Bottom plate partition variable stiffness leveling design method, system and equipment and storage medium

Abstract

The invention discloses a base plate partition variable stiffness leveling design method, system and device and a storage medium. The design method comprises the steps that S1, a calculation model is established; s2, arranging a nonlinear spring; s3, carrying out stiffness iterative calculation; s4, partition variable stiffness adjustment of the bottom plate is carried out; and S5, foundation rigidity compensation. According to the method, the pain point of traditional linear spring hypothesis and conservative design is solved, field in-situ plate load test data are obtained to construct a nonlinear spring model, the foundation rigidity is dynamically matched with the actual stress state, multiple times of rigidity iteration are conducted, the spring rigidity is dynamically adjusted along with sedimentation and counter force till convergence is achieved, it is ensured that the internal force and deformation calculation result is accurate, and the method is suitable for large-scale popularization and application. The rigidity of a high-deformation area is enhanced in a targeted mode and the rigidity of a low-deformation area is weakened according to deformation deviation subareas, meanwhile, a transition area is arranged to avoid sudden rigidity change, deformation is controlled, materials are saved, the area with insufficient bearing capacity is identified through counter-force verification, only foundation treatment or deep foundation design is conducted on a key area, and waste of large-area reinforcement is avoided.

Description

Technical Field

[0001] This invention belongs to the field of water treatment business technology, specifically involving the design method, system, equipment and storage medium for bottom plate partitioning variable stiffness leveling. Background Technology

[0002] With the advancement of urban industrial wastewater treatment and reuse technologies and zero-discharge technologies, the scale of centralized urban sewage treatment is constantly expanding, and the process of integrated transformation of plants, networks, and rivers is accelerating. This has led to an increasing demand for the construction of various large-scale water treatment tanks (such as sedimentation tanks, aeration tanks, and equalization tanks), and their sizes are also constantly increasing. These tanks are typically characterized by large areas and thin bottom slabs. The structural bottom slabs are subjected to complex stresses under conditions such as full water and compartmentalized start-up and shutdown, and are highly sensitive to uneven settlement of the foundation. Therefore, the internal force distribution and deformation control of large structural bottom slabs are becoming a key challenge in water treatment engineering design.

[0003] The water treatment tank structure includes a top slab 11, side walls 12, and a bottom slab 13; the bottom slab 13 is designed with variable stiffness leveling. Currently, common design methods simplify the foundation soil to a Winkler linear spring (i.e., the subgrade coefficient K is constant). Under full load conditions, when calculating the bottom slab structure using uniform linear spring stiffness, the bottom slab will exhibit significant "dish-shaped" settlement (larger inside than outside) and a "saddle-shaped" reaction force distribution (smaller inside than outside) during actual operation. The negative effect of dish-shaped settlement is the additional stress generated in the soil due to non-uniform deformation, which will cause additional bending moment, additional shear force, and even cracking and leakage in the bottom slab structure. The negative effect of the saddle-shaped reaction force distribution is an increase in the overall bending moment of the bottom slab.

[0004] In reality, soil compression is not a constant value, but rather increases non-linearly with the increase of overlying effective pressure. Normally consolidated soil is a strain-hardening material, but existing design methods fail to fully consider this characteristic. Especially under conditions of full water treatment tanks or uneven foundation distribution, uniformly distributed linear springs cannot accurately reflect the distribution of foundation reaction forces, often overestimating settlement in high-stress areas and underestimating settlement in low-stress areas. This leads to significant deviations between the calculated internal forces and deformation distribution of the tank bottom slab structure and the actual situation. To counteract the most unfavorable conditions calculated by existing methods, engineers often adopt conservative design methods such as overall thickening of the bottom slab, large-area foundation reinforcement, or uniform placement of pile foundations within the bottom slab area. This results in large material consumption, high project costs, and poor economic benefits.

[0005] Therefore, it is necessary to research and develop design methods, systems, equipment, and storage media for zonal variable stiffness leveling of the base plate to solve the above problems. Summary of the Invention

[0006] To address the shortcomings in the accuracy of calculating the deformation and internal forces of the base plate in the structural design of various large-scale water treatment tanks in existing technologies, this invention provides a zonal variable stiffness leveling design method for the base plate. Based on in-situ plate load tests and considering the compressibility of the foundation soil, a nonlinear foundation spring is used. Through iterative stiffness calculation, the stiffness of the structural base plate is changed in zonal areas according to the calculation results. At the same time, targeted stiffness compensation is performed on the foundation of the structural base plate, thereby optimizing the engineering design and improving the rationality and economy of the structural design.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] The base plate zoning and stiffness-adjustment design method divides the structural base plate into a stiffness-enhancing zone, a stiffness transition zone, and a stiffness-weakening zone. In the stiffness-enhancing zone, the thickness of the base plate is increased or concealed reinforcing components are installed. In the stiffness-weakening zone, the thickness of the base plate is reduced. The stiffness transition zone is located between the stiffness-enhancing and stiffness-weakening zones. The design method includes the following steps:

[0009] S1. Establish the calculation model: Establish a geometric model of the water treatment tank according to the process requirements and structural dimensions, and assign relevant material parameters to the geometric model of the water treatment tank; divide the structural base plate into equal-width shell element meshes to form a mesh model; assign loads and corresponding boundary conditions to the mesh model according to the working conditions.

