of the other end of the pipeline model is used as a fixed constraint to stabilize the foundation. By setting the aforementioned boundary conditions, the mechanical behavior and structural response of underground pipelines in complex geological environments can be more realistically simulated, providing reliable theoretical support for the design and construction of underground structures.

[0048] In the pipeline model, one end of the pipeline model is used to simulate the underground settlement effect, and the simulation condition of the other end as the fixed end is a rigid constraint or a displacement-restricted boundary. Under this working condition, gravity, as the main continuous external force, will have a significant impact on the mechanical properties of the structure: gravity not only causes the structure to sink vertically and increases the tensile stress, but also causes stress concentration in weak areas of the structure (such as settlement joints and pipeline connections). These weak areas are prone to become key areas of stress concentration due to differences in material strength, geometric properties and construction quality, and become potential damage risks.

[0049] In order to evaluate the influence of gravity on the drainage corridor structure, especially the stress distribution at the settlement joints and pipe connections, a vertical displacement load was introduced to simulate the deformation and stress response caused by ground settlement or external loads. The initial amplitude of the vertical displacement load was set to 50 mm, and then 10-50 mm was used to analyze the stress conditions at the pipe connections under different load conditions. By extracting stress data, analyzing the stress changes at the settlement joints and pipe connections, and drawing stress intensity cloud maps and distribution curves, the stress change laws at the settlement joints and pipe connections can be clarified, providing reliable data support for optimizing the drainage corridor structure.

[0050] Finite element analysis is performed on the concrete drainage gallery and the sleeve-type drainage gallery of the present invention respectively below to illustrate the advantages of the sleeve-type drainage gallery.

[0051] After establishing the finite element model of the concrete drainage corridor in the same manner as step S5, the same boundary conditions are set for the concrete drainage corridor and the casing drainage corridor, and the same load is applied, to obtain the stress cloud map and strain cloud map of the settlement joint of the concrete drainage corridor (such as Figure 5 , Figure 7 As shown in the figure), stress cloud diagram and strain cloud diagram of the settlement joint of the casing drainage gallery (as shown in the figure), Figure 6 , Figure 8 As shown in the figure), stress curve and strain curve at the settlement joint of concrete drainage gallery and casing drainage gallery (as shown in the figure Fig. 9 , Fig.10 as shown).

[0052] From the stress curve and strain curve, it can be seen that the stress and strain in the upper area of ​​the pipeline centerline are lower than those in the lower area, indicating that there are significant differences in the mechanical response of displacement loads at different positions of the pipeline. Under the same displacement load, the stress and strain of the sleeve drainage gallery at the same position are smaller than those of the concrete drainage gallery, showing better anti-deformation performance. In the 0-1400 mm height range of the path channel, the stress difference between the two drainage galleries is about 10 MPa, indicating that the mechanical properties of the two materials in this section are relatively close; with the increase of height, in the range of 2600-4000 mm, the stress difference gradually decreases from large to small, and the maximum difference is close to 30 MPa, reflecting that in this middle height section, the mechanical response difference between the two drainage galleries is most obvious; near the bottom, the stress of both galleries reaches the maximum value, the stress of the concrete drainage gallery is 124.1 MPa, and the stress of the sleeve drainage gallery is 118.5 MPa, and the stress difference between the two is reduced to 6 MPa. It can be seen that under the action of displacement load, although there are differences in stress distribution between concrete drainage gallery and sleeve drainage gallery, the stress in the bottom area tends to be consistent. In the upper part of the pipe of the sleeve drainage gallery, there is a steep drop in stress. This phenomenon is mainly caused by the discontinuity of the material. In this area, the material transitions from polyethylene closed-cell foam board to steel structure, resulting in a drastic change in material properties, which leads to uneven stress distribution. This structural transition causes the transfer of stress concentration areas and causes a rapid drop in local stress.

[0053] The variation trend of strain with displacement is similar to that of stress. By comparing and analyzing the strain performance of the casing drainage gallery and the concrete drainage gallery under the same displacement load, it is found that the maximum strain values ​​of the two are slightly different. Specifically, the maximum strain of the casing drainage gallery is 0.108 mm, while the maximum strain of the concrete drainage gallery is 0.113 mm.

