Finite element calculation method and system for water diversion vertical shaft and surge shaft combined arrangement structure of pumped storage power station

Abstract

The invention discloses a pumped storage power station diversion shaft and surge shaft combined arrangement structure finite element calculation method and system, and the method comprises the following steps: a pumped storage power station diversion system shaft and surge shaft combined arrangement model and a pumped storage power station diversion system shaft and surge shaft non-combined arrangement model are established, and the models comprise a turning pipe, a surge shaft shaft, an overlying rock mass and the like; selecting a proper material for the model, dividing model grids and determining calculation coordinates, and then determining calculation boundary conditions according to the working condition of the surge shaft; the stress conditions of linings of the diversion shaft and the surge shaft in different arrangement forms are researched by adopting an elastic theory and combining a finite element analysis method, and the stress rule of the joint of the turning section and the connecting pipe is disclosed. And according to a calculation result, carrying out surge shaft lining shape optimization design. The finite element calculation and optimization analysis method of the diversion shaft and surge shaft combined arrangement structure serves as a reference for optimization design of the surge shaft body type of the pumped storage power station diversion shaft and surge shaft combined arrangement.

Description

Technical Field

[0001] This invention relates to the field of pumped storage power station engineering technology, and in particular to a finite element calculation method and system for the combined arrangement of water intake shaft and surge tank in a pumped storage power station. Background Technology

[0002] The combined arrangement of the intake shaft and surge tank in a pumped storage power station integrates the surge tank and the pressure pipeline shaft. This arrangement can effectively shorten the construction period, reduce tunnel diameter changes, and improve project efficiency. Currently, there are few engineering examples of pumped storage power stations with combined intake shaft and surge tank arrangements, and the power station scale is relatively small. There is a lack of systematic theoretical research on the mechanical properties and optimization of the combined area, and there are very few cases available for reference.

[0003] Compared with the conventional arrangement, the combined arrangement of the water intake shaft and the surge tank of a pumped storage power station has a more special flow channel layout. The combined arrangement of the water intake shaft and the surge tank of a pumped storage power station has the following characteristics: (1) Special local flow channel layout. The combined arrangement of the water intake shaft and the surge tank of a pumped storage power station is carried out in the upper bend section, so that the shafts "become one", which makes the connecting pipe directly connected to the bend section. (2) Complex flow field. Pumped storage power stations have turbine operating conditions and pump operating conditions, and there are two completely different flow states for power generation and pumping. At the same time, during the transition process of different operating conditions of the unit, due to different operating conditions such as load increase and decrease and load shedding, the flow field of water in the surge tank and the bottom flow channel is more complex, and problems such as water hammer reflection and transmission, surge tank water level fluctuation and surge extreme value are more prominent. (3) Complex structural stress. The combination of the water intake shaft and surge tank in a pumped storage power station integrates the connecting pipe with the bend section, making the structure more complex than that of a typical surge tank connecting pipe. Furthermore, due to the asymmetrical shape, the structure may experience localized stress concentration, resulting in a more complex overall structural stress.

[0004] Previous three-dimensional finite element structural analysis of surge tanks focused on the impedance hole structure or the branch pipe at the bottom of the surge tank. However, for surge tanks in pumped storage power stations where the vertical shaft and surge tank are combined, the focus is on the connection between the bend and the connecting pipe. There is a lack of systematic theoretical research on the structural stress of the lining at the connection point. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a finite element calculation method and system for the combined arrangement of water intake shafts and surge tanks in pumped storage power stations, addressing the shortcomings of existing technologies.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a finite element calculation method for the combined arrangement of water intake shaft and surge tank in a pumped storage power station, comprising the following steps:

[0007] S1. Establish a combined layout model and a non-combined layout model of the water intake system vertical shaft and surge tank of a pumped storage power station.

[0008] S2. Select materials for the model, divide the model mesh and establish calculation coordinates, and determine the calculation boundary conditions based on the working conditions of the surge tank; the model includes both layout models and non-layout models.