[0010] S2. Deploying Nonlinear Springs: Duplicate the base plate element nodes at equal intervals along a direction perpendicular to the structural base plate. Set the replicated nodes as fixed nodes. Deploy nonlinear springs, considering the compressibility of the foundation soil, between the base plate element nodes and the replicated nodes to simulate the interaction between the foundation soil and the structural base plate; specifically:

[0011] S2.1 Obtain the load-settlement correspondence value from the plate load test data in the geological survey report, plot the load-settlement curve, denoted as the p~s curve, and select the pressure p0 and the settlement s0 corresponding to p0 in the linear segment of the p~s curve.

[0012] When there is no straight line segment in the p~s curve, p0 is taken as the ultimate load p of the foundation soil. u Half of p0, where s0 is the settlement amount corresponding to that p0 value;

[0013] Through relation K v =p0 / s0, to obtain the spring reference stiffness coefficient K. v ;

[0014] The initial spring stiffness coefficient K of the foundation slab of the structure s0 The calculation method is as follows:

[0015] When the foundation soil is cohesive soil, (5)

[0016] When the foundation soil is sandy soil, (6)

[0017] In the formula: B is the calculated span of the base plate.

[0018] S2.2 Actual spring stiffness coefficient K of the foundation under the structural base plate si For the reaction force p of the foundation i With foundation settlement i The nonlinear value that changes with the input is calculated using the following formula:

[0019] (7)

[0020] Where a and b are the parameters of the expression for the p~s curve, respectively; when a shallow plate load test is used, , .

[0021] When using deep plate load tests , .

[0022] In the formula: I0 is the shape factor of the rigid bearing plate, which is 0.785 for a circle and 0.866 for a square; μ is the Poisson's ratio of the soil; d is the diameter or side length of the bearing plate; E0 is the initial tangent modulus of the foundation soil; p u ω represents the ultimate load of the foundation soil; ω is a coefficient related to the test depth and soil type.

[0023] S2.3, Differentiating equation (7) yields

[0024] (8)

[0025] In the formula: K si Let K be the spring stiffness coefficient of the foundation slab, and K si With pressure p i and settlement i It changes with the changes;

[0026] S3. Stiffness Iteration Calculation: Perform initial coupled calculation analysis on the calculation model, obtain the settlement and reaction force values ​​at each spring node, and update K according to equation (8). si The value is then substituted into the calculation model and recalculated, repeating the iteration until K is reached. si The value converges.

[0027] S4. Adjustment of base plate zonal variable stiffness: Based on the calculation results of the i-th iteration, obtain the contour map of the deformation of the structural base plate, and use the base plate deformation deviation value Δw as the basis for the adjustment. iBased on this, the structural base plate is divided into a large deformation deviation zone, a deformation deviation transition zone, and a small deformation deviation zone, corresponding to a stiffness strengthening zone, a stiffness transition zone, and a stiffness weakening zone, respectively. The stiffness of the structural base plate in different zones is adjusted differently to guide the redistribution of internal forces and deformations in the space. When the efficiency of stiffness changes in improving the internal forces and deformations of the structural base plate decreases, the adjustment is stopped.

[0028] S5. Foundation Stiffness Compensation: Based on the final iterative calculation results, identify the key areas for nodal spring stiffness compensation; obtain the reaction force values ​​p of the springs at each node under the structural base plate. i , with f a This represents the corrected characteristic value of the foundation bearing capacity, used to determine whether it satisfies p. i ≤f a ;

[0029] When p i >f a At that time, zonal stiffness compensation is performed to ensure that the corrected reaction force value satisfies p. i ≤f a .

[0030] Preferably, the spring stiffness coefficient K at each node of the foundation is... si All are less than the ultimate load value p of the foundation soil. u Foundation spring stiffness coefficient K si The convergence value is determined by the following formula:

[0031] (9)

[0032] In the formula: K simax To calculate the maximum value of the foundation spring stiffness coefficient in the i-th iteration; K simin To calculate the minimum value of the foundation spring stiffness coefficient in the i-th iteration; K sik For the i-th iteration, calculate the standard value of the foundation spring stiffness coefficient for each node; Δ K The stiffness coefficient convergence control standard is determined empirically.

[0033] Preferably, the settlement convergence value of the node spring is determined by the following formula:

[0034] (10)

[0035] and (11)

[0036] In the formula: s imax The maximum spring settlement at node i is calculated for the i-th iteration; s imin The minimum spring settlement of node i is calculated for the i-th iteration; Calculate the average spring settlement of each node for the i-th iteration; The average spring settlement of each node is calculated for the (i-1)th iteration; [Δs] is the settlement control standard, which can be taken as [Δs] = 0.002l. i , l i Calculate the distance between the two measurement points for the i-th iteration.

