Method for determining concrete drop parameters
By calculating the concrete falling speed through simulation experiments and the law of conservation of energy, adjusting the cylinder parameters and setting up buffer devices, the problem of unclear matching relationship between concrete falling speed and cylinder parameters was solved, thus improving construction quality and precision.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI CONSTRUCTION FIRST CONSTRUCTION (GROUP) CO LTD
- Filing Date
- 2026-04-27
- Publication Date
- 2026-06-30
Smart Images
Figure CN122307075A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of building construction technology, and in particular to a method for determining concrete falling parameters. Background Technology
[0002] During the concrete pouring process, it is necessary to effectively control the concrete falling speed to avoid segregation of the concrete mixture due to excessive falling speed. At the same time, it is necessary to reduce the impact of high-speed material flow on the steel reinforcement cage and formwork, and prevent excessive air trapped inside the concrete from forming defects such as pores and looseness, thereby ensuring the density, mechanical properties and structural safety of the components.
[0003] In current engineering practice, tremie pipes are commonly used for concrete pouring. Concrete is slowly poured through the inner cavity of the tremie pipe, effectively reducing the free fall height and improving pouring uniformity to some extent. However, current technology does not clearly define the matching relationship between the concrete falling speed and the tremie pipe parameters, nor does it clarify the impact of concrete falling energy loss on the falling speed. This leads construction workers to determine the number and arrangement of tremies based solely on experience during on-site operations, and subjectively select the concrete slump. This can easily result in problems such as uncontrolled concrete pouring speed and poor segregation control, making it difficult to consistently guarantee the construction quality of components.
[0004] Therefore, there is an urgent need for a method to determine the parameters of concrete drop in order to solve the above problems. Summary of the Invention
[0005] The purpose of this invention is to provide a method for determining concrete drop parameters, which clarifies the quantitative relationship between the height of the cylinder, the number of cylinders, and energy loss, significantly improving the accuracy of the concrete drop parameter calculation results and ensuring the quality of structural construction.
[0006] To achieve this objective, the present invention adopts the following technical solution: A method for determining concrete drop parameters is provided, including the following steps: S1. Conduct multiple sets of simulation tests based on the construction conditions. The simulation tests include pouring concrete into the inner cavity of the duct structure and measuring the test velocity v of the concrete flowing out from the bottom of the duct structure. i ; The cascade structure consists of multiple connected cylindrical sections. In multiple sets of simulation tests, the connection method of any two connected cylindrical sections in each set of cascade structures is the same, the inner diameter D of the cylindrical sections in each set of cascade structures is the same, the number n of the cylindrical sections in each set of cascade structures is different, and the height h of the cylindrical sections in each set of cascade structures is different. S2. Based on the formula v derived from the law of conservation of energy i =[2g(H-nδ j )] 1 / 2Calculate the test height δ lost by the concrete as it passes through one section of the cylinder in each set of simulation tests. j And the test height δ of multiple sets of simulation experiments j The average value is set as the single-section loss height δ; Where g is the acceleration due to gravity, H is the pouring height of the concrete, H=n×h+△h, and △h is the free fall height of the concrete from the bottom of the duct structure to the pouring surface; S3. Determine the number n and height h of the cylinders used on the construction site based on the construction conditions, and apply the formula v=[2g(H-nδ)]. 1 / 2 Calculate the falling velocity v of the concrete; Alternatively, determine the falling speed v and the number of cylinders n based on the construction conditions, and apply the formula v=[2g(H-nδ)]. 1 / 2 Calculate the pouring drop height H Alternatively, the falling speed v and the pouring height H can be determined based on the construction conditions, and the formula v=[2g(H-nδ)] can be used. 1 / 2 Calculate the number n of cylinders at the construction site.
[0007] Optionally, in step S1, each group of simulation experiments is repeated multiple times to obtain multiple experimental speeds v. i .
[0008] Optionally, step S2 specifically includes the following steps: S21. Calculate multiple test speeds v obtained from a set of simulation tests. i average velocity v k ; S22, Average velocity v k Substituting the number of cylinders n and the height h of the cylinders in the corresponding group into the formula v k =[2gn(h-δ j )] 1 / 2 In the middle, the test height δ of the corresponding group is calculated. j ; S23. Repeat steps S21 and S22 until multiple test heights δ are obtained. j ; S24. Calculate multiple test heights δ j The average value is used to obtain the single-section loss height δ.
[0009] Optionally, in step S3, the falling velocity v is calculated; Step S3 is followed by the following steps: S4. Determine if the falling speed v is greater than the limit speed; if yes, adjust the number of cylinders n, the height h of the cylinders h, and / or the slump of the concrete; if no, proceed with the concrete pouring operation. The specified speed is the critical maximum speed at which the concrete does not segregate during its descent.
[0010] Optional, the speed limit is 3.0 m / s.