[0054] Modify the displacement load of the boundary condition to a uniform increase of 10-50mm (e.g., 10mm each time), and obtain a curve of the stress at the top of the steel pipe versus the vertical displacement load (e.g., Fig.12 ) and the curve of the stress at the center of the casing changing with the vertical displacement load (as shown in Fig.13 As shown in the figure), when the vertical displacement load is 50 mm, the non-settlement section (the path of the center line of the steel pipe from the settlement section to the non-settlement section is as shown in the figure) Fig.11The maximum stress value in the settlement section is 248.12MPa, the maximum stress value in the settlement section is 234.64MPa, and the minimum stress value in the center (structural joint) is 8.8MPa; the overall stress distribution trend shows that in the 0-300mm section, there is asphalt cushion contact between the steel pipe and the casing, and the stress rises slowly under the load; when transitioning to the 300-800mm section, there is a gap between the steel pipe and the casing, and the steel pipe is not in direct contact with the casing. In this area, the steel pipe only bears axial force, and the stress concentration phenomenon in other directions is reduced, leading to The stress value is relatively low; in the 800-1000mm section, the stress value begins to drop sharply. The steel pipe may be affected by the bending effect in this area, and the stress concentration of the steel pipe in the non-axial direction is released, further leading to a steep drop in the stress value; when the displacement load is less than 30mm, the stress difference between the settlement section and the non-settlement section is small. When the displacement load reaches 30mm or above, the mean stress of the settlement section begins to be lower than that of the non-settlement section, but the maximum stress of the settlement section is still higher than that of the non-settlement section, showing a significant stress concentration phenomenon in the settlement area under high displacement load.

[0055] refer to Fig.13 , under each displacement load, the stress difference in the settlement section is not large. However, in the 400-600mm range, there is a small stress drop, followed by a sharp rise and drop again. This phenomenon is due to the gap between the casing and the steel pipe, which causes the steel pipe to not completely contact the casing in this section, reducing stress concentration. In the 600-1000mm range, the stress experienced a slow rise and a sharp drop. This change is due to the slight tilt of the steel pipe under the action of the settlement load, and the non-settlement section becomes the main stress area. When the tilt reaches a certain degree, due to the lack of external force compensation, the stress of the structure begins to release, resulting in a decrease in the stress value. This stress change characteristic explains the difference in stress mode between the settlement section and the non-settlement section, and provides a basis for optimal design.

[0056] The stress intensity of the settlement joint and the center area of ​​the steel pipe was evaluated. The results showed that the stress-strain amplitude of the casing concrete drainage corridor at the settlement joint was not much different from that of the concrete drainage corridor, and was even slightly lower by 10%. This shows that the use of steel pipes instead of concrete drainage corridors has a certain enhancement effect on the durability of settlement joints, and the use of casing also has the advantage of anti-seepage; the stress in the center of the casing is higher, indicating that this area is under a large load. However, due to the existence of the casing, it not only provides the necessary structural support, but also effectively compensates for settlement; the casing forms a gap during the load transfer process, which helps to disperse the stress and alleviate the local stress concentration, thereby making up for the shortcomings of the steel pipe structure; the setting of this gap effectively reduces the deformation of the steel pipe in the high stress area. At the same time, the casing allows the pipeline to make a small displacement during the settlement process, thereby preventing rigid damage caused by local settlement; the casing not only improves the mechanical properties of the steel pipe in the stress concentration area, but also improves the stability and anti-settlement ability of the overall structure. It can be seen that the designed drainage gallery structure meets the construction requirements.

[0057] Step S3: installing a drainage pipe at a preset construction position of the drainage corridor.

[0058] The drainage corridor can be set on the foundation, or it can be constructed on the main structure after the construction of part of the main structure. Its specific location is determined according to the design and construction requirements. According to the construction requirements, structural joints (settlement joints) are set on the foundation and the main structure respectively. When settlement joints are set on the foundation, the settlement joints on the foundation and the settlement joints on the main structure are aligned. The drainage pipe uses prefabricated steel pipes. After the drainage pipe is transported to the preset construction position, multiple sections of drainage pipes are connected in sequence according to the design line of the drainage corridor to ensure the sealing of the connection parts of adjacent drainage pipes and prevent pipeline leakage. Before setting the drainage pipe, along the design line direction of the drainage corridor, brackets are evenly set at the bottom of the drainage pipe to avoid contact between the surface of the drainage pipe and the surface of the foundation or the main structure. When the main structure is cast later, the concrete of the main structure can completely cover the drainage pipe; when setting the bracket, adjust the position of the bracket at the design position of the structural joint to facilitate the construction of the casing.

[0059] Step S4: a sleeve is provided on the drainage pipe at a position corresponding to the preset structural seam.