[0037] Preferably, the calculated maximum deformation w of the bottom slab structure of the water treatment tank max Determine by the following formula:

[0038] w max ≤[w max (12)

[0039] Where: specifies the maximum allowable deformation limit [w] max =0.002l0, where l0 is the calculated span of the bottom slab structure of the water treatment tank.

[0040] Preferably, the area with larger deformation deviation is the deformation deviation amplitude value Δw in the contour map of the structural base plate deformation after the i-th iteration calculation. i The 30% region represents the deformation deviation transition zone, which is the deformation deviation amplitude value Δw in the contour map of the structural base plate deformation after the i-th iteration calculation. i The region representing 15% of the total deformation is the area with the smallest deformation deviation, which is the deformation deviation amplitude Δw in the contour map of the structural base plate deformation after the i-th iteration calculation. i The region is 5%. The deformation deviation amplitude value Δw is... i Determine by the following formula:

[0041] (13)

[0042] In the formula: w im To calculate the value of the m-th contour line in the contour map of base plate deformation for the i-th iteration, w in To calculate the value of the nth contour line in the contour map of base plate deformation for the i-th iteration, w im >w in .

[0043] Preferably, in S4, based on the optimized results, the structural base plate is subjected to ultimate limit state and serviceability limit state verification calculations respectively.

[0044] Preferably, in S5, the stiffness compensation method includes at least foundation treatment and deep foundation, specifically:

[0045] When foundation treatment is adopted, after the foundation is reinforced, the reaction force correction value p of the node spring is... i ≤f spai .

[0046] When using deep foundations, the reaction force correction value of the node spring is p. i ≤R ai / Ai .

[0047] Where: f spai R is the corrected characteristic value of the bearing capacity of the composite foundation. ai The corrected characteristic value of the bearing capacity of the composite foundation; A i Calculate the reaction force p of the spring at this node for the i-th iteration. i The range of load distribution it bears.

[0048] The present invention also provides a zoned variable stiffness leveling system for the bottom plate of a water treatment tank structure, comprising:

[0049] The preprocessing module is used to establish a finite element analysis model of the water treatment tank structure, set boundary conditions, and define load conditions.

[0050] The nonlinear solver module is used to define the initial spring stiffness coefficient K. s0 The calculation process involves setting values, running iterative algorithms, partitioning the structural base plate, and determining whether the calculation results meet the convergence control criteria.

[0051] The post-processing module is used to output calculation results, perform variable stiffness leveling design of the structural base plate, and compensate key areas for spring stiffness of given nodes.

[0052] The present invention also provides a storage medium on which a computer program is stored, wherein when the computer program is executed by a processor, the steps of the above-described base plate partitioned variable stiffness leveling design method are implemented.

[0053] The present invention also provides an electronic device, including the above-mentioned storage medium for storing a computer program, and the number of storage media is at least one; it also includes at least one processor for executing the computer program to implement the steps of the above-mentioned base plate partitioned variable stiffness leveling design method.

[0054] The present invention has the following beneficial effects:

[0055] 1. Unlike laboratory tests where mechanical parameters are discrete due to sample transportation, size effects, and sample disturbance caused by unloading rebound, this invention is based on in-situ plate load tests. It fully considers the compressibility of the foundation soil and the size effect of the base plate, and constructs a nonlinear foundation spring calculation model using in-situ data, ensuring that the spring stiffness values ​​correspond one-to-one with the stress state of the foundation soil. Compared to the crude approach of simplifying the foundation soil into a "uniform linear spring" in traditional design, this technical solution can more realistically characterize the nonlinear characteristics of soil gradually hardening with increasing pressure, and can more realistically reflect the internal force and deformation state of large-area structural base plates.

[0056] 2. The value of spring stiffness directly affects the accuracy of structural analysis. This invention establishes a dynamic correlation mechanism of "settlement-reaction force-stiffness" through a stiffness iteration algorithm. By adopting the stiffness iteration calculation method, the foundation spring stiffness is no longer a fixed value, but is dynamically matched to the foundation spring stiffness coefficient continuously based on the redistribution of internal forces in the base plate and changes in foundation settlement. Through the continuous convergence of foundation settlement and the continuous leveling of the varying stiffness of the base plate, the most reasonable state of internal forces and deformation of the base plate is determined, significantly improving the accuracy of structural calculations.

[0057] 3. This invention establishes a logical chain of precise simulation, iterative optimization, zoned leveling, and targeted compensation to dynamically match the foundation stiffness with the actual stress state. Based on deformation deviation zones, it specifically enhances the stiffness of high-deformation areas and weakens the stiffness of low-deformation areas, while setting transition zones to avoid abrupt stiffness changes. This "peak-shaving and valley-filling" strategy effectively reduces differential settlement of the foundation and saves materials. Furthermore, it identifies areas with insufficient bearing capacity based on reaction force verification, allowing for foundation treatment or deep foundation design only in critical areas, avoiding the waste of large-area reinforcement.