[0009] S3. Based on the calculated boundary conditions, the stress conditions of the water diversion shaft and surge tank lining under different layout forms are studied using elastic theory and combined with finite element analysis method, revealing the stress law at the connection between the bend section and the connecting pipe.

[0010] S4. Optimize the design of the lining shape of the pressure regulating well by utilizing the stress conditions and stress laws described above.

[0011] In the combined arrangement model, the vertical shaft of the water diversion system and the surge tank are combined, that is, the turning section of the water diversion system is combined with the connecting pipe of the surge tank; in the non-combined arrangement model, the center line of the surge tank is shifted along the water diversion tunnel by a set distance and arranged separately from the turning section.

[0012] In step S2, the specific implementation process of dividing the model mesh and establishing the calculation coordinates includes: generating calculation models with different numbers of meshes under the same geometric model and boundary conditions; performing finite element calculations on each model with different numbers of meshes to obtain the corresponding calculation results; comparing and analyzing the calculation results of different mesh number schemes; and completing the mesh division when the calculation results converge and tend to stabilize as the number of meshes increases.

[0013] In step S2, the specific implementation process of determining the calculation boundary conditions based on the working conditions of the surge tank includes: the surrounding rock range of the calculation model is taken as 5 times the tunnel diameter, and normal constraints are applied to the entire perimeter. The external water pressure and surrounding rock pressure act on the outer surface of the lining, and the internal water pressure acts on the inner surface of the lining. During the operation of the surge tank, the partial factors of the surrounding rock pressure and external water pressure are set to 0, and the load combination only bears the internal water pressure, which is taken as the sum of the water pressure corresponding to the highest surge water level in the one-dimensional transition process calculation and the maximum pressure head rise value at the bottom of the surge tank. During the maintenance period of the surge tank, the surge tank is in an empty maintenance state, the internal water pressure is 0, and the load combination is the external water pressure and the surrounding rock pressure. The external water pressure and the horizontal force of the surrounding rock act on the outer surface of the sprayed layer, and the vertical force of the surrounding rock acts on the horizontal section of the sprayed layer. The calculation model includes a combined layout calculation model and a non-combined layout calculation model.

[0014] The specific implementation process of step S4 includes:

[0015] Concrete spray layer thickness optimization: Based on the actual thickness of the spray layer, plate and shell elements are formed. The thickness of the concrete spray layer is increased and decreased based on the actual thickness to form multiple comparison schemes with different thicknesses. For each thickness scheme, the stress calculation is re-performed using finite element analysis software. The stress and strain of concrete spray layers with different thicknesses are analyzed under the same boundary conditions. The calculation results of different thickness schemes are compared to find out the influence law of the change of concrete spray layer thickness on the stress of the surge tank structure and determine the optimal concrete spray layer thickness.

[0016] Optimization of the position of the bottom plate of the surge tank lining: The position of the bottom plate of the surge tank lining was changed, and the lining was moved to the top of the turning section and the middle of the turning section respectively. The finite element analysis method was used to calculate the stress distribution and strain of each scheme after adjusting the bottom plate position. The stress results of different bottom plate position schemes were compared to study the influence of the bottom plate position change on the lining stress and determine the optimal bottom plate position that makes the surge tank structure reasonably and uniformly stressed and meets the design requirements.

[0017] As an inventive concept, the present invention also provides a finite element calculation system for the combined arrangement of water intake shaft and surge tank of a pumped storage power station, including a memory, a processor and a computer program stored in the memory; the processor executes the computer program to implement the steps of the above method.

[0018] As an inventive concept, the present invention also provides a terminal device, including a memory, a processor, and a computer program stored in the memory; characterized in that the processor executes the computer program to implement the steps of the above method.

[0019] As an inventive concept, the present invention also provides a computer-readable storage medium having a computer program / instructions stored thereon; when the computer program / instructions are executed by a processor, they implement the steps of the above-described method.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. This invention adopts a combined arrangement of water intake shaft and surge tank in a pumped storage power station. The stress distribution patterns of the combined and non-combined arrangements under different typical working conditions are compared and analyzed. The stress conditions of the lining under different working conditions are studied, the stress distribution pattern at the connection between the bend section and the connecting pipe is obtained, and the mechanical behavior of different arrangements under different working conditions is explored.