[0060] When the drain pipe is connected to the structural seam, an elastic sealing structure is set at the connection position between the drain pipe and the sleeve, and then the sleeve is passed through the drain pipe, and the sleeve is pushed into the elastic sealing structure, so that the elastic sealing structure blocks the two ends of the sleeve respectively; during the setting process, the sleeve can also be first set on the drain pipe, and after the elastic sealing structure is set on the drain pipe, the sleeve is pushed into the elastic sealing structure, so that the elastic sealing structure blocks the two ends of the sleeve respectively; the sleeve can also be passed through the drain pipe, and then an elastic sealing structure is set on the drain pipe on one side of the structural seam, and after one end of the sleeve is pushed into the elastic sealing structure, the end of the sleeve is separated from the end of the elastic sealing structure by a certain distance, and the sleeve crosses the structural seam, and then another elastic sealing structure is set on the drain pipe on the other side of the structural seam, and the other end of the sleeve is pushed into the corresponding elastic sealing structure, thereby connecting the sleeve and the drain pipe.

[0061] On the drainage pipe, the elastic sealing structure is symmetrically arranged relative to the structural joint. When the elastic sealing structure is arranged, heated asphalt is laid on the surface of the drainage pipe at the preset connection position between the drainage pipe and the casing. After the drainage pipe is wrapped with the asphalt, one or more layers of asphalt felt are pasted on the surface of the asphalt to completely wrap the asphalt to form a first sealing layer. After the asphalt felt wraps the asphalt, during the subsequent construction of the main structure, cement slurry can be prevented from penetrating into the first sealing layer, thereby preventing the first sealing layer from losing its elasticity. After the first sealing layer is arranged, a hemp rope is embedded on the surface of the first sealing layer, and the hemp rope is formed on the surface of the first sealing layer. A cross or mesh structure is formed to form a second sealing layer, and the thickness of the second sealing layer is set to 8-12 mm (preferably 10 mm); when setting the hemp rope, the hemp rope is tightly and evenly arranged on the surface of the first sealing layer to enhance the strength and toughness of the elastic sealing structure; after the second sealing layer is set, asphalt hemp pieces are wrapped on the surface of the first sealing layer to form a third sealing layer, and the asphalt hemp pieces are arranged in contact with the end surface of the second sealing layer and toward the direction of the casing pipe mouth. The wrapping thickness of the asphalt hemp pieces is the same as the thickness of the second sealing layer, and the third sealing layer can further improve the sealing effect on the casing.

[0062] After the casing and the drainage pipe are connected through the elastic sealing structure, heated asphalt is laid on the elastic sealing structures at both ends of the casing to form a fourth sealing layer. The asphalt is laid on the surface of the drainage pipe, extending from the pipe mouth of the casing to the direction away from the pipe mouth of the casing. The laying length of the asphalt is 2~3m.

[0063] Step S5, repeating steps S3 and S4, so that the drainage pipe is connected to the maintenance water collection well and the infiltration water collection well.

[0064] Step S6, pouring concrete to form the main structure, so that the main structure covers the drainage pipe and the casing to form a drainage corridor. During the pouring of concrete, since the main structure is a large-volume concrete structure, the concrete is poured in layers, and a structural joint is set every 20-25m along the direction of the drainage pipe, and a polyethylene closed-cell foam board is filled in the structural joint to prevent uneven settlement of the foundation from causing damage to the main structure.

[0065] The above is only a detailed description of the specific implementation of the present invention, rather than a limitation of the present invention. Various substitutions, modifications and improvements made by those skilled in the relevant art without departing from the principle and scope of the present invention should be included in the protection scope of the present invention.

Claims

1. A drainage gallery structure of a power plant, characterized in that: include: A drain pipe and a compensator, wherein the compensator comprises a sleeve and an elastic sealing structure, one end of the drain pipe is connected to a maintenance water collection well, and the other end is connected to an infiltration water collection well, the sleeve is sleeved on the drain pipe, and the sleeve is sealed by an elastic sealing structure, the drain pipe and the sleeve are both wrapped in a main structure, a structural seam is provided on the main structure, the drain pipe passes through the structural seam, and the sleeve is provided at the position of the structural seam and crosses the structural seam.

2. The drainage gallery structure according to claim 1, characterized in that: The elastic sealing structure includes a first sealing layer, a second sealing layer and a third sealing layer. The first sealing layer is laid on the outer wall of the drain pipe to wrap the drain pipe. The first sealing layer partially extends into the casing and partially is located outside the casing. The second sealing layer is coated on the surface of the first sealing layer. The third sealing layer is coated on the surface of the first sealing layer. The third sealing layer adheres to the second sealing layer and is arranged close to the pipe mouth of the casing.

