Safety review method for sluice anti-arch bottom plate structure

Abstract

The present invention provides a method for safety review of the inverted arch bottom plate structure of a sluice, comprising: Step 1, obtaining the difference in uneven settlement of adjacent gate piers; Step 2, finite element numerical simulation of the gate chamber; Step 3, safety review of the inverted arch bottom plate. The present invention has the following beneficial effects: 1. A method for safety review of the inverted arch bottom plate structure of a sluice is proposed, which fills the gap in this field and has guiding significance for related projects; 2. When using the finite element method to analyze the internal force of the inverted arch bottom plate, the influence of the measured uneven settlement is considered, so that the internal force analysis results are closer to the actual situation and more accurate; 3. Using the internal force analysis results of the inverted arch bottom plate, a safety review formula for the inverted arch bottom plate is proposed. The formula has a clear physical meaning, can accurately evaluate the safety of the inverted arch bottom plate, and the judgment formula is simple and easy to use.

Description

Technical Field

[0001] The invention belongs to the technical field of water conservancy projects, and in particular relates to a method for safety review of a sluice inverted arch bottom plate structure. Background Art

[0002] Sluice gates are a common hydraulic structure. Conventional sluice gates are flat-bottomed structures, but there are also inverted-arched bottom structures. Around the 1960s, a large number of inverted-arched bottom sluice gates were built in Jiangsu, Zhejiang, Anhui and other provinces in my country. The bottom plate thickness of inverted-arched bottom sluice gates is relatively thin, and only a small amount of steel bars are required, or even no steel bars are required. Therefore, inverted-arched bottom sluice gates can save a lot of building materials, thereby saving investment. According to the "Regulations on the Management of Sluice Safety Appraisal", sluice gates must be regularly subject to comprehensive safety appraisals, and necessary risk elimination and reinforcement must be carried out based on the appraisal results to ensure the safe operation of the sluice gates. The current "Guidelines for Safety Evaluation of Sluice Gates" does not specify a safety review method specifically for inverted-arched bottom plates. The current specification has requirements for the minimum reinforcement ratio of concrete structures in the structural safety review section. Since the inverted arch bottom plate is a concrete component with few or no reinforcements, its reinforcement ratio is far from meeting the requirements of the current code for the minimum reinforcement ratio. According to the code, the structural safety of the inverted arch bottom plate needs to be rated as Class C, which will result in the safety category of the sluice being divided into three or four categories, and the inverted arch bottom plate needs to be reinforced. However, most inverted arch bottom plate sluices have been operating safely for many years. If there are no cracks or other damages on the inverted arch bottom plate of the sluice, it is bound to be uneconomical and unreasonable to carry out risk removal and reinforcement. Summary of the invention

[0003] 1. Technical issues to be solved

[0004] The embodiment of the present application provides a method for safety review of the inverted arch bottom plate structure of a sluice, which provides a scientific and reasonable method for safety review of the inverted arch bottom plate, avoids unnecessary risk elimination and reinforcement, and fills the gap in this field.

[0005] (II) Technical solution

[0006] The embodiment of the present application provides a method for safety review of a sluice inverted arch bottom plate structure, comprising:

[0007] Step 1, obtain the difference of uneven settlement of adjacent gate piers;

[0008] Step 2, finite element numerical simulation of the lock chamber;

[0009] Step 3: Safety review of the arch bottom plate.

[0010] Among them, Step 1, obtaining the difference in uneven settlement of adjacent gate piers, includes:

[0011] Use a precision level to obtain the elevation Z of each pier top i, the absolute value of the difference in elevation between adjacent pier tops ABS (Z i+1 -Z i ) is the differential settlement value.

[0012] Among them, Step 2, finite element numerical simulation of the lock chamber, includes:

[0013] (1) Establish a finite element model based on the structural dimensions, topography, and geological conditions of the lock chamber;

[0014] (2) Input material parameters of each part of the model, set boundary conditions, and apply loads;

[0015] (3) The uneven settlement between adjacent gate piers obtained in Step 1 is input as the forced displacement boundary condition;

[0016] (4) Perform finite element calculation to obtain the internal force results of the anti-arch bottom plate.

[0017] Among them, the uneven settlement between adjacent gate piers obtained in Step 1 is input as the forced displacement boundary condition, including:

[0018] Analyze and compare the observed gate pier top elevation value Z i , select the maximum value MAX (Z i ), maximum value MAX (Z i ) is set to zero, and the vertical forced displacements of other piers are set to (MAX(Z i )-Z i ), the direction is vertically downward.

[0019] Among them, Step 3, anti-arch bottom plate safety review, includes:

[0020] (1) Compare the maximum tensile stress max_σ in the maximum principal stress of the anti-arch bottom plate t and concrete tensile design value f t .

[0021] (2) Take the section where the maximum principal stress of the internal force of the arch bottom plate is located, and compare the magnitudes of the first calculation formula and the second calculation formula. The first calculation formula is: ave_σ t ×b×h t , the second calculation formula is (A s ×f y ) / K, where ave_σ t is the average stress in the tensile zone at the location of maximum tensile stress, h t is the height of the tension zone, b is the calculated width, A s To calculate the tensile reinforcement area within the width b, f y is the design value of the tensile strength of the steel bar used, K is the safety factor, and its value range is 1 to 1.35;

[0022] The physical meaning of the first calculation formula is to calculate the total stress in the tensile zone within the width. s ×f y ) is the physical meaning of calculating the tensile bearing capacity of the tensile steel bars within the width.

[0023] Among them, when max_σ t <f t The inverted arch bottom plate will not crack under the action of various loads, and the inverted arch bottom plate with few reinforcements will not affect the safety of the gate chamber structure. The safety grade of the inverted arch bottom plate structure can be rated as Class B.

[0024] Among them, when max_σ t >=f t , and ave_σ t ×b×h t <(A s ×f y ) / K, the inverted arch floor may crack under the action of various loads, but the steel bars in the tension zone will not fail immediately. In this case, it is necessary to further analyze the necessity of reinforcing the inverted arch floor. If the condition with the largest internal force of the floor can be avoided during operation, the safety grade of the inverted arch floor structure can be rated as B. If it is unavoidable, the safety grade of the inverted arch floor structure can be rated as C.

[0025] Among them, when max_σ t >=f t , and ave_σ t ×b×h t >=(A s ×f y ) / K, the anti-arch bottom plate may crack under the action of various loads, and the steel bars in the tension zone may fail immediately. In this case, the anti-arch bottom plate poses a greater threat to the safety of the gate chamber structure. The safety grade of the anti-arch bottom plate structure can be rated as C, and it is recommended to take effective measures to reinforce the anti-arch bottom plate.

[0026] (III) Beneficial effects

[0027] The safety review method for the sluice inverted arch bottom plate structure of the embodiment of the present application has the following beneficial effects:

[0028] The safety review method of the inverted arch bottom plate structure of the water gate of the present application includes: Step 1, obtaining the difference of uneven settlement of adjacent gate piers; Step 2, finite element numerical simulation of the gate chamber; Step 3, safety review of the inverted arch bottom plate. The present invention has the following beneficial effects: 1. A safety review method of the inverted arch bottom plate structure of a water gate is proposed, which fills the gap in this field and has guiding significance for related projects; 2. When using the finite element method to analyze the internal force of the inverted arch bottom plate, the influence of the measured uneven settlement is considered, so that the internal force analysis results are closer to the actual situation and more accurate; 3. Using the internal force analysis results of the inverted arch bottom plate, a safety review formula for the inverted arch bottom plate is proposed. The formula has a clear physical meaning, can accurately evaluate the safety of the inverted arch bottom plate, and the judgment formula is simple and easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the overall steps of the safety review method for the anti-arch bottom plate structure of the sluice gate in this application;

[0030] Figure 2 This is the safety review flow chart for the arch bottom plate;

[0031] Figure 3 It is the finite element model of the inverted arch bottom sluice;

[0032] Figure 4 It is the maximum principal stress cloud diagram of the anti-arch bottom plate;

[0033] Figure 5 This is a schematic diagram of the internal force calculation of the reinforced section;

[0034] Figure 6 This is a schematic diagram of the cross section of a conventional flat-bottomed sluice gate;

[0035] Figure 7 This is a schematic diagram of the cross section of the inverted arch bottom sluice. DETAILED DESCRIPTION

[0036] like Figure 1-7 As shown, the purpose of the present invention is to provide a method for safety review of the inverted arch bottom plate structure of a sluice, to provide a scientific and reasonable method for safety review of the inverted arch bottom plate, to avoid unnecessary risk removal and reinforcement, and to fill the gap in this field.

[0037] In order to achieve the above object, the present invention proposes a safety review method for a sluice inverted arch bottom plate structure, which comprises: Step 1, obtaining the difference in uneven settlement of adjacent gate piers; Step 2, finite element numerical simulation of the gate chamber; Step 3, safety review of the inverted arch bottom plate.