[0022] 2. This invention discloses the stress conditions of the lining of the combined arrangement of water intake shaft and surge tank in a pumped storage power station under different spray layer thicknesses, and studies the influence of the position of the lining bottom plate of the surge tank on the stress of the lining. This provides a reference for the optimized design of the surge tank shape when the water intake shaft and surge tank are combined in a pumped storage power station, and also provides technical support for the construction of pumped storage power stations. Attached Figure Description

[0023] Figure 1 This is a flowchart of the finite element calculation and optimization analysis method for the combined arrangement of water intake shaft and surge tank of a pumped storage power station provided in an embodiment of the present invention;

[0024] Figure 2 The pumped storage power station water intake system vertical shaft and surge tank layout model provided in the embodiments of the present invention are as follows: (a) vertical shaft and surge tank are arranged in combination, and (b) vertical shaft and surge tank are arranged in non-combined combination.

[0025] Figure 3 The following is an overall model of the calculation area of ​​the pumped storage power station provided in the embodiments of the present invention: (a) is the lining calculation model, and (b) is the overall calculation model.

[0026] Figure 4 The calculation model mesh for the combined arrangement of water intake shaft and surge tank in this embodiment of the invention is shown in (a) as a hexahedral lining mesh and (b) as a hexahedral surrounding rock mesh.

[0027] Figure 5 The stress diagrams of the inner wall of the lining at the junction of the turning section and the connecting pipe of the vertical shaft and the surge tank of the water diversion system in this embodiment of the invention are shown in (a) and (b) respectively.

[0028] Figure 6 The stress diagrams of the inner wall of the lining at the junction of the turning section and the connecting pipe in the water diversion system without the vertical shaft and the pressure regulating shaft in the embodiment of the present invention are shown in (a) and (b) respectively.

[0029] Figure 7 The following are stress distribution diagrams at the junction of the bend section and the connecting pipe with different spray layer thicknesses in the embodiments of the present invention: (a) stress on the inner wall of the 20cm spray layer lining during operation, (b) stress on the inner wall of the 40cm spray layer lining during operation, (c) stress on the inner wall of the 20cm spray layer lining during maintenance, and (d) stress on the inner wall of the 40cm spray layer lining during maintenance.

[0030] Figure 8The following are the stress distribution diagrams of the lining at different positions of the bottom plate of the pressure regulating well in the embodiments of the present invention: (a) stress of the inner wall of the lining with a 20cm spray layer during operation, (b) stress of the inner wall of the lining with a 40cm spray layer during operation, (c) stress of the inner wall of the lining with a 20cm spray layer during maintenance, and (d) stress of the inner wall of the lining with a 40cm spray layer during maintenance. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] Embodiment 1 of the present invention provides a structural calculation method for a pumped storage power station with a combined arrangement of vertical shafts and surge tanks in its water intake system. The method includes steps S1-S4, such as... Figure 1 As shown, the details are as follows:

[0034] S1 establishes a combined layout model and a non-combined layout model of the water intake system shafts and surge tanks of the pumped storage power station. The model includes turning pipes, surge tank shafts, and overlying rock mass.

[0035] S2 involves selecting suitable materials for the model established in step S1, dividing the model mesh, and establishing the calculation coordinates. Then, the calculation boundary conditions are determined based on the working conditions of the surge tank.

[0036] Based on S2, S3 uses elasticity theory and finite element analysis to study the stress conditions of the lining of the water intake shaft and surge tank under different layout forms, revealing the stress law at the connection between the bend section and the connecting pipe.

[0037] S4. Based on the calculation results in step S3, optimize the design of the surge tank lining shape. Specifically, study the influence of the concrete spray layer thickness on the stress of the surge tank structure, and study the influence of the position of the lining bottom plate of the surge tank on the stress of the lining.