3. The drainage gallery structure according to claim 2, characterized in that: The surface of the drain pipe is also covered with a fourth sealing layer, the fourth sealing layer covers the surface of the third sealing layer, and the fourth sealing layer extends from the pipe opening of the sleeve to a direction away from the pipe opening of the sleeve.

4. The drainage gallery structure according to claim 3, characterized in that: The first sealing layer is made of asphalt and asphalt felt, the second sealing layer is made of hemp rope, the third sealing layer is made of asphalt hemp sheets, and the fourth sealing layer is made of asphalt.

5. The drainage gallery structure according to any one of claims 1 to 4, characterized in that: The drain pipe is made of steel pipe, and the casing is made of steel pipe; the outer wall of the steel pipe is coated with one or more layers of anti-rust paint, and the outer wall of the drain pipe is also coated with resistant paint, and the resistant paint is coated on the surface of the anti-rust paint.

6. A construction method for a drainage gallery structure of a power plant, characterized in that: The following steps are involved: Step S1, designing a drainage gallery structure of a power plant, wherein the drainage gallery structure adopts the drainage gallery structure as described in any one of claims 1 to 5; Step S2, establishing a drainage corridor model at the structural joint in finite element software, and performing finite element analysis on the drainage corridor at the structural joint to ensure that the drainage corridor structure meets the construction requirements; Step S3, installing a drainage pipe at a preset construction position of the drainage corridor; Step S4, setting a sleeve on the drainage pipe at a position corresponding to the preset structural seam; Step S5, repeating steps S3 and S4, so that the drainage pipe is connected to the maintenance water collection well and the infiltration water collection well; Step S6: pouring concrete to form a main structure, so that the main structure covers the drainage pipe and the casing to form a drainage corridor.

7. The construction method according to claim 6, characterized in that: In step S1, the process of designing the drainage corridor structure of the power plant includes: Determine the material of the drainage pipe in combination with the main structure, geological conditions, hydrological conditions and construction efficiency of the drainage corridor setting area; Based on the rigor and logic of engineering practice, analyze the damage risks faced by drainage pipes buried in the main structure; Design compensation mechanisms based on the material properties of the drain pipe and the damage risk faced by the drain pipe; Design the drainage corridor structure in combination with the compensation mechanism.

8. The construction method according to claim 6, characterized in that: In the step S2, when the drainage corridor at the structural joint is subjected to finite element analysis, a pipeline model is established in the Ansys Workbench DM interface using solid units; when boundary conditions are set, an anisotropic hexahedral meshing method is used to divide the mesh, and the boundary conditions set include the size of the pipeline model and the type of applied load; The pipeline model dimensions include: pipeline outer diameter D O 、Wall thickness D t and the length of the pipe section, L; The applied load types include: applying a gravity load to the overall pipeline model to simulate the deadweight of the soil and the pipeline, applying a displacement load to the bottom of one end of the pipeline model to simulate the underground settlement effect, and using the side of the other end of the pipeline model as a fixed constraint to stabilize the foundation.

9. The construction method according to any one of claims 6 to 8, characterized in that: In step S4, when the drain pipe is connected to the structural seam, an elastic sealing structure is provided at the connection position between the drain pipe and the casing, and the casing and the drain pipe are connected by the elastic sealing structure. After the connection, heated asphalt is respectively laid at the elastic sealing structures at both ends of the casing to form a fourth sealing layer. The fourth sealing layer is arranged on the surface of the drain pipe and extends from the pipe mouth of the casing to a direction away from the pipe mouth of the casing. The laying length of the fourth sealing layer is 2 to 3 m.

10. The construction method according to claim 9, characterized in that: On the drainage pipe, the elastic sealing structure is symmetrically arranged relative to the structural seam. When the elastic sealing structure is arranged, heated asphalt is laid on the surface of the drainage pipe at the preset connection position between the drainage pipe and the casing. After the drainage pipe is wrapped with the asphalt, one or more layers of felt are pasted on the surface of the asphalt to completely wrap the asphalt to form a first sealing layer; after the first sealing layer is arranged, hemp rope is embedded on the surface of the first sealing layer, and the hemp rope forms a cross or mesh structure on the surface of the first sealing layer, thereby forming a second sealing layer; then asphalt hemp sheets are wrapped on the surface of the first sealing layer to form a third sealing layer, and the asphalt hemp sheets are arranged in contact with the end face of the second sealing layer and in the direction of the casing pipe mouth, and the wrapping thickness of the asphalt hemp sheets is the same as the thickness of the second sealing layer.

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