[0038] In the above Step 1, a precision level can be used to obtain the elevation Z of each pier top. i , the absolute value of the difference in elevation between adjacent pier tops ABS (Z i+1 -Z i) is the difference in uneven settlement. The inverted arch bottom plate structure is very sensitive to deformation, and a small deformation can cause a large stress inside the inverted arch structure. In an inverted arch bottom plate sluice, adjacent piers are prone to uneven settlement, which has a great impact on the internal force of the bottom plate. Therefore, when reviewing the safety of the inverted arch bottom plate structure, the impact of this part should be considered.

[0039] In the above Step 2, the specific steps of the finite element numerical simulation analysis of the gate chamber are as follows: (1) Establish a finite element model based on the structural dimensions, topography, and geological conditions of the gate chamber; (2) Input the material parameters of each part of the model, set boundary conditions, and apply loads; (3) Input the uneven settlement between adjacent gate piers obtained in Step 1 as the forced displacement boundary condition; (4) Perform finite element calculation to obtain the internal force results of the anti-arch bottom plate.

[0040] The specific method of inputting uneven settlement as the forced displacement boundary condition in the above step (3) is: Analyze and compare the observed gate pier top elevation value Z i , select the maximum value MAX (Z i ), maximum value MAX (Z i ) is set to zero, and the vertical forced displacements of other piers are set to (MAX(Z i )-Z i ), in a vertically downward direction. The prior art does not mention the consideration of the influence of uneven settlement between adjacent gate piers during the analysis process, and this factor has a great influence on the internal force of the anti-arch bottom plate. The above consideration of uneven settlement and the specific application method when analyzing the internal force of the anti-arch bottom plate using finite element analysis are original to the present invention.

[0041] In the above Step 3, the safety review of the arch bottom plate mainly uses the internal force results of the arch bottom plate obtained in Step 2, especially the maximum principal stress value. The specific method is as follows:

[0042] (1) Compare the maximum tensile stress (max_σt) in the maximum principal stress of the anti-arch bottom plate with the concrete tensile design value (f t ).

[0043] (2) If necessary, take the section where the maximum principal stress of the internal force of the arch bottom plate is located, and further compare the formula (ave_σ t ×b×h t ) and formula ((A s ×f y ) / K) value, where ave_σ t is the average stress in the tensile zone at the location of maximum tensile stress, h t is the height of the tension zone, b is the calculated width, A s To calculate the tensile reinforcement area within the width b, f yis the design value of the tensile strength of the steel bar used, and K is the safety factor (1 to 1.35). (Note: The comparison formula in this part is original to the present invention)

[0044] In the above step (1), the concrete tensile design value (f t ) Concrete parameters obtained from on-site testing can also be used.

[0045] In the above step (2), the formula (ave_σ t ×b×h t The physical meaning of ) is to calculate the total stress in the tensile zone within the width. s ×f y The physical meaning of ) is to calculate the tensile bearing capacity of the tensile reinforcement within the width. s ×f y ) / K) in which K is taken as 1 to 1.35 according to the importance of the project in order to consider a certain safety margin.

[0046] By comparing steps (1) and (2), the following situations may occur:

[0047] Case 1: Maximum principal stress in the internal force of the arch bottom plate, max_σ t <f t At this time, the anti-arch bottom plate will not crack under the action of various loads, and the anti-arch bottom plate with few reinforcements will not affect the safety of the lock chamber structure. The anti-arch bottom plate structure safety grading can be rated as Class B. (Note: The current sluice code divides structural safety into three levels: Class A: good condition, Class B: certain quality defects do not affect safety, and Class C: does not meet the standard requirements.)

[0048] Case 2: Maximum principal stress in the internal force of the arch bottom plate, max_σ t >=f t , and ave_σ t ×b×h t <(A s ×f y ) / K, at this time, the inverted arch floor may crack under the action of various loads, but the steel bars in the tension zone will not fail immediately. In this case, it is necessary to further analyze the necessity of reinforcing the inverted arch floor. If the working condition with the maximum internal force of the floor can be avoided during operation, the safety grade of the inverted arch floor structure can be rated as B. If it is unavoidable, the safety grade of the inverted arch floor structure can be rated as C.

[0049] Case 3: Maximum principal stress in the internal force of the arch bottom plate, max_σ t >=f t , and ave_σ t ×b×h t >=(A s ×f y) / K, at this time, the anti-arch bottom plate may crack under the action of various loads, and the steel bars in the tension zone may fail immediately. In this case, the anti-arch bottom plate poses a greater threat to the safety of the gate chamber structure. The safety grade of the anti-arch bottom plate structure can be rated as C, and it is recommended to take effective measures to reinforce the anti-arch bottom plate.

[0050] The present invention has the following beneficial effects:

[0051] 1. A safety review method for the anti-arch bottom plate structure of a sluice is proposed, which fills the gap in this field and has guiding significance for related projects;

[0052] 2. When using the finite element method to analyze the internal forces of the anti-arch bottom plate, the influence of the measured uneven settlement is taken into account, making the internal force analysis results closer to the actual situation and more accurate;

[0053] 3. Using the internal force analysis results of the anti-arch floor, a safety review formula for the anti-arch floor is proposed. The formula has a clear physical meaning and can accurately evaluate the safety of the anti-arch floor. The judgment formula is simple and easy to use.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for safety review of a sluice arch bottom plate structure, characterized in that: include: Step 1, obtain the difference of uneven settlement of adjacent gate piers; Step 2, finite element numerical simulation of the lock chamber; Step 3: Safety review of the arch bottom plate; including: (1) Compare the maximum tensile stress max_σ in the maximum principal stress of the anti-arch bottom plate t and concrete tensile design value f t ; (2) Take the section where the maximum principal stress of the internal force of the arch bottom plate is located, and compare the magnitudes of the first calculation formula and the second calculation formula. The first calculation formula is: ave_σ t ×b×h t , the second calculation formula is (A s ×f y ) / K, where ave_σ t is the average stress in the tensile zone at the location of maximum tensile stress, h t is the height of the tension zone, b is the calculated width, A s To calculate the tensile reinforcement area within the width b, f y is the design value of the tensile strength of the steel bar used, K is the safety factor, and its value range is 1 to 1.35; The physical meaning of the first calculation formula is to calculate the total stress in the tensile zone within the width. s ×f y ) is the physical meaning of calculating the tensile bearing capacity of the tensile reinforcement within the width; When max_σ t <f t When the inverted arch bottom plate is under the action of various loads, it will not crack, and the inverted arch bottom plate with few reinforcements will not affect the safety of the lock chamber structure. The safety rating of the inverted arch bottom plate structure is rated as Class B. When max_σ t >=f t , and ave_σ t ×b×h t <(A s ×f y ) / K, the inverted arch floor may crack under the action of various loads, but the steel bars in the tension zone will not fail immediately. In this case, it is necessary to further analyze the necessity of reinforcing the inverted arch floor. If the condition that makes the internal force of the floor the largest can be avoided during operation, the safety classification of the inverted arch floor structure is rated as Class B. If it is unavoidable, the safety classification of the inverted arch floor structure is rated as Class C. When max_σ t >=f t , and ave_σ t ×b×h t >=(A s ×f y ) / K, the anti-arch bottom plate may crack under the action of various loads, and the steel bars in the tension zone may fail immediately. In this case, the anti-arch bottom plate poses a greater threat to the safety of the gate chamber structure. The anti-arch bottom plate structure safety grade is rated as C, and effective measures are taken to reinforce the anti-arch bottom plate.

2. The method for safety review of the sluice inverted arch bottom plate structure according to claim 1 is characterized in that: Step 1: Obtain the difference in uneven settlement of adjacent piers, including: Use a precision level to obtain the elevation Z of each pier top i , the absolute value of the difference in elevation between adjacent pier tops ABS (Z i+1 -Z i ) is the differential settlement value.

3. The method for safety review of the sluice inverted arch bottom plate structure according to claim 1 or 2, characterized in that: Step 2: Finite element numerical simulation of the lock chamber, including: (1) Establish a finite element model based on the structural dimensions, topography, and geological conditions of the lock chamber; (2) Input material parameters of each part of the model, set boundary conditions, and apply loads; (3) The uneven settlement between adjacent gate piers obtained in Step 1 is input as the forced displacement boundary condition; (4) Perform finite element calculation to obtain the internal force results of the anti-arch bottom plate.

4. The method for safety review of the sluice inverted arch bottom plate structure according to claim 3 is characterized in that: The uneven settlement between adjacent piers obtained in Step 1 is input as the forced displacement boundary condition, including: Analyze and compare the observed gate pier top elevation value Z i , select the maximum value MAX (Z i ), maximum value MAX (Z i ) is set to zero, and the vertical forced displacements of other piers are set to (MAX(Z i )-Z i ), the direction is vertically downward.

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