[0038] More preferably, in step S1, the three-dimensional model is constructed as follows:

[0039] Based on the design plan, professional 3D modeling software was used to create an overall model containing the turning pipe, surge tank shaft, and overlying rock mass for simulation calculations. The surrounding rock mass was taken as 5 times the tunnel diameter. The water diversion system shaft and surge tank are arranged in combination, meaning the turning section of the water diversion system is connected to the surge tank shaft. If they are not combined, the centerline of the surge tank is simply shifted a certain distance along the water diversion tunnel and arranged separately from the turning section.

[0040] More preferably, in step S2, the model material properties, mesh generation, and calculated coordinates are performed as follows:

[0041] The overall model of the coexisting bend pipe, surge tank shaft, and overlying rock mass uses three materials: C30 concrete, C25 concrete, and surrounding rock. These three materials interact with each other in the coexisting model, jointly bearing the mechanical properties and stability of the structure.

[0042] The computational mesh was entirely generated using hexahedral meshes, with mesh refinement applied to complex local areas. Mesh correlation was checked, taking into account computational accuracy, cost-effectiveness, and computation time. The specific implementation process is as follows: A mesh correlation evaluation index was selected, such as the maximum stress value at the exit section of the turning segment during operation. Under the same geometric model and boundary conditions, computational models with different mesh counts were generated. Finite element analysis was performed on each model with different mesh counts, yielding the corresponding calculation results. The calculation results of different mesh count schemes were compared and analyzed to observe the trend of changes in the calculation results as the mesh count increased. When the calculation results (such as the maximum stress value) gradually converged and stabilized with the increase of the mesh count, it indicated that the mesh generation at this point met the computational accuracy requirements.

[0043] The overall 3D model adopts a Descartes rectangular coordinate system. The X-axis extends along the axis of the water diversion tunnel, pointing towards the upstream reservoir, with positive. The Y-axis extends vertically, pointing towards the pressure pipeline shaft, with positive upwards. The Z-axis is determined using the right-hand rule. The origin of the coordinate system is located at the center of the bottom plate of the surge tank.

[0044] More preferably, in step S2, the operation of the pressure regulating well is carried out according to the following method:

[0045] According to NB / T10391—2020 "Code for Design of Hydraulic Tunnels", and considering the actual working conditions of the surge tank above the connection point, the design conditions are divided into permanent and temporary conditions. Based on different stress conditions, the most unfavorable load combination is considered as the load condition for the calculation. The permanent condition corresponds to the limit state (operation period) of normal use of the surge tank, while the temporary condition corresponds to the surge tank venting and maintenance state (maintenance period).

[0046] More preferably, in step S2, the boundary conditions are set according to the following steps:

[0047] The calculation model uses a surrounding rock area of ​​5 times the tunnel diameter, with normal constraints applied to the entire perimeter. External water pressure and surrounding rock pressure act on the outer surface of the lining, while internal water pressure acts on the inner surface. During operation, external pressure is a favorable load for the surge tank. To select the most unfavorable load conditions, the partial factors for surrounding rock pressure and external water pressure are set to 0. The load combination only bears the internal water pressure, which is taken as the sum of the highest surge water level calculated during the one-dimensional transient process and the maximum pressure rise at the bottom of the surge tank. During maintenance, the surge tank is in an emptied maintenance state, with internal water pressure at 0. The load combination consists of external water pressure and surrounding rock pressure. The external water pressure and the horizontal force of the surrounding rock act on the outer surface of the sprayed layer, while the vertical force of the surrounding rock acts on the horizontal section of the sprayed layer.

[0048] More preferably, in step S2, the load action coefficient is selected according to the following steps:

[0049] The action coefficients of different external loads vary under different working conditions and stress states of the lining.

[0050] (1) Surrounding rock pressure

[0051] When the surge tank is under maintenance, the partial factor for the load is 1.0. The surrounding rock pressure is applied as the maximum principal stress to the outside of the lining. Under normal operating conditions, it is a favorable load. Taking the most unfavorable case, the effect of the surrounding rock pressure on the lining is ignored, and the partial factor for the load is taken as 0.