[0058] 4. Under the premise of meeting the same deformation control standards, this scheme can save about 20% to 35% of concrete and reduce the amount of steel reinforcement by about 15% compared with the traditional uniform thickening scheme. It can avoid the additional stress generated by the soil under action due to non-uniform deformation, which may cause additional bending moment, additional shear force, or even cracking and leakage of the base plate structure. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the system framework of the base plate partitioning variable stiffness leveling design method provided by the present invention.

[0060] Figure 2 This is a schematic diagram of a structural calculation model of a water treatment tank provided in an embodiment of the present invention.

[0061] Figure 3 This is a schematic diagram of the structural base plate grid division and spring node arrangement provided in an embodiment of the present invention.

[0062] Figure 4 This is a schematic diagram of the steeply drooping p~s curve and the nonlinear spring stiffness coefficient values ​​provided in an embodiment of the present invention for an in-situ plate load test.

[0063] Figure 5 This is a schematic diagram of the slowly varying p~s curve and the nonlinear spring stiffness coefficient values ​​provided in an embodiment of the present invention for an in-situ plate load test.

[0064] Figure 6 This is a comparative illustration of the base plate arrangement of the pool structure using the conventional method (dashed lines on the base plate edge) and the present method (solid lines on the base plate edge) in one embodiment. Figure 1 .

[0065] Figure 7 This is a comparative illustration of the base plate arrangement of the pool structure using the conventional method (dashed lines on the base plate edge) and the present method (solid lines on the base plate edge) in one embodiment. Figure 2 .

[0066] In the diagram: 01, reinforcing pile; 02, base plate lattice-type hidden beam; 03, convex node anti-slip grid; 11, structural top plate; 12, structural side wall; 13, structural base plate; 131, stiffness strengthening zone; 132, stiffness transition zone; 133, stiffness weakening zone. Detailed Implementation

[0067] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0068] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0069] This invention, based on the different base reaction force distributions in the central and peripheral regions of the structural base slab 13, and combined with the nonlinear compression characteristics of the soil, proposes a zoned variable stiffness leveling design method for the water treatment tank structural base slab according to different stiffness stages of the soil. This method aims to improve the accuracy of base slab deformation and internal force calculations, ensuring the safety and stability of the water treatment tank structure's operation. Figures 6 to 7 As shown, the structural base slab 13 is divided into a stiffness-enhancing zone 131, a stiffness transition zone 132, and a stiffness-weakening zone 133. In the stiffness-enhancing zone 131, the thickness of the base slab is increased or concealed reinforcing members (such as hidden beams or ribs) are installed. This method increases the bending stiffness of the base slab structure in the stiffness-enhancing zone 131 and reduces the thickness of the base slab structure in the stiffness-weakening zone 133, thereby reducing the bending stiffness of the base slab structure. Within the same zone, the thickness adjustment of the structural base slab 13 and the reinforcement configuration can be implemented simultaneously. The stiffness transition zone 132 is located between the stiffness-enhancing zone 131 and the stiffness-weakening zone 133. The stiffness transition zone 132 continuously or progressively increases the thickness of the base slab structure, causing the bending stiffness of the base slab structure to change continuously along the structural plane, thereby reducing the adverse effects of internal force concentration caused by abrupt changes in stiffness at the boundaries of different stiffness zones.

[0070] In one embodiment provided by the present invention, such as Figure 7 As shown, the foundation environment corresponding to the bottom of the stiffness reinforcement zone 131 is soft soil, and the foundation environment corresponding to the bottom of the stiffness weakening zone 133 is hard soil (or rock foundation). Reinforcing piles 01 are installed in the soft soil at the bottom of the stiffness reinforcement zone 131, and a lattice-type hidden beam 02 is installed on the bottom wall of the structural base slab 13 at the location corresponding to the stiffness reinforcement zone 131. A continuous convex node anti-slip grid 03 is installed on the bottom wall of the structural base slab 13 at the location corresponding to the stiffness transition zone 132. The convex node anti-slip grid is made of high-strength polyester fiber material, with longitudinal and transverse tensile strengths of not less than 200 kN / m and elongation ≤10%.

[0071] like Figures 1-5 As shown, the design method includes the following steps:

[0072] S1. Establishing the computational model: Based on the process requirements and structural dimensions, establish a geometric model of the water treatment tank, and assign relevant material parameters to the geometric model. Select a suitable material model when constructing the geometric model. Divide the structural base plate 13 into a mesh model using equal-width shell elements. When dividing the equal-width shell elements, control the mesh element size and mesh the geometric model of the water treatment tank, discretizing the structural base plate 13 into a series of equal-width shell elements. Assign loads and corresponding boundary conditions to the mesh model according to the working conditions (determined by the tank load distribution, engineering geology, and hydrological conditions).

[0073] The load includes at least one of the following: side wall pressure, buoyancy, water pressure in the pool, seismic load, wind load, and static pressure of the stored liquid. The side wall pressure is calculated separately according to the geological survey report for two types of soil layers: above the groundwater level or combined water and soil, and separate water and soil. The buoyancy and water pressure in the pool are calculated by multiplying the corresponding height by the density of the medium.