[0011] Optionally, in step S4, if the falling speed v is greater than the limited speed, and the number of cylinders n, the height of the cylinder h, and the slump of the concrete are all fixed, a buffer device is set at the lower cylinder opening of the cascade structure. The buffer device is used to buffer the concrete to reduce the falling speed v.
[0012] Optionally, in step S2, according to the law of conservation of energy, the gravitational potential energy mgH and the kinetic energy mv of the falling concrete are obtained. 2 The formula relating / 2 to the energy loss of concrete mgnδ is: mgH = mv 2 / 2+mgnδ; where m is the mass of the concrete; According to the formula mgH=mv 2 / 2+mgnδ derives v=[2g(H-nδ)] 1 / 2 .
[0013] Optionally, in step S1, when pouring concrete into the inner cavity of the cascade structure, the concrete is controlled to flow in a state where the inner cavity cross-section is not completely filled.
[0014] Optionally, in step S1, the concrete mix proportion used in the simulation test is the same as that used in the actual construction, and the concrete mix proportion used in multiple simulation tests is the same; the slump of the concrete used in the simulation test is the same as that used in the actual construction, and the slump of the concrete used in multiple simulation tests is the same.
[0015] Optionally, in step S1, the connection methods for any two connected cylinders include lap joint connection and flange connection.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for determining concrete drop parameters. In actual construction, the concrete drop speed is generally adjusted by changing the number of cylinders (n) and the height of the cylinders (h). Therefore, in step S1, during multiple simulation tests, the inner diameter D of the cylinders and the connection method of the cylinders are kept constant, while the number of cylinders (n) and the height of the cylinders (h) are set as variables. The simulation tests in step S1 are conducted strictly according to the construction conditions, which not only simplifies the simulation process but also accurately reflects the on-site construction conditions. The resulting test speed v...i It can be directly adapted to practical engineering applications. Step S2, based on the law of conservation of energy, incorporates the experimental height δ into the calculation formula. j This method fully considers the energy loss during the concrete drop process. The single-section loss height δ obtained through multiple simulation tests accurately reflects the actual movement of the concrete, improving the accuracy of the concrete drop parameter calculations. Based on the calculation results of step S2, the concrete drop velocity v calculated in step S3 accurately reflects the actual movement of the concrete, effectively avoiding problems such as uncontrolled concrete pouring speed and poor segregation control, thus improving the construction quality of the building structure. Furthermore, the formula in step S3 clarifies the quantitative relationship between the cylinder height h, the number of cylinders n, and the concrete drop velocity v, providing a scientific basis for determining the concrete drop velocity v in actual construction, further improving construction reliability and structural forming quality. In actual construction, if the concrete drop velocity v is known, the concrete drop parameter determination method provided by this invention can also be applied to the selection and determination of the pouring drop height H and the number of cylinders n, effectively avoiding the problem of excessively adding cylinders to reduce segregation during construction, thereby reducing construction costs. Attached Figure Description
[0017] Figure 1 A schematic diagram of the tremie pipe structure to which the concrete falling parameter determination method provided by the present invention is applicable; Figure 2 A flowchart of the first method for determining concrete drop parameters provided by the present invention; Figure 3 A flowchart of the second method for determining concrete drop parameters provided by the present invention; Figure 4 A flowchart of the third method for determining concrete drop parameters provided by the present invention.
[0018] In the picture: 100. String structure; 110. String body; 200. Casting surface. Detailed Implementation
[0019] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.
[0020] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0022] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.
[0023] like Figures 1 to 4 As shown, this embodiment provides a method for determining concrete drop parameters, which clarifies the quantitative relationship between the height of the cylinder 110, the number of cylinders 110, and energy loss, significantly improving the accuracy of the concrete drop parameter calculation results and ensuring the quality of structural construction.
[0024] See Figure 1 The method for determining the concrete drop parameters includes the following steps: S1. Conduct multiple sets of simulation tests based on the construction conditions. The simulation tests include pouring concrete into the inner cavity of the duct structure 100 and measuring the test velocity v of the concrete flowing out from the bottom of the duct structure 100. i The cascade structure 100 includes multiple connected cylindrical sections 110. In multiple sets of simulation tests, the connection method of any two connected cylindrical sections 110 in each set of cascade structures 100 is the same, the inner diameter D of the cylindrical sections 110 in each set of cascade structures 100 is the same, the number n of the cylindrical sections 110 in each set of cascade structures 100 is different, and the height h of the cylindrical sections 110 in each set of cascade structures 100 is different.
[0025] The concrete falling parameter determination method provided in this embodiment typically adjusts the concrete falling speed during actual construction by changing the number n and height h of the cylinder 110. Therefore, in step S1, during multiple simulation tests, the inner diameter D and connection method of the cylinder 110 are kept constant, while the number n and height h of the cylinder 110 are set as variables. The simulation test in step S1 is conducted strictly according to the construction conditions, which not only simplifies the simulation process but also accurately reflects the on-site construction conditions. The resulting test speed v i It can be directly adapted to actual engineering applications.