[0052] (2) Internal water pressure

[0053] According to the provisions of NB / T11011-2022 "Code for Design of Hydraulic Concrete Structures", when using the linear elastic analysis method to calculate the ultimate limit state of the bearing capacity of reinforced concrete structures, the standard value of permanent action is taken by multiplying γ0ΨγG, and the standard value of variable action is taken by multiplying γ0ΨγQ.

[0054] (3) External water pressure

[0055] The external water pressure value needs to be multiplied by the corresponding reduction factor according to the surrounding rock type. Under normal operating conditions, it is a favorable load, and the load partial factor is taken as 0. Under maintenance conditions, it is an unfavorable load, and the load partial factor is taken as 1.0.

[0056] More preferably, in step S3, the elasticity theory is performed as follows:

[0057] The fundamental equations of elasticity include geometric equations, equilibrium differential equations, deformation compatibility equations, and physical equations.

[0058] (1) Geometric equations

[0059]

[0060] in, It represents the normal strain component in a certain direction; Let be the shear strain component in a certain direction. It represents the displacement of a point along the x, y, and z coordinate directions.

[0061] Further, integrating, we get:

[0062]

[0063] in, is the integration constant.

[0064] (2) Equilibrium differential equation:

[0065]

[0066] in, This represents the components of the force per unit volume in the X, Y, and Z directions. For normal stress in a certain direction, This represents the shear stress in a certain direction.

[0067] (3) Deformation compatibility equation

[0068] The deformation compatibility equation describes the continuity of an elastic body under external force loads and is derived from geometric equations.

[0069]

[0070] in, For the normal strain in a certain direction, Let be the shear strain in a certain direction.

[0071] (4) Physical equations:

[0072] For an elastic body, if it is isotropic, then the linear relationship between its stress and strain satisfies the generalized Hooke's law, i.e.

[0073]

[0074] Where E is the elastic modulus; G is Poisson's ratio; G is the shear modulus, where... .

[0075] More preferably, in step S4, the optimized design of the surge tank lining shape is obtained according to the following steps:

[0076] Concrete spraying thickness optimization: Shell elements were created based on the actual thickness of the spraying layer. Then, the concrete spraying thickness was increased and decreased based on the actual thickness, resulting in several comparative schemes with different thicknesses. For each thickness scheme, finite element analysis software was used to recalculate the stress, strain, and other characteristics of the concrete spraying layer with different thicknesses under the same boundary conditions. By comparing the calculation results of different thickness schemes, the influence of variations in concrete spraying thickness on the stress of the surge tank structure was identified, and the optimal concrete spraying thickness was determined.

[0077] Optimization of the position of the bottom plate of the surge tank lining: The position of the bottom plate of the surge tank lining was changed, moving it to above the bend section and the middle of the bend section respectively. Finite element analysis was used to calculate the stress distribution and strain of each scheme after adjusting the bottom plate position. The stress results of different bottom plate position schemes were compared to study the impact of the bottom plate position change on the lining stress, and the optimal bottom plate position was determined to make the surge tank structure more rationally and uniformly stressed and meet the design requirements.

[0078] The invention will be further illustrated below with specific embodiments. Taking a pumped-storage power station with a combination of vertical shafts and surge tanks in a water diversion system as an example, the method of the invention will be described in detail. Basic power station data: surge tank bottom elevation 579.0m, inlet bottom elevation 594.0m, surge tank diameter 16m, pipe diameter 9.5m, turning radius 10m, connecting pipe diameter 5m. The surge tank lining calculation model and overall calculation model are established as follows: Figure 1 As shown.

[0079] The overall model of the coexistence of the turning pipe, the pressure regulating shaft, and the overlying rock mass uses three materials: C30 concrete, C25 concrete, and surrounding rock. The performance parameters of each material are shown in Table 1-2.

[0080] Table 1 Concrete material parameters

[0081]

[0082] Table 2. Parameters used in the physical and mechanical calculations of the surrounding rock.

[0083]

[0084] right Figure 1 The model was meshed, with four different mesh sizes designed. The maximum stress at the exit section of the turning segment during operation was used as the mesh correlation verification index. The calculation results for the four mesh size schemes are shown in Table 3. Considering computational accuracy, economy, and cycle time, a total of 872,631 meshes were determined.

[0085] Table 3 Comparison of maximum stress during operation at the exit section of the turning segment with different grid numbers

[0086]

[0087] The overall 3D model adopts a Descartes rectangular coordinate system. The X-axis extends along the axis of the water diversion tunnel, pointing towards the upstream reservoir, with positive. The Y-axis extends vertically, pointing towards the pressure pipeline shaft, with positive upwards. The Z-axis is determined using the right-hand rule. The origin of the coordinate system is located at the center of the bottom plate of the surge tank.

[0088] The loads of each main control section of the load-bearing water conveyance system are shown in Table 4.

[0089] Table 4 Loads at major control sections of the water conveyance system

[0090]

[0091] The values ​​for each load action factor are specified as follows:

[0092] (1) Surrounding rock pressure

[0093] The partial factor for load action is 1.0. Under normal operating conditions, the load is a favorable load, and the partial factor for load action is 0.

[0094] (2) Internal water pressure

[0095] According to the provisions of NB / T11011-2022 "Code for Design of Hydraulic Concrete Structures", when using the linear elastic analysis method to calculate the ultimate limit state of the bearing capacity of reinforced concrete structures, the standard value of permanent action is taken by multiplying γ0ΨγG, and the standard value of variable action is taken by multiplying γ0ΨγQ.

[0096] (3) External water pressure

[0097] The external water pressure value needs to be multiplied by the corresponding reduction factor according to the surrounding rock type. Under normal operating conditions, it is a favorable load, and the load partial factor is taken as 0; under maintenance conditions, it is an unfavorable load, and the load partial factor is taken as 1.0.

[0098] External water pressure and surrounding rock pressure act on the outer surface of the lining, while internal water pressure acts on the inner surface. In the calculation results, the stress in the concrete lining and surrounding rock is represented by tensile stress as positive and compressive stress as negative, with units of MPa; the displacement components are represented by the positive direction along the coordinate axis, with units of m.

[0099] According to NB / T10391—2020 "Code for Design of Hydraulic Tunnels", and considering the actual working conditions of the surge tank above the connection point, the design conditions are divided into permanent and temporary conditions. The limit state for normal use of the surge tank is designed according to the permanent condition, and the most unfavorable load combination is used as the calculation condition. Two typical working conditions are selected for calculation based on different stress conditions.

[0100] Operating Condition 1: Operation Period (Peak Surge)

[0101] This working condition is a favorable external pressure condition. In order to select the most unfavorable load conditions, the partial factors for the surrounding rock pressure and external water pressure are taken as 0, and the surge tank lining is only subjected to the internal water pressure.

[0102] Operating Condition 2: Maintenance Period (Surrounding Rock Pressure + External Water Pressure).

[0103] The surge tank is under maintenance and emptying, with zero internal water pressure. The loads considered in the calculation include external water pressure and surrounding rock pressure. During the maintenance period, it is assumed that the surrounding rock, lining, and shotcrete layer will share the external water pressure.

[0104] Table 5 Load Combinations

[0105]

[0106] The specific boundary conditions are set as shown in Table 5:

[0107] 1. The highest surge load combination during normal operation only involves internal water pressure, which acts on the inner surface of the lining. The value is taken as the highest surge head of 70.78m calculated in the one-dimensional transition process of the surge tank body, plus the maximum pressure rise at the bottom of the surge tank of 15.60m.

[0108] 2. The load combination during the venting and maintenance period consists of external water pressure and surrounding rock pressure. The external water pressure head of 25.65m and the horizontal force of the surrounding rock act on the outer surface of the sprayed layer, while the vertical force of the surrounding rock acts on the horizontal section of the sprayed layer.

[0109] Based on the model and load described above, and combined with the actual working conditions of the surge tank, calculation conditions and load combinations were set. The loads were applied to models with different layouts of water intake shafts and surge tanks. The corresponding stress analysis of the lining during operation and maintenance was carried out using the finite element analysis software ANSYS. The stress conditions of the lining as a whole and local sections were obtained from the analysis.

[0110] In the combined layout of vertical shafts and surge tanks, during operation, under the influence of internal water pressure, the lining tends to deform outwards. The lining stress is predominantly tensile, exhibiting a full-section stress trend, and the tensile stress values ​​are generally high, necessitating the installation of tensile reinforcement to limit crack propagation. During maintenance, the lining is subjected to external water pressure and surrounding rock pressure, resulting in inward deformation and a state of compression. Under the combined influence of external water pressure and surrounding rock pressure, the lining exhibits a full-section compression trend, with generally high compressive stress values, such as... Figure 5 As shown. Figure 6 The results are from a three-dimensional finite element stress analysis of the structure with separate vertical shafts and surge tanks. Overall, the stress on the lining of the separate arrangement is slightly less than that of the combined arrangement.

[0111] During operation and maintenance, the stress-strain distribution diagrams of the lining cross-section at the connection between the bend and the connecting pipe under different sprayed layer thicknesses were consistent with the shape pattern without sprayed layer. When the sprayed layer thickness increased from 0cm to 20cm, the maximum tensile stress during operation decreased by 10.46%; the maximum compressive stress during maintenance decreased by 22.17%. When the sprayed layer thickness further increased from 20cm to 40cm, the maximum tensile stress during operation decreased by 2.83%; the maximum tensile stress during maintenance decreased by 3.00%. After adding the concrete sprayed layer, the maximum tensile stress and maximum compressive stress of the surge tank lining both decreased significantly, and the rate of decrease in maximum stress gradually decreased with the continued increase in sprayed layer thickness. Figure 7 As shown.

[0112] During operation and maintenance, the location of the surge tank bottom lining significantly affects its stress distribution. When the lining is located above the bend, during operation, it is subjected to internal water pressure, with the stress-bearing surface on the inner side, resulting in a maximum tensile stress of 10.288 MPa, an increase of 4.57% compared to when it is located at the bend outlet. During maintenance, it is subjected to external water pressure, with the stress-bearing surface on the outer side. The lining thickness at the connecting pipe decreases, and the stress concentration point shifts to the connection between the connecting pipe and the bend, significantly increasing the maximum stress. When the lining is located in the middle of the bend, the stress distribution and maximum stress-strain of the bend are similar to the initial design during both operation and maintenance. However, a new stress concentration point appears at the connection between the bend and the surge tank bottom lining, with a maximum tensile stress of 10.810 MPa, an increase of 8.98% compared to when it is located at the bend outlet. Therefore, the surge tank bottom lining located at the bend outlet offers relatively better stress distribution. Figure 8 As shown.

[0113] Example 2

[0114] Embodiment 2 of the present invention provides a terminal device corresponding to Embodiment 1 above. The terminal device can be a processing device for a client, such as a mobile phone, a laptop, a tablet computer, a desktop computer, etc., to execute the method of the above embodiments.

[0115] The terminal device in this embodiment includes a memory, a processor, and a computer program stored in the memory; the processor executes the computer program in the memory to implement the steps of the method in Embodiment 1 described above.

[0116] In some implementations, the memory may be high-speed random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage device.

[0117] In other implementations, the processor can be any type of general-purpose processor, such as a central processing unit (CPU) or a digital signal processor (DSP), and there is no limitation here.

[0118] Example 3

[0119] Embodiment 3 of the present invention provides a computer-readable storage medium corresponding to Embodiment 1 above, on which a computer program / instructions are stored. When the computer program / instructions are executed by a processor, they implement the steps of the method of Embodiment 1 above.

[0120] A computer-readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination thereof.

[0121] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0122] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0123] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0124] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0125] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A finite element calculation method for a combined arrangement of a water intake shaft and a surge tank in a pumped storage power station, characterized in that, Includes the following steps: S1. Establish calculation models for the combined and non-combined arrangement of vertical shafts and surge tanks in the water intake system of a pumped storage power station. S2. Select materials for the model, divide the model mesh and establish calculation coordinates, and determine the calculation boundary conditions based on the working conditions of the surge tank; the model includes both layout models and non-layout models. S3. Based on the calculated boundary conditions, the stress conditions of the water diversion shaft and surge tank lining under different layout forms are studied using elastic theory and combined with finite element analysis method, revealing the stress law at the connection between the bend section and the connecting pipe. S4. Optimize the design of the lining shape of the pressure regulating well by utilizing the stress conditions and stress laws described above.

2. The finite element calculation method for the combined arrangement of the water intake shaft and surge tank of a pumped storage power station according to claim 1, characterized in that, In the combined arrangement model, the vertical shaft of the water diversion system and the surge tank are combined, that is, the turning section of the water diversion system is combined with the connecting pipe of the surge tank; in the non-combined arrangement model, the center line of the surge tank is shifted along the water diversion tunnel by a set distance and arranged separately from the turning section.

3. The finite element calculation method for the combined arrangement of water intake shaft and surge tank in a pumped storage power station according to claim 1, characterized in that, In step S2, the specific implementation process of dividing the model mesh and establishing the calculation coordinates includes: generating calculation models with different numbers of meshes under the same geometric model and boundary conditions; performing finite element calculations on each model with different numbers of meshes to obtain the corresponding calculation results; comparing and analyzing the calculation results of different mesh number schemes; when the calculation results converge and tend to stabilize as the number of meshes increases, the required number of meshes for the calculation model is determined, and the mesh division is completed.

4. The finite element calculation method for the combined arrangement of water intake shaft and surge tank in a pumped storage power station according to claim 1, characterized in that, In step S2, based on the number of grids required for the calculation model, the specific implementation process of determining the calculation boundary conditions according to the working conditions of the surge tank includes: the surrounding rock range of the calculation model is taken as 5 times the tunnel diameter, and normal constraints are applied to the entire perimeter. The external water pressure and surrounding rock pressure act on the outer surface of the lining, and the internal water pressure acts on the inner surface of the lining; during the operation period of the surge tank, the partial factors of the surrounding rock pressure and external water pressure are set to 0, and the load combination only bears the internal water pressure, which is taken as the sum of the water pressure corresponding to the highest surge water level in the one-dimensional transition process calculation and the maximum pressure rise at the bottom of the surge tank; during the maintenance period of the surge tank, the surge tank is in an empty maintenance state, the internal water pressure is 0, and the load combination is the external water pressure and surrounding rock pressure; the external water pressure and the horizontal force of the surrounding rock act on the outer surface of the sprayed layer, and the vertical force of the surrounding rock acts on the horizontal section of the sprayed layer; the calculation model includes a combined layout calculation model and a non-combined layout calculation model.

5. The finite element calculation method for the combined arrangement of the water intake shaft and surge tank of a pumped storage power station according to claim 1, characterized in that, The specific implementation process of step S4 includes: Concrete spray layer thickness optimization: Based on the actual thickness of the spray layer, plate and shell elements are formed. The thickness of the concrete spray layer is increased and decreased based on the actual thickness to form multiple comparison schemes with different thicknesses. For each thickness scheme, the stress calculation is re-performed using finite element analysis software. The stress and strain of concrete spray layers with different thicknesses are analyzed under the same boundary conditions. The calculation results of different thickness schemes are compared to find out the influence law of the change of concrete spray layer thickness on the stress of the surge tank structure and determine the optimal concrete spray layer thickness. Optimization of the position of the bottom plate of the surge tank lining: The position of the bottom plate of the surge tank lining was changed, and the lining was moved to the top of the turning section and the middle of the turning section respectively. The finite element analysis method was used to calculate the stress distribution and strain of each scheme after adjusting the bottom plate position. The stress results of different bottom plate position schemes were compared to study the influence of the bottom plate position change on the lining stress and determine the optimal bottom plate position that makes the surge tank structure reasonably and uniformly stressed and meets the design requirements.

6. A finite element calculation system for a combined arrangement of a water intake shaft and a surge tank in a pumped storage power station, comprising a memory, a processor, and a computer program stored in the memory; characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 5.

7. A terminal device, comprising a memory, a processor, and a computer program stored in the memory; characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program / instructions stored thereon; characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method according to any one of claims 1 to 5.

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