[0074] The lateral pressure (i.e., the lateral pressure value of structural sidewall 12) is calculated according to the following formula based on the geological survey report:

[0075] a. For soil layers above the groundwater level or those where soil and water are considered compatible:

[0076] (1)

[0077] b. For soil layers where water and soil are calculated separately:

[0078] (2)

[0079] In the formula: p ak The standard value of active earth pressure intensity (in kPa) at the calculation point in the i-th layer of soil on the outer side of the structure, when p ak When <0, p should be taken. ak =0;σ ak Let u be the standard value of the vertical stress in the soil at the calculation point in the i-th soil layer (in kPa).a K represents the hydrostatic pressure at the calculation point (in kPa). ai c is the active earth pressure coefficient at the calculation point; i The cohesion of the i-th soil layer (in kPa).

[0080] The buoyancy (i.e., the buoyancy force on the structural base plate 13) is calculated according to the following formula based on the geological survey report:

[0081] (3)

[0082] In the formula: u w γ is the buoyancy force (in kPa) exerted by groundwater on the bottom of the structural base slab 13. w The specific gravity of groundwater is taken as 10 kN / m³. 3 h w This is the vertical distance from the groundwater level to the bottom of the structural base slab 13 (in meters).

[0083] The water pressure inside the tank (i.e., the water pressure on the top of the bottom slab when the water treatment tank is full of water) is calculated using the following formula:

[0084] (4)

[0085] In the formula: u wb The water pressure (in kPa) at the top of the bottom slab when the water treatment tank is fully filled; h wb The vertical distance (in meters) from the maximum water level to the top of the structural base plate under full-water conditions.

[0086] S2. Install nonlinear springs: At equal intervals along a direction perpendicular to the structural base plate 13, replicate the base plate element nodes. Set the replicated nodes as fixed nodes. Install nonlinear springs considering the compressibility of the foundation soil between the base plate element nodes and the replicated nodes to simulate the interaction between the foundation soil and the structural base plate; specifically:

[0087] S2.1. In-situ testing technology is adopted, and a nonlinear spring model is constructed using in-situ plate load test data to dynamically match the foundation stiffness with the actual stress state. Load-settlement correspondence values ​​are obtained from the plate load test data in the geological survey report, and a load-settlement curve is plotted, denoted as the p~s curve. The pressure p0 (in kPa) and the corresponding settlement s0 (in mm) of the linear segment of the p~s curve are selected.

[0088] When there is no straight line segment in the p~s curve, p0 is taken as the ultimate load p of the foundation soil. u (in kPa) half of the total pressure, where s0 is the settlement amount corresponding to that p0 value.

[0089] Through relation K v=p0 / s0, to obtain the spring reference stiffness coefficient K. v .

[0090] The initial spring stiffness coefficient K of the foundation slab 13 of the structure s0 (Unit: kN / m) 3 The calculation method for () is as follows:

[0091] When the foundation soil is cohesive soil, (5)

[0092] When the foundation soil is sandy soil, (6)

[0093] In the formula: B is the calculated span of the base plate (in meters).

[0094] S2.2, Actual spring stiffness coefficient K of the foundation under structural base plate 13 si For the reaction force p of the foundation i With foundation settlement i The nonlinear value that changes with the input is calculated using the following formula:

[0095] (7)

[0096] Where a and b are the parameters of the expression for the p~s curve, respectively; when a shallow plate load test is used, , .

[0097] When using deep plate load tests , .

[0098] In the formula: I0 is the shape factor of the rigid bearing plate, which is 0.785 for a circle and 0.866 for a square; μ is the Poisson's ratio of the soil; d is the diameter or side length of the bearing plate (in meters); E0 is the initial tangent modulus of the foundation soil (in kPa); p u ω represents the ultimate load of the foundation soil (in kPa); ω is a coefficient related to the test depth and soil type.

[0099] S2.3, Differentiating equation (7) yields

[0100] (8)

[0101] In the formula: K si The spring stiffness coefficient of the foundation slab (unit: kN / m) 3 ), and K si With pressure p i and settlement i It changes with the changes.

[0102] S3. Stiffness Iteration Calculation: Perform initial coupled calculation analysis on the calculation model, obtain the settlement and reaction force values ​​at each spring node, and update K according to equation (8). si The value is then substituted into the calculation model and recalculated, repeating the iteration until K is reached. si The values ​​converge until the ground spring stiffness coefficient and the nodal settlement meet the convergence control criteria. Specifically, the settlement s1 (in kPa) and reaction force p1 (in mm) at each spring node are obtained based on the finite element calculation results. The reference spring stiffness coefficient K is obtained according to equation (8). s1 , will K s1 The value is used as the updated foundation spring stiffness coefficient of the structural base plate 13 and then input into the calculation model for calculation and analysis again. Based on the finite element calculation results, the settlement s2 (in kPa) and reaction force p2 (in mm) at each spring node are obtained, and the iterative calculation steps of the above equation (8) are repeated until the foundation spring stiffness coefficient K of the structural base plate 13 is reached. si The value converges.

[0103] Through multiple rounds of stiffness iteration, the spring stiffness is dynamically adjusted with settlement and reaction force until it converges, ensuring accurate calculation results of internal force and deformation.

[0104] S4. Adjustment of variable stiffness in the base plate: Based on the calculation results of the i-th iteration, obtain the contour map of the deformation of the base plate 13, and adjust the deformation deviation value Δw of the base plate. i Based on this, the structural base plate 13 is divided into a large deformation deviation zone, a deformation deviation transition zone, and a small deformation deviation zone, corresponding to a stiffness strengthening zone 131, a stiffness transition zone 132, and a stiffness weakening zone 133, respectively. The stiffness of the structural base plate 13 in different zones is adjusted differently to guide the redistribution of internal forces and deformations in the spatial distribution of the structural base plate 13. When the efficiency of stiffness change in improving the internal forces and deformations of the structural base plate 13 decreases, the adjustment is stopped. When this scheme is running, step S4 can be performed simultaneously with step S3, or step S4 can be performed after step S3 is completed.

[0105] Based on the deformation deviation zoning, the stiffness of high deformation areas is enhanced and the stiffness of low deformation areas is weakened. At the same time, a transition zone is set to avoid abrupt changes in stiffness, which controls deformation and saves materials.

[0106] Based on the optimized results, the ultimate limit state and serviceability limit state of the structural base plate 13 were verified.

[0107] S5. Foundation Stiffness Compensation: Based on the final iterative calculation results, identify the key areas for nodal spring stiffness compensation; obtain the reaction force values ​​p of the springs at each node under the structural base plate 13. i , with f a This represents the corrected characteristic value of the foundation bearing capacity (in kPa), and it determines whether it satisfies p.i ≤f a .

[0108] When p i >f a At that time, zonal stiffness compensation is performed to ensure that the corrected reaction force value satisfies p. i ≤f a .

[0109] By identifying areas with insufficient bearing capacity through reaction force verification, foundation treatment or deep foundation design is carried out only in key areas to avoid the waste of large-area reinforcement.

[0110] Furthermore, in the above technical solution, the convergence value of the node spring settlement is determined by the following formula:

[0111] (10)

[0112] and (11)

[0113] In the formula: s imax The maximum spring settlement of the node is calculated in mm during the i-th iteration; s imin The minimum spring settlement of node i is calculated in mm during the i-th iteration. Calculate the average spring settlement of each node (in mm) for the i-th iteration; The average spring settlement of each node is calculated (in mm) for the (i-1)th iteration; [Δs] is the settlement control standard, which can be taken as [Δs] = 0.002l. i , l i Calculate the distance between the two measurement points for the i-th iteration.

[0114] Furthermore, in the above technical solution, the calculated maximum deformation w of the water treatment tank bottom slab structure... max Determine by the following formula:

[0115] w max ≤[w max (12)

[0116] Where: specifies the maximum allowable deformation limit [w] max =0.002l0, where l0 is the calculated span of the bottom slab structure of the water treatment tank.

[0117] Furthermore, in the above technical solution, the area with larger deformation deviation is the deformation deviation amplitude value Δw in the contour map of the deformation of the structural base plate 13 after the i-th iteration calculation. i The 30% area represents the deformation deviation transition zone, which is the deformation deviation amplitude value Δw in the contour map of the deformation of the structural base plate 13 after the i-th iteration calculation. iThe region with a 15% deformation deviation is represented by the deformation deviation amplitude Δw in the contour map of the deformation of the structural base plate 13 after the i-th iteration calculation. i The region is 5%. The deformation deviation amplitude value Δw is... i Determine by the following formula:

[0118] (13)

[0119] In the formula: w im To calculate the value of the m-th contour line in the contour map of base plate deformation for the i-th iteration, w in To calculate the value of the nth contour line in the contour map of base plate deformation for the i-th iteration, w im >w in .

[0120] This invention also provides a zonal variable stiffness leveling system for the bottom plate of a water treatment tank structure, including a preprocessing module, a nonlinear solution module, and a post-processing module. The preprocessing module is used to establish a finite element analysis model of the water treatment tank structure, set boundary conditions, and define load cases. The nonlinear solution module is used to define the initial spring stiffness coefficient K. s0 The system calculates the value, runs the iterative algorithm, partitions the structural base plate, and determines whether the calculation results meet the convergence control criteria. The post-processing module is used to output the calculation results, perform leveling design of the 13 variable stiffness sections of the structural base plate, and compensate key areas for spring stiffness at given nodes.

[0121] The present invention also provides a storage medium on which a computer program is stored, wherein when the computer program is executed by a processor, the steps of the above-described base plate partitioned variable stiffness leveling design method are implemented.

[0122] The present invention also provides an electronic device, including the above-mentioned storage medium for storing a computer program, and the number of storage media is at least one; it also includes at least one processor for executing the computer program to implement the steps of the above-mentioned base plate partitioned variable stiffness leveling design method.

[0123] To facilitate the implementation and operation of this invention by those skilled in the art, a specific example is given below.