[0026] S2. Based on the formula v derived from the law of conservation of energy i =[2g(H-nδ j )] 1 / 2 Calculate the test height loss δ of the concrete as it passes through one section of the cylinder 110 in each set of simulation tests. j And the test height δ of multiple sets of simulation experiments j The average value is set as the single-section loss height δ; where g is the gravitational acceleration, H is the pouring drop height of the concrete, H=n×h+△h, and △h is the free drop height of the concrete from the lower end of the duct structure 100 to the pouring surface 200.
[0027] The method for determining concrete drop parameters provided in this embodiment introduces the test height δ in step S2 of the calculation formula based on the law of conservation of energy. j This fully considers the energy loss during the concrete drop process, and the single-section loss height δ obtained through multiple sets of simulation tests can truly reflect the actual movement of the concrete, thus improving the accuracy of the concrete drop parameter calculation results.
[0028] During the test, the concrete loses some energy as it passes through a 110mm section of the cylindrical shell. The test height δ... j The height value is calculated from the energy loss mentioned above; the single-section loss height δ is the height value calculated from the average value of multiple energy losses in multiple simulation tests.
[0029] For example, the free fall height △h ≤ 2m, and the specific value is determined according to the specific construction conditions.
[0030] S3, see reference Figure 1 and Figure 2 The quantity n and height h of the cylinder 110 used at the construction site are determined based on the construction conditions, and the formula v=[2g(H-nδ)] is applied. 1 / 2 Calculate the falling velocity v of the concrete; or, refer to... Figure 1 and Figure 3The falling speed v and the number n of the cylinder 110 are determined according to the construction conditions, and the formula v=[2g(H-nδ)] is used. 1 / 2 Calculate the pouring height H; or refer to Figure 1 and Figure 4 The falling speed v and the pouring height H are determined based on the construction conditions, and the formula v=[2g(H-nδ)] is used. 1 / 2 Calculate the number n of cylinders 110 at the construction site.
[0031] The concrete drop parameter determination method provided in this embodiment, based on the calculation results of step S2, allows the concrete drop velocity v obtained through calculation in step S3 to accurately reflect the actual movement state of the concrete. This effectively avoids problems such as uncontrolled concrete pouring speed and poor segregation control, thus improving the construction quality of the building structure. Furthermore, the formula in step S3 clarifies the quantitative relationship between the height h of the cylinder 110, the number n of cylinders 110, and the concrete drop velocity v, providing a scientific basis for determining the concrete drop velocity v in actual construction and further improving construction reliability and structural forming quality. In actual construction, if the concrete drop velocity v is known, the concrete drop parameter determination method provided in this embodiment can also be applied to the selection and determination of the pouring drop height H and the number n of cylinders 110. This effectively avoids the problem of excessively adding cylinders 110 during construction to reduce segregation, thereby reducing construction costs.
[0032] For example, when it is necessary to calculate the number n of cylinders 110, the formula v=[2g(H-nδ)] is used. 1 / 2 The calculated value may not be an integer. Therefore, when calculating the number n of the cylinder body 110, the number n of the cylinder body 110 must be greater than the calculated value, and the number n of the cylinder body 110 must be an integer.
[0033] For example, when it is necessary to calculate the number n of cylinders 110, given that the height h of the cylinders 110 of the existing cascade structure 100 is mostly a standardized specification with a relatively limited range of specifications, under the condition that the pouring drop height H is fixed, a suitable height h of cylinder 110 can be selected according to the specific construction conditions, thereby facilitating the calculation of the number n of cylinders 110.
[0034] For example, when it is necessary to calculate the pouring height H, the formula is v=[2g(H-nδ)]. 1 / 2 The derivation yields H=(v 2 +2gδ) / (2g), and then by substituting the quantity n and the falling speed v into the above formula, the pouring height H can be obtained.
[0035] In some embodiments, in step S1, when pouring concrete into the inner cavity of the tremie pipe structure 100, the concrete is controlled to flow in a state where the inner cavity cross-section of the cylinder 110 is not completely filled. In actual engineering, when concrete is transported through the tremie pipe structure 100, it is often in a non-full-pipe flow state where the cross-section of the cylinder 110 is not completely filled. In order to truly reflect the falling velocity v, flow law and segregation characteristics of concrete in the tremie pipe structure 100, the concrete is controlled to flow in a state where the inner cavity cross-section of the cylinder 110 is not completely filled during the simulation test.
[0036] In some embodiments, in step S1, the concrete mix proportion used in the simulation test is the same as that used in actual construction, and the concrete mix proportions used in multiple simulation tests are all the same; the slump of the concrete used in the simulation test is the same as that used in actual construction, and the slump of the concrete used in multiple simulation tests is also the same. This operation can further effectively control the variables during the simulation test, ensuring that only the height h and the number n of the cylinder 110 differ between each group of simulation tests, thus improving the accuracy of the simulation test results. Moreover, the concrete mix proportion and slