Load calculation method for dam simulation test chamber based on constant load and live load analysis

Abstract

The present application relates to a dam simulation test cabin load calculation method based on constant load and live load analysis, comprising: determining the weight distribution of the test cabin; obtaining the structural parameters of the test cabin; building a finite element model of the test cabin; analyzing and calculating the constant load and live load of the test cabin, and performing load combination analysis; according to the load combination analysis result, the maximum displacement of the dam simulation test cabin under different combined loads is calculated; the stress field and strain distribution of the dam simulation test cabin are calculated by using the finite element model; the structure and parameters of the test cabin are adjusted to determine whether the dam simulation test cabin meets the safety design requirements. The present application analyzes the load effect of the dam simulation test cabin under various load combination conditions, analyzes the stress field and strain distribution of the test cabin under combined loads, calculates the maximum deformation displacement of the test cabin under different combined loads, and provides a scientific basis for the safety design of the dam simulation test cabin.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of hydropower engineering monitoring, and particularly relates to a load analysis method for a dam simulation test cabin. BACKGROUND

[0002] The environment of a water conservancy project site is extremely complex, especially in the northwest region, where severe cold, great temperature difference, strong wind, rainstorm and snowstorm and other adverse and changeable weather conditions exist. Meanwhile, adverse weather conditions can also cause disasters such as floods and mudslides. In the western canyon area, dam construction of a hydropower project faces many technical difficulties. Before dam construction, scientific tests need to be carried out in advance to solve the technical difficulties. During the dam construction process, simulation needs to be carried out to prepare for adverse situations as soon as possible.

[0003] In order to effectively carry out scientific tests in such an environment, a dam simulation test cabin with comprehensive functions and capable of carrying various instruments and equipment needs to be constructed. Moreover, the test cabin must have sufficient structural strength to resist the single or combined effects of various external loads such as wind, snow and earthquakes.

[0004] Therefore, a comprehensive load analysis of the dam simulation test cabin needs to be carried out at the initial design stage. Through the analysis results, necessary adjustments and optimization of the structure are carried out to ensure that the dam simulation test cabin can not only bear the dead load, i.e. its own weight, but also effectively resist the adverse effects of live loads such as wind, snow and load combination. SUMMARY

[0005] The purpose of the present application is to provide a dam simulation test cabin load calculation method based on dead load and live load analysis to analyze and calculate the dead load of the dam simulation test cabin and the live load of the dam simulation test cabin under adverse, extreme and complex weather conditions, analyze the load effect of the dam simulation test cabin under various load combinations, judge the safety and stability of the structure design of the dam simulation test cabin, construct a finite element model of the dam simulation test cabin, analyze the stress field and strain distribution of the dam simulation test cabin under combined load, calculate the most unfavorable displacement deformation of the dam simulation test cabin, and provide a scientific basis for the safety design of the dam simulation test cabin to ensure the structural safety of the dam simulation test cabin under extreme weather conditions.

[0006] The technical solution of the present application is a dam simulation test cabin load calculation method based on dead load and live load analysis, which comprises the following steps:

[0007] Step 1: determining the overall weight of the dam simulation test cabin, the weight distribution of the cabin body and the design requirements for the safety of the test cabin; obtaining the overall structure, cross-sectional information, structural parameters and material selection of the test cabin;

[0008] Step 2: Establish a finite element model of the dam simulation test chamber, i.e., a structural analysis model, set the materials of the dam simulation test chamber in the finite element model, and set the parameters of the finite element model according to the data obtained in step 1;

[0009] Step 2.1: Use finite element software to construct a finite element model of the dam simulation test chamber, and select the materials of the dam simulation test chamber in the finite element model according to the design structure and material selection of the dam simulation test chamber, including the steel type and specification of different parts of the dam simulation test chamber framework structure;

[0010] Step 2.2: Set the cross section of the dam simulation test chamber framework structure member in the finite element model, including the cross section of the main beam, the cross section of the pull rod, and the cross section of the support rod;

[0011] Step 2.3: Determine the element type of the finite element model of the dam simulation test chamber;

[0012] Step 2.4: Divide the elements of the finite element model of the dam simulation test chamber, and determine the nodes and elements of the finite element model of the dam simulation test chamber in combination with the design structure and size of the dam simulation test chamber;

[0013] Step 2.5: Set the element properties in the finite element model of the dam simulation test chamber, and add the materials and cross section parameters to the elements of the finite element model according to the overall structure, cross section information, structural parameters, and material selection data of the dam test chamber obtained in step 1.

[0014] Step 3: Calculate the elastic modulus, Poisson's ratio, and linear expansion coefficient of the dam simulation test chamber structure;

[0015] Step 3.1: Calculate the elastic modulus of the material of the dam simulation test chamber structure member;

[0016] Step 3.2: Calculate the Poisson's ratio of the material of the dam simulation test chamber structure member;

[0017] Step 3.3: Calculate the linear expansion coefficient of the material of the dam simulation test chamber structure member;

[0018] Step 4: Analyze and calculate the dead load and live load of the dam simulation test chamber, and perform load combination analysis;

[0019] Step 5: According to the load combination analysis results obtained in step 4, calculate the maximum displacement of the dam simulation test chamber under different combined loads;

[0020] Step 6: Use the finite element model of the dam simulation test chamber to perform calculation and obtain the stress field and strain distribution of the dam simulation test chamber;

[0021] Step 7: According to the calculation results of step 5 and step 6, judge whether the dam simulation test chamber meets the design requirements of structural safety? If it meets the requirements, end; if it does not meet the requirements, adjust the structure and parameters of the test chamber, and execute steps 1-6 again.

[0022] Preferably, step 4 includes the following sub-steps:

[0023] Step 4.1: Analyze and calculate the dead load of the dam simulation test chamber;

[0024] Step 4.2: Analyze and calculate the live load of the dam simulation test chamber;

[0025] Step 4.2.1: Calculate the dynamic load of the personnel in the dam simulation test chamber;

[0026] Step 4.2.2: Calculate the wind load borne by the dam simulation test chamber;

[0027] Step 4.2.3: Analyze and calculate the snow load of the dam simulation test chamber;

[0028] Step 4.2.4: Analyze and calculate the sediment flow load of the dam simulation test chamber;

[0029] Step 4.2.5: Analyze and calculate the temperature load of the dam simulation test chamber;

[0030] Step 4.2.6: Analyze and calculate the seismic load of the dam simulation test chamber;

[0031] Step 4.3: Calculate the load effect of the dam simulation test chamber under the combined load.

[0032] Preferably, step 5 includes the following sub-steps:

[0033] Step 5.1: Using the finite element model of the dam simulation test chamber, according to the dead load and live load of the dam simulation test chamber obtained in step 4, calculate the resisting deformation force and torque of the dam simulation test chamber under different combined loads, including axial force, shear force, bending moment and torque;

[0034] Step 5.2: Calculate the maximum deformation displacement of the dam simulation test chamber under different combined loads, including the maximum deformation displacement in X, Y and Z axis directions.

[0035] Preferably, in step 3.1, the formula for calculating the elastic modulus is:

[0036] E = σ / ε

[0037] In the formula, E represents the elastic modulus of the material of the component,σ , ε respectively represent the stress and strain of the component material;

[0038] Preferably, in step 3.2, the calculation formula of the Poisson's ratio is:

[0039] V = ε 1 / ε 2

[0040] wherein V represents the Poisson's ratio of the component material; ε 1 is the lateral strain, i.e. the deformation amount perpendicular to the load direction, ε 2 is the axial strain, i.e. the deformation amount along the load direction;

[0041] In step 3.3, the calculation formula of the linear expansion coefficient is:

[0042] CTE = (Δ L / L 0) * Δ T

[0043] wherein CTE represents the linear expansion coefficient of the component material, Δ L represents the change amount of the length of the component material when the temperature changes, L 0 represents the initial length of the component material; and Δ T represents the temperature change amount.

[0044] Further, in step 4.1, the constant load is the dead weight of the dam simulation test chamber, including the weight of the skeleton structure, the surface layer of the dam simulation test chamber and the fixed equipment in the dam simulation test chamber.

[0045] Preferably, in step 4.2.1, the calculation formula of the dynamic load of the personnel is:

[0046] Q = k × γ × L

[0047] wherein Q represents the dynamic load of the personnel, k is the coefficient of the dynamic load, γ is the unit weight of the dynamic load, L is the action length of the dynamic load.

[0048] Preferably, in step 4.2.2, the calculation formula of the wind load is:

[0049]

[0050] wherein represents the unit wind load perpendicular to the surface of the dam simulation test chamber, is the wind vibration coefficient, z represents the height, is the wind load shape coefficient, is the basic wind pressure value, represents the wind pressure height variation coefficient.

[0051] Preferably, in step 4.2.3, the calculation formula of the snow load is:

[0052]

[0053] wherein is the snow load value; is the top snow distribution coefficient; is the basic snow pressure, i.e. the self-weight of snow per unit area.

[0054]

[0055] wherein h is the snow depth; p is the snow density; g is the acceleration of gravity.

[0056] Preferably, in step 4.2.4, the calculation formula of the sediment flow load is:

[0057]

[0058] wherein is the impact pressure of the sediment flow on the dam simulation test chamber, is the flow velocity of the sediment flow, g is the acceleration of gravity, α is the angle between the impact direction of the sediment flow on the dam simulation test chamber and the horizontal direction, λ is the shape coefficient of the dam simulation test chamber.

[0059] Preferably, in step 4.2.5, the calculation formula of the temperature load is:

[0060] T l CTE T E

[0061] wherein T l is the temperature load of the dam simulation test chamber, CTE is the linear expansion coefficient, Δ T is the temperature change amount, E is the overall structural elastic modulus of the test chamber. ​​​

[0062] Further, in step 4.2.6, the calculation formula of the seismic load is:

[0063]

[0064] wherein V represents the seismic load of the dam simulation test chamber, is the ratio of the design spectrum acceleration of the site level to the gravity acceleration; g is the use coefficient; I is the initial yield seismic force amplification factor, is the seismic force reduction factor of the dam simulation test chamber, is the static load of the dam simulation test chamber; W wherein

[0065] is related to the allowable lateral displacement capacity and the natural vibration period of the dam simulation test chamber, the calculation formula is: T

[0066]

[0067] wherein represents the short-period and medium-period dividing corner period value, represents the allowable lateral displacement capacity of the dam simulation test chamber; T represents the natural vibration period of the dam simulation test chamber.

[0068] Preferably, in step 4.3, the following limit state equation is used to analyze and calculate the load effect of the dam simulation test chamber under the combined load:

[0069]

[0070] wherein g represents the structure function function; = 1, 2, …, N is the input variable of the structure function function, including various load actions of the dam simulation test chamber and the material properties and geometric parameters of the components, N is the number of input variables;

[0071] When the input variables of the structure function function of the dam simulation test chamber are equivalent to the action effect and the structure resistance, the stability condition of the dam simulation test chamber is

[0072]

[0073] wherein S represents the action effect of the structure; R represents the resistance of the structure. ​​

[0074] When analyzing the combined load of the dam simulation test chamber, Turkstra combined rule is adopted. Firstly, it is assumed that only one load effect reaches the maximum value among all load effects of the dam simulation test chamber, and other load effects are time point values, and the combination is carried out in turn, wherein the combination with control effect is the combination with minimum structural reliability in structural reliability analysis. There are n load participating in the combined analysis, and the i load corresponding time point probability distribution function is , the probability density function of the load is , t represents the time;

[0075] According to the Turkstra combined rule, n there are combination situations:

[0076]

[0077]

[0078]

[0079] In the formula, represents the arbitrary time point, T D is the design reference period, , , …. respectively represent the total load of the dam simulation test chamber under the first, second, …, and n combination situations of the load.

[0080] The calculation formula of the stability of the dam simulation test chamber under the combined load situation of the structural member considering the bearing capacity limit state is:

[0081]

[0082] In the formula , represents the structural importance coefficient; represents the partial coefficient of constant load; represents the load effect of constant load; represents the partial coefficient of the i live load, represents the combination coefficient of the i live load; represents the load effect of the i live load with control effect; R ( ) represents the resistance generated by the dam simulation test chamber under the combined load effect; Resistance coefficient of structural member of dam simulation test cabin; Material performance parameter of dam simulation test cabin, Geometric parameter of structural member of dam simulation test cabin.

[0083] Compared with the prior art, the beneficial effects of the present application include:

[0084] 1) The present application analyzes and calculates the dead load and various live loads of the dam simulation test cabin, analyzes the load effect of the dam simulation test cabin under various load combinations, judges the stability of the dam simulation test cabin, and analyzes the stress field and strain distribution of the dam simulation test cabin under combined loads by using finite element software, calculates the maximum displacement of the dam simulation test cabin under different combined loads, provides a scientific basis for the safety design of the dam simulation test cabin, ensures the structural safety and stability of the dam simulation test cabin under extreme meteorological conditions, can adapt to the severe weather conditions of the hydropower engineering site in the west, and ensures the smooth development of scientific tests in the construction of hydropower engineering.

[0085] 2) The present application calculates the seismic load of the dam simulation test cabin, and analyzes and calculates the stability of the dam simulation test cabin under the combination of seismic load and other loads, which can improve the anti-seismic performance of the dam simulation test cabin.

[0086] 3) The present application calculates the snow load of the dam simulation test cabin, and analyzes and calculates the stability of the dam simulation test cabin under the combination of snow load and other loads, which improves the structural safety of the high dam simulation test cabin under heavy snow cover and accumulation, and makes the dam simulation test cabin adapt to the weather environment of frequent snowfall and perennial snow in the western high-altitude area, providing protection for the smooth progress of scientific tests of hydropower engineering.

[0087] 4) The present application analyzes and calculates the temperature load caused by large temperature difference at the hydropower engineering construction site, which is convenient for the large temperature difference between day and night at the hydropower engineering site in the west, enhances the structural strength design of the dam simulation test cabin, and further ensures the safety and stability of the dam simulation test cabin under extreme meteorological conditions.

[0088] 5) The present application analyzes and calculates the wind load under strong wind conditions at the hydropower engineering construction site and the influence of the wind load on the dam simulation test cabin, enhances the ability of the dam simulation test cabin to withstand strong wind, and makes the dam simulation test cabin adapt to the strong wind and sand environment of the hydropower engineering site in the west.

[0089] 6) The present application analyzes and calculates the impact force of sediment flow on the dam simulation test cabin, analyzes its destructive effect on the dam simulation test cabin, further improves the structural reliability of the dam simulation test cabin, and enhances the ability of the dam simulation test cabin to resist the impact of flood and debris flow at the hydropower engineering site. BRIEF DESCRIPTION OF DRAWINGS

[0090] The application will be further described below in connection with the accompanying drawings and examples.

[0091] Figure 1 The flowchart of the dam simulation test cabin load calculation method of the embodiment of the application.

[0092] Figure 2 The design model of the dam simulation test cabin of the embodiment of the application.

[0093] Figure 3 The skeleton structure diagram of the dam simulation test cabin of the embodiment of the application.

[0094] Figure 4 The constant load distribution diagram of the dam simulation test cabin of the embodiment of the application.

[0095] Figure 5 The wind load distribution diagram of the dam simulation test cabin of the embodiment of the application.

[0096] Figure 6 The snow load distribution diagram of the dam simulation test cabin of the embodiment of the application.

[0097] Figure 7 The schematic diagram of the maximum displacement node under the combined load of the embodiment of the application. DETAILED DESCRIPTION

[0098] A large-scale water conservancy hub project is located in the northern part of Xinjiang Uygur Autonomous Region of China, and the water retaining structure thereof adopts a double-curvature arch dam with a maximum dam height of 240 m and a dam top length of 791 m; the dam is the first special high arch dam built in a high-latitude cold region in China. The dam site is located in a cold region, and the winter is cold and long, with the longest freezing time being 154 days; the annual average temperature is 2.8℃, the annual maximum extreme temperature is 36.6℃, the annual minimum temperature is -45℃, the annual maximum extreme temperature difference is 81.6℃, the maximum snow depth is 76 cm, the maximum thickness of frozen soil is 220 cm, and the maximum wind speed is 35.1 m / s; the concrete construction winter shutdown period is from November to the next April every year, and the annual construction time is 6 months, of which the effective pouring time of dam concrete is 5 months.

[0099] Since the project is located in a high-latitude, strong earthquake, and high-cold region, it faces complex working conditions such as short construction period, large temperature difference, and long intermittent period. Compared with other similar projects, the climate condition is more complex and severe, the comprehensive anti-cracking ability of concrete is relatively poor, the dam concrete temperature control and crack prevention requirement is high, the temperature control technical scheme needs to be researched comprehensively and refined, more strict temperature control and crack prevention measures are taken in dam construction process, temperature control and crack prevention, and the cracking risk of dam concrete and crack treatment cost are reduced.

[0100] Before the main body engineering construction, scientific test and dam construction, construction simulation are carried out by using dam simulation test cabin to carry out research work on the temperature control technical problems of the hydropower project. When designing the dam simulation test cabin, load calculation and analysis are carried out on the dam simulation test cabin to improve the safety and stability of the structure under complex and extreme weather conditions, so as to adapt to the severe weather conditions of the hydropower project site in the west and ensure the smooth development of scientific tests in the construction of the hydropower project.

[0101] In the embodiment, the design model of the dam simulation test cabin is as shown in Figure 2 The skeleton structure of the dam simulation test cabin is as shown in Figure 3 Figure 3 In the embodiment, the 1# structural member adopts rectangular hollow steel, and the cross-sectional shape is a rectangle of 250mm×150mm; the 2# structural member adopts rectangular hollow steel, and the cross-sectional shape is a rectangle of 200mm×120mm; the 3# structural member adopts rectangular hollow steel, and the cross-sectional shape is a rectangle of 80mm×40mm; and the 4# structural member adopts rectangular hollow steel, and the cross-sectional shape is a square of 80mm×80mm, as shown in Table 1.

[0102] Table 1 Skeleton structure parameter table of dam simulation test cabin

[0103]

[0104] As shown in Figure 1 The load calculation method of the dam simulation test cabin based on constant load and live load analysis includes the following steps:

[0105] Step 1: determining the overall weight of the dam simulation test cabin, the weight distribution of the cabin body, and the design requirements for the safety of the test cabin; obtaining the overall structure, cross-sectional information, structural parameters and material selection of the test cabin;

[0106] Step 1.1: according to the functional requirements of the dam test cabin, determining the material and structural parameters of the test cabin, including the overall shape and size of the dam simulation test cabin and the control range and requirements of the test cabin weight;

[0107] Step 1.2: using 3D3S software to model the dam simulation test cabin to obtain the test cabin model;

[0108] Step 1.3: according to the test cabin model of step 1.2, obtaining the overall structure, cross-sectional information and structural parameters of the dam simulation test cabin.

[0109] Step 2: establishing a finite element model of the dam simulation test cabin, i.e. a structure analysis model, setting the material of the dam simulation test cabin in the finite element model, and setting the parameters of the finite element model according to the data obtained in step 1; ​

[0110] Step 2.1: A finite element analysis model of the dam simulation test cabin is constructed by using Midas finite element software, and the materials of the dam simulation test cabin are selected in the finite element model according to the design structure and material selection of the dam simulation test cabin, including the steel type and specification of different parts of the dam simulation test cabin framework structure;

[0111] Step 2.2: The cross sections of the framework structure members of the dam simulation test cabin are set in the finite element model, including the cross sections of the main beam, the pull rod and the support rod;

[0112] Step 2.3: The unit type of the finite element model of the dam simulation test cabin is determined;

[0113] Step 2.4: The units of the finite element model of the dam simulation test cabin are divided, and the nodes and units of the finite element model of the dam simulation test cabin are determined in combination with the design structure and size of the dam simulation test cabin;

[0114] Step 2.5: The unit properties in the finite element model of the dam simulation test cabin are set, and the materials and cross section parameters are added to the units of the finite element model according to the overall structure, cross section information, structure parameters and material selection data of the dam test cabin obtained in step 1.

[0115] Step 3: Calculate the elastic modulus, Poisson's ratio and linear expansion coefficient of the dam simulation test cabin structure;

[0116] Step 3.1: Calculate the elastic modulus of the material of the dam simulation test cabin structure member;

[0117] The calculation formula of the elastic modulus is:

[0118] E = σ / ε

[0119] In the formula, E represents the elastic modulus of the material of the member, σ , ε respectively represent the stress and strain of the material of the member;

[0120] Step 3.2: Calculate the Poisson's ratio of the material of the dam simulation test cabin structure member;

[0121] The calculation formula of the Poisson's ratio is:

[0122] V = ε 1 / ε 2

[0123] In the formula, V represents the Poisson's ratio of the material of the member; ε 1 is the transverse strain, i.e. the deformation perpendicular to the load direction,ε 2 is axial strain, i.e. deformation along the load direction;

[0124] Step 3.3: Calculate the linear expansion coefficient of the material of the structural member of the dam simulation test chamber;

[0125] The calculation formula of the linear expansion coefficient is:

[0126] CTE = (Δ L / L 0) * Δ T

[0127] In the formula, CTE represents the linear expansion coefficient of the material of the member, L represents the change in the length of the material of the member when the temperature changes, L 0 represents the initial length of the material of the member; and T represents the temperature change.

[0128] Step 4: Analyze and calculate the dead load and live load of the dam simulation test chamber, and perform load combination analysis;

[0129] Step 4.1: Analyze and calculate the dead load of the dam simulation test chamber, which is the dead load of the dam simulation test chamber, including the weight of the skeleton structure, the surface layer of the dam simulation test chamber, and the fixed equipment in the dam simulation test chamber.

[0130] The load value distribution of the dead load of the dam simulation test chamber in the embodiment is shown in Figure 4 , wherein the red part represents a load value of 2500 kN / m2, and the orange part represents a surface load value of 0.3 kN / m 2 .

[0131] Step 4.2: Analyze and calculate the live load of the dam simulation test chamber;

[0132] Step 4.2.1: Calculate the dynamic load of the personnel in the dam simulation test chamber;

[0133] The calculation formula of the dynamic load of the personnel is:

[0134] Q = k × γ × L

[0135] In the formula, Q represents the dynamic load of the personnel, k is the coefficient of the dynamic load, γ is the unit weight of the dynamic load, L is the action length of the dynamic load.

[0136] Step 4.2.2: Calculate the wind load on the dam simulation test chamber;

[0137] The formula for calculating the wind load is:

[0138]

[0139] wherein represents the unit wind load perpendicular to the surface of the dam simulation test chamber, is the wind vibration coefficient, z represents the height, is the wind load shape coefficient, is the basic wind pressure value, represents the wind pressure height variation coefficient.

[0140] In the embodiment, the damping ratio for calculating the wind load is 0.02, the wind load shape coefficient is 0.8, and the basic wind pressure value is 0.55 N / m 2 . The load value distribution of the wind load on the dam simulation test chamber calculated is shown in Figure 5 , wherein the red part represents a load value of -0.5 KN / m2, and the orange part represents a load value of 0.8 KN / m 2 .

[0141] Step 4.2.3: Analyze and calculate the snow load on the dam simulation test chamber;

[0142] The formula for calculating the snow load is:

[0143]

[0144] wherein is the snow load value; is the top snow distribution coefficient; is the basic snow pressure, i.e., the self-weight of snow per unit area;

[0145]

[0146] wherein h is the snow depth; p is the snow density; g is the acceleration of gravity.

[0147] In the embodiment, the load value distribution of the snow load on the dam simulation test chamber in a heavy snow weather is shown in Figure 6 , wherein the red part represents a load value of 0.5 kN / m 2 .

[0148] Step 4.2.4: Analyze and calculate the sediment flow load on the dam simulation test chamber;

[0149]

[0150] In the formula F The impact pressure of sediment flow on the dam simulation test chamber. The velocity of the sediment flow. g It is the acceleration due to gravity. α The angle between the impact direction of the sediment flow on the dam simulation test chamber and the impact surface of the dam simulation test chamber. λ The shape factor of the dam simulation test chamber.

[0151] Step 4.2.5: Analyze and calculate the temperature load of the dam simulation test chamber;

[0152] The formula for calculating temperature load is:

[0153] T l = CTE *Δ T * E

[0154] in T l For the temperature load of the dam simulation test chamber, CTE Δ is the coefficient of linear expansion. T The change in temperature E The elastic modulus of the overall structure of the test chamber.

[0155] Step 4.2.6: Analyze and calculate the seismic load on the dam simulation test chamber;

[0156] The formula for calculating seismic load is:

[0157]

[0158] In the formula V This indicates the seismic load of the dam simulation test chamber. Design spectral acceleration and gravitational acceleration at the site g The ratio; I This is the application coefficient; The initial yield force amplification factor. This is the seismic force reduction factor for the dam simulation test chamber. W The static load of the dam simulation test chamber;

[0159] in Permissible lateral capacity of the dam simulation test chamber and natural period T The relevant calculation formula is:

[0160]

[0161] In the formula denotes the short period and the medium period boundary corner period value, denotes the allowable side volume of the dam simulation test chamber; T denotes the natural vibration period of the dam simulation test chamber.

[0162] Step 4.3: Calculate the load effect of the dam simulation test chamber under combined load.

[0163] The limit state equation is used to analyze and calculate the load effect of the dam simulation test chamber under combined load as follows:

[0164]

[0165] In the formula, g denotes the structure function function; =1,2,…, N is the input variable of the structure function function, including various load actions of the dam simulation test chamber and material properties, geometric parameters of components, N is the number of input variables;

[0166] When the input variables of the structure function function of the dam simulation test chamber are equivalent to two variables of action effect and structural resistance, the stability condition of the dam simulation test chamber is

[0167]

[0168] In the formula, S denotes the action effect of the structure; R denotes the resistance of the structure;

[0169] When the dam simulation test chamber is analyzed under combined load, the Turkstra combination rule is used. First, it is assumed that among all the load effects of the dam simulation test chamber, only one load effect reaches the maximum value, and the other load effects are the time point values, and the combination is performed in turn, wherein the combination that controls the structure is the combination with the minimum structure reliability in the structure reliability analysis. It is assumed that there are n load participating in the combination analysis, the i load corresponding to the time point probability distribution function is , the probability density function of the load , , t denotes the time;

[0170] According to the Turkstra combination rule, n the combination situation is:

[0171]

[0172]

[0173]

[0174] wherein, represents an arbitrary point in time, T D is the design reference period, , ,… respectively represent the total load of the dam simulation test chamber under the first, second, …, and n kind of load combination situation.

[0175] The calculation formula of the stability of the dam simulation test chamber under the combined load situation is:

[0176]

[0177] wherein represents the structure importance coefficient, reflecting the structure safety level; represents the sub-item coefficient of the constant load; represents the load effect of the constant load; represents the sub-item coefficient of the i th live load, represents the combination coefficient of the i th live load; represents the load effect of the i th live load which plays a control role; R ( ) represents the resistance generated by the dam simulation test chamber under the combined load; represents the resistance coefficient of the structure member of the dam simulation test chamber; represents the material performance parameter of the dam simulation test chamber, represents the geometric parameter of the structure member of the dam simulation test chamber.

[0178] Step 5: According to the load combination analysis result obtained in step 4, the maximum displacement of the dam simulation test chamber under the action of different combined loads is calculated;

[0179] Step 5.1: Using the finite element model of the dam simulation test chamber, according to the constant load and live load of the dam simulation test chamber obtained in step 4, the forces and moments resisting deformation generated inside the dam simulation test chamber under the action of different combined loads are calculated, including axial force, shear force, bending moment and torque;

[0180] Step 5.2: The maximum displacement of deformation of the dam simulation test chamber under the action of different combined loads is calculated, including the maximum displacement in X, Y and Z axis directions.

[0181] The deformation displacement of the node of the dam simulation test chamber skeleton structure under the most unfavorable certain combination load in the embodiment is shown in Table 2, wherein the X direction displacement of the node 271 is the maximum under the 16th combination load condition, the Y direction displacement of the node 386 is the maximum, the space displacement of the node 404 is the maximum, and the Y direction deformation displacement of the node 11 is the minimum; the Z direction displacement of the node 459 is the maximum under the 11th combination load condition, and the Z direction deformation displacement of the node 518 is the minimum. In comparison, the deformation of the node 341 reaches the minimum X direction displacement under the 14th combination load condition. The position distribution of the above nodes is shown in Table 2. Figure 7

[0182] Table 2 Comparison table of node deformation displacement of the dam simulation test chamber under combination load

[0183]

[0184] Step 6: the stress field and strain distribution of the dam simulation test chamber are obtained by calculation using the finite element model of the dam simulation test chamber.

[0185] Step 6.1: according to the dead load and live load of the dam simulation test chamber obtained in step 4, the working conditions of different load combinations are established, and the nodes and elements of the finite element model of the dam simulation test chamber are subjected to load.

[0186] Step 6.2: the stress and strain of the dam simulation test chamber under different load combination conditions are numerically simulated and calculated by using the finite element model of the dam simulation test chamber, so as to determine the critical load when the dam simulation test chamber is in stress balance instability and the stress when the structure is in buckling modal shape change.

[0187] Step 6.3: the stress field and strain distribution of the dam simulation test chamber under various working conditions are calculated by using the finite element model of the dam simulation test chamber.

[0188] Step 7: according to the calculation results of step 5 and step 6, it is judged whether the dam simulation test chamber meets the safety requirement? If it meets the requirement, it is ended; if it does not meet the requirement, the structure and parameters of the test chamber are adjusted, and steps 1-6 are executed again.

[0189] In another embodiment of the application, the calculation formula of the stability of the dam simulation test chamber under the combination load condition is:

[0190]

[0191] In the formula, β represents the structure importance coefficient; β1 represents the subitem coefficient of the dead load; β2 represents the load effect of the dead load; β3 represents the load effect of the live load; β4 represents the load effect of the temperature load.​i a subitem coefficient of a live load, a combination coefficient representing the i a combination coefficient representing the a load effect of a control i a load effect of a control R ( ) represents the resistance of the dam simulation test chamber under the combined load; representing the resistance coefficient of the structural member of the dam simulation test chamber; representing the material performance parameters of the dam simulation test chamber, representing the geometric parameters of the structural member of the dam simulation test chamber; representing the combination coefficient of the live load.

[0192] In another embodiment of the present application, a plurality of steel cables are used to bind and fix the dam simulation test chamber. According to the most unfavorable deformation displacement of the dam simulation test chamber obtained in step 5 and the stress field and strain distribution of the dam simulation test chamber under different combined load conditions obtained in step 6, the parameters and number of the steel cables and the anchoring points of the steel cables on the dam simulation test chamber are determined, and the steel cables are added to the finite element model of the dam simulation test chamber. The structural safety and reliability of the dam simulation test chamber bound and fixed by the steel cables are analyzed, and the safety and stability of the dam simulation test chamber are enhanced.

Claims

1. A method for calculating the load of a dam simulation test chamber based on dead load and live load analysis, characterized in that, Includes the following steps: Step 1: Determine the overall weight of the dam simulation test chamber, the weight distribution of the chamber, and the safety design requirements of the test chamber; Obtain the overall structure, cross-sectional information, structural parameters, and material selection of the test chamber; Step 2: Establish the finite element model, i.e., the structural analysis model, of the dam simulation test chamber. Set the materials of the dam simulation test chamber in the finite element model and set the parameters of the finite element model according to the data obtained in Step 1. Step 3: Calculate the elastic modulus, Poisson's ratio, and coefficient of linear expansion of the dam simulation test chamber structure; Step 4: Analyze and calculate the dead load and live load of the dam simulation test chamber, and perform load combination analysis; Step 4.1: Analyze and calculate the dead load of the dam simulation test chamber; Step 4.2: Analyze and calculate the live load of the dam simulation test chamber; Step 4.2.1: Calculate the dynamic loads on personnel inside the dam simulation test chamber; Step 4.2.2: Calculate the wind load borne by the dam simulation test chamber; Step 4.2.3: Analyze and calculate the snow load in the dam simulation test chamber; Step 4.2.4: Analyze and calculate the sediment flow load in the dam simulation test chamber; Step 4.2.5: Analyze and calculate the temperature load of the dam simulation test chamber; Step 4.2.6: Analyze and calculate the seismic load on the dam simulation test chamber; Step 4.3: Calculate the load effects of the dam simulation test chamber under combined loads; Step 5: Based on the load combination analysis results obtained in Step 4, calculate the maximum deformation displacement of the dam simulation test chamber under different load combinations. Step 6: Calculate the stress field and strain distribution of the dam simulation test chamber using the finite element model; Step 7: Based on the calculation results of Step 5 and Step 6, determine whether the dam simulation test chamber meets the structural safety design requirements. If it meets the requirements, the process ends; if it does not meet the requirements, adjust the structure and parameters of the test chamber and repeat Step 1-6.

2. The method for calculating the load of a dam simulation test chamber according to claim 1, characterized in that, Step 2 specifically includes: Step 2.1: Using finite element software, construct a finite element model of the dam simulation test chamber, and select the materials of the dam simulation test chamber in the finite element model according to the design structure and material selection of the dam simulation test chamber, including the steel type and specifications of different parts of the dam simulation test chamber skeleton structure; Step 2.2: Set the cross-sections of the dam simulation test chamber skeleton structure components in the finite element model, including the cross-sections of the main beam, tie rods, and support rods; Step 2.3: Determine the element type of the finite element model of the dam simulation test chamber; Step 2.4: Divide the finite element model of the dam simulation test chamber into elements. Based on the design structure and dimensions of the dam simulation test chamber, determine the nodes and elements of the finite element model of the dam simulation test chamber. Step 2.5: Set the element properties in the finite element model of the dam simulation test chamber. Based on the overall structure, cross-sectional information, structural parameters and material selection data of the dam test chamber obtained in Step 1, add the material and cross-sectional parameters to the elements of the finite element model.

3. The method for calculating the load of a dam simulation test chamber according to claim 1 or 2, characterized in that, Step 3 specifically includes: Step 3.1: Calculate the elastic modulus of the structural components of the dam simulation test chamber; The formula for calculating the elastic modulus is: E = σ / ε In the formula E This represents the elastic modulus of the component material. σ , ε These represent the stress and strain of the component material, respectively. Step 3.2: Calculate the Poisson's ratio of the structural components of the dam simulation test chamber; The formula for calculating Poisson's ratio is: V = ε 1 / ε 2 In the formula V The Poisson's ratio represents the material of the component; ε 1 represents the transverse strain, which is the deformation perpendicular to the load direction. ε 2 represents axial strain, which is the amount of deformation along the load direction; Step 3.3: Calculate the linear expansion coefficient of the structural components of the dam simulation test chamber; The formula for calculating the coefficient of linear expansion is: CTE =(D) L / L 0)*D T In the formula CTE The coefficient of linear expansion of the component material, Δ L This represents the change in the length of the component material when the temperature changes. L 0 represents the initial length of the component material; Δ T It represents the amount of temperature change.

4. The method for calculating the load of a dam simulation test chamber according to claim 3, characterized in that, In step 4.2.1, the formula for calculating the dynamic load on the personnel is: Q = k × γ × L In the formula Q Indicates the dynamic load on personnel. k For the coefficient of dynamic load, γ For the unit weight of dynamic load, L The effective length of the dynamic load.

5. The method for calculating the load of a dam simulation test chamber according to claim 4, characterized in that, In step 4.2.2, the formula for calculating the wind load is: In the formula This represents the unit wind load perpendicular to the surface of the dam simulation test chamber. For wind vibration coefficient, z Indicates altitude, This is the wind load shape coefficient. This is the basic wind pressure value. This represents the coefficient of variation of wind pressure at height.

6. The method for calculating the load of a dam simulation test chamber according to claim 5, characterized in that, In step 4.2.3, the formula for calculating the snow load is: In the formula This represents the snow load value. This is the snow cover distribution coefficient at the top; Basic snow load is the weight of snow per unit area. In the formula h This refers to the depth of the snow cover. p Snow density; g This is the acceleration due to gravity.

7. The method for calculating the load of a dam simulation test chamber according to claim 6, characterized in that, In step 4.2.4, the formula for calculating the sediment flow load is: In the formula F The impact pressure of sediment flow on the dam simulation test chamber. The velocity of the sediment flow. g It is the acceleration due to gravity. α The angle between the impact direction of the sediment flow on the dam simulation test chamber and the impact surface of the dam simulation test chamber. λ The shape factor of the dam simulation test chamber.

8. The method for calculating the load of a dam simulation test chamber according to claim 7, characterized in that, In step 4.2.5, the formula for calculating the temperature load is: T l = CTE *D T * E in T l For the temperature load of the dam simulation test chamber, CTE Δ is the coefficient of linear expansion. T The change in temperature E The elastic modulus of the overall structure of the test chamber.

9. The method for calculating the load of a dam simulation test chamber according to claim 8, characterized in that, In step 4.2.6, the formula for calculating the seismic load is: In the formula V This indicates the seismic load of the dam simulation test chamber. Design spectral acceleration and gravitational acceleration at the site g The ratio; I This is the application coefficient; The initial yield force amplification factor. This is the seismic force reduction factor for the dam simulation test chamber. W The static load of the dam simulation test chamber; in Permissible lateral capacity of the dam simulation test chamber and natural period T The relevant calculation formula is: In the formula This represents the period value that marks the boundary between short-term and medium-term periods. This indicates the permissible lateral capacity of the dam simulation test chamber; T This represents the natural vibration period of the dam simulation test chamber.

10. The method for calculating the load of a dam simulation test chamber according to claim 9, characterized in that, In step 4.3, the load effects of the dam simulation test chamber under combined loads are analyzed and calculated using the following limit state equations: In the formula g ( ) represents a structure function; =1,2,…, N The input variables for the structural function include various loads on the dam simulation test chamber, as well as the material properties and geometric parameters of the components. N The number of input variables; When the input variables of the structural function of the dam simulation test chamber are equivalent to two variables, action effect and structural resistance, the stability condition of the dam simulation test chamber is: In the formula S Indicates the effect of the structure; R Indicates the structural resistance; When performing combined load analysis on the dam simulation test chamber, the Turkstra combination rule is adopted. First, it is assumed that among all load effects in the dam simulation test chamber, only one load effect reaches its maximum value, while the others are point-in-time values. These load effects are combined in turn, with the combination that plays a controlling role being the combination with the lowest structural reliability in the structural reliability analysis. (The last sentence appears to be incomplete and possibly contains errors.) n The load participates in the combination analysis, the first... i load The corresponding point-in-time probability distribution function is Load The probability density function is , t Indicates time; According to Turkstra's combinatorial rules n The possible combinations are: In the formula, Represents any point in time. T D For the design baseline period, , ... They represent the first type, the second type, ... the second type, respectively. n The total load of the dam simulation test chamber under various load combinations; For structural members considering the ultimate limit state of bearing capacity, the stability calculation formula for the dam simulation test chamber under combined loads is as follows: In the formula Indicates the structural importance coefficient; The partial factor representing the dead load; This indicates the load effect of a constant load; Indicates the first i Partial factors for each live load, Indicates the first i Combination coefficient for each live load; Indicates the first that plays a controlling role i The load effect of a live load; R ( ) represents the resistance generated by the dam simulation test chamber under combined loads; This indicates the resistance coefficient of the structural components of the dam simulation test chamber; This indicates the material performance parameters of the dam simulation test chamber. This represents the geometric parameters of the structural components of the dam simulation test chamber.

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