[0124] This embodiment provides a large-scale advanced treatment tank for industrial wastewater, used for the advanced treatment of industrial wastewater. The treatment tank is a reinforced concrete structure with a base slab plan dimension of 72.5 × 22.5 m, a total structural height of 9.5 m, and the top of the tank exceeding the designed ground level. The bottom of the base slab is buried at a depth of -4.5 m (relative to ±0.000 m), and the groundwater level is -0.5 m (relative to ±0.000 m). The vertical distance h from the maximum water level line to the top of the structural base slab under full-water conditions is [not specified]. wbThe depth is 8m. The investigation revealed uneven distribution of the foundation soil: approximately three-fifths of the eastern area consists of a deep soft soil layer. The corrected characteristic value of the foundation bearing capacity f... a =90kPa, reference stiffness coefficient K v 8000kN / m 3 Its bearing capacity is low and its compressibility is high; about two-fifths of the western area is directly composed of moderately weathered rock bed, and the characteristic value of the foundation bearing capacity f is low. a =1500kPa, reference stiffness coefficient K v 750000 kN / m 3 It has high bearing capacity and small deformation. To coordinate the huge differential settlement between soft soil and rock foundation and to ensure the overall stress safety of the base plate, the base plate zonal variable stiffness leveling design method of this invention is adopted. After accurate simulation, iterative optimization, zonal leveling, and targeted compensation, the design scheme is as follows: Figure 7 As shown in Table 1, the result parameters of the method of the present invention and the conventional method are as follows:

[0125] Table 1. Comparison of parameters between the embodiments provided by the present invention and traditional design schemes

[0126]

[0127] Under the premise of meeting the same deformation control standards, compared with the traditional uniform thickening of the base plate, the amount of concrete used in the base plate of the present invention is about 67.6% of that of the traditional design method, saving 32.4%, which has a significant economic effect.

[0128] The above are preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A zonal variable stiffness leveling design method for the base plate, which divides the structural base plate into a stiffness-enhancing zone, a stiffness transition zone, and a stiffness-weakening zone. In the stiffness-enhancing zone, the thickness of the base plate is increased or concealed reinforcing components are installed; in the stiffness-weakening zone, the thickness of the base plate is reduced; and the stiffness transition zone is located between the stiffness-enhancing zone and the stiffness-weakening zone. Its characteristics are: Includes the following steps: S1. Establish the calculation model: Construct a geometric model of the water treatment tank and assign it relevant material parameters; divide the structural base plate into equal-width shell element meshes to form a mesh model; assign loads and corresponding boundary conditions to the mesh model according to the working conditions. S2. Install nonlinear springs: Copy the base plate element nodes at equal intervals along the direction perpendicular to the base plate, set the copied nodes as fixed nodes, and install nonlinear springs that take into account the compressibility of the foundation soil between the base plate element nodes and the copied nodes to simulate the interaction between the foundation soil and the base plate. Specifically: S2.1 Obtain the load-settlement correspondence value from the plate load test data in the geological survey report, plot the load-settlement curve, denoted as the p~s curve, and select the pressure p0 and the settlement s0 corresponding to p0 in the linear segment of the p~s curve. When there is no straight line segment in the p~s curve, p0 is taken as the ultimate load p of the foundation soil. u Half of the value of p0, where s0 is the settlement amount corresponding to the value of p0; Through relation K v =p0 / s0, to obtain the spring reference stiffness coefficient K. v ; The initial spring stiffness coefficient K of the foundation slab of the structure s0 The calculation method is as follows: When the foundation soil is cohesive soil, (5) When the foundation soil is sandy soil, (6) In the formula: B is the calculated span of the base plate; S2.2 Actual spring stiffness coefficient K of the foundation under the structural base plate si For the reaction force p of the foundation i With foundation settlement i The nonlinear value that changes with the input is calculated using the following formula: （7） Where a and b are the parameters of the expression for the p~s curve, respectively; S2.3, Differentiating equation (7) yields （8） Where: K si Let K be the spring stiffness coefficient of the foundation slab, and K si With pressure p i and settlement i The value changes with the change; d is the diameter or side length of the pressure plate. S3. Stiffness Iteration Calculation: Perform initial coupled calculation analysis on the calculation model, obtain the settlement and reaction force values ​​at each spring node, and update K according to equation (8). si The value is then substituted into the calculation model and recalculated, repeating the iteration until K is reached. si The value converges until the convergence occurs; S4. Adjustment of base plate zonal variable stiffness: Based on the calculation results of the i-th iteration, obtain the contour map of the deformation of the structural base plate, and use the base plate deformation deviation value Δw as the basis for the adjustment. i Based on this, the structural base plate is divided into a large deformation deviation zone, a deformation deviation transition zone, and a small deformation deviation zone, which correspond to the stiffness strengthening zone, stiffness transition zone, and stiffness weakening zone, respectively. The stiffness of the structural base plate in different zones is adjusted differently to guide the redistribution of internal forces and deformations in the structural base plate in space until the efficiency of stiffness changes in improving the internal forces and deformations of the structural base plate decreases. S5. Foundation Stiffness Compensation: Based on the final iterative calculation results, identify the key areas for nodal spring stiffness compensation; obtain the reaction force values ​​p of the springs at each node under the structural base plate. i , with f a This represents the corrected characteristic value of the foundation bearing capacity, used to determine whether it satisfies p. i ≤f a ; When p i >f a At that time, perform zoned stiffness compensation until p is satisfied. i ≤f a .

2. The base plate partitioned variable stiffness leveling design method according to claim 1, characterized in that: In S2.2, when a shallow plate load test is used, , ; When using deep plate load tests , ; In the formula: I0 is the shape factor of the rigid bearing plate, which is 0.785 for a circle and 0.866 for a square; μ is the Poisson's ratio of the soil; d is the diameter or side length of the bearing plate; E0 is the initial tangent modulus of the foundation soil; ω is a coefficient related to the test depth and soil type.

3. The base plate partitioned variable stiffness leveling design method according to claim 1, characterized in that: Spring stiffness coefficient K at each node of the foundation si All are less than the ultimate load value p of the foundation soil. u Foundation spring stiffness coefficient K si The convergence value is determined by the following formula: （9） Where: K simax To calculate the maximum value of the foundation spring stiffness coefficient in the i-th iteration; K simin To calculate the minimum value of the foundation spring stiffness coefficient in the i-th iteration; K sik For the i-th iteration, calculate the standard value of the foundation spring stiffness coefficient for each node; Δ K The stiffness coefficient convergence control standard is determined empirically.

4. The base plate partitioned variable stiffness leveling design method according to claim 1, characterized in that: The convergence value of the node spring settlement is determined by the following formula: （10） and (11) In the formula: s imax The maximum spring settlement at node i is calculated for the i-th iteration; s imin The minimum spring settlement of node i is calculated for the i-th iteration; Calculate the average spring settlement of each node for the i-th iteration; The average spring settlement of each node is calculated for the (i-1)th iteration; [Δs] is the settlement control standard, which can be taken as [Δs] = 0.002l. i , l i Calculate the distance between the two measurement points for the i-th iteration.

5. The base plate partitioned variable stiffness leveling design method according to claim 1, characterized in that: The maximum deformation w of the bottom slab structure of the water treatment tank was calculated. max Determine using the following formula: In max ≤[in max ] (12) Where: specifies the maximum allowable deformation limit [w] max =0.002l0, where l0 is the calculated span of the bottom slab structure of the water treatment tank.

6. The base plate partitioned variable stiffness leveling design method according to claim 1, characterized in that: The area with larger deformation deviation is the area represented by the deformation deviation amplitude Δw in the contour map of the structural base plate deformation after the i-th iteration calculation. i The 30% region represents the deformation deviation transition zone, which is the deformation deviation amplitude value Δw in the contour map of the structural base plate deformation after the i-th iteration calculation. i The region representing 15% of the total deformation is the area with the smallest deformation deviation, which is the deformation deviation amplitude Δw in the contour map of the structural base plate deformation after the i-th iteration calculation. i The area is 5%, where the deformation deviation amplitude value Δw i Determine using the following formula: （13） In the formula: w im To calculate the value of the m-th contour line in the contour map of base plate deformation for the i-th iteration, w in To calculate the value of the nth contour line in the contour map of base plate deformation for the i-th iteration, w im >w in .

7. The base plate partitioned variable stiffness leveling design method according to claim 1, characterized in that: In S5, stiffness compensation methods include at least foundation treatment and deep foundations, specifically: When foundation treatment is adopted, after the foundation is reinforced, the reaction force correction value p of the node spring is... i ≤f spai ; When using deep foundations, the reaction force correction value of the node spring is p. i ≤R ai / A i ; Where: f spai R is the corrected characteristic value of the bearing capacity of the composite foundation. ai The corrected characteristic value of the bearing capacity of the composite foundation; A i Calculate the reaction force p of the spring at this node for the i-th iteration. i The range of load distribution it bears.

8. A zonal variable stiffness leveling system for the bottom plate of a water treatment tank structure, applied to the zonal variable stiffness leveling design method of any one of claims 1-7, characterized in that: include: The preprocessing module is used to establish a finite element analysis model of the water treatment tank structure, set boundary conditions, and define load cases. The nonlinear solver module is used to define the initial spring stiffness coefficient K. s0 The calculation process involves setting values, running iterative algorithms, partitioning the structural base plate, and determining whether the calculation results meet the convergence control criteria. The post-processing module is used to output calculation results, perform variable stiffness leveling design of the structural base plate, and compensate key areas for spring stiffness of given nodes.

9. A storage medium, characterized in that: A computer program is stored on a storage medium, which, when executed by a processor, implements the steps of the base plate partitioning variable stiffness leveling design method as described in any one of claims 1-7.

10. An electronic device, characterized in that: Includes the storage medium as described in claim 9, for storing a computer program, and the number of storage media is at least one; It also includes at least one processor for executing the computer program to implement the steps of the base plate partition variable stiffness leveling design method according to any one of claims 1-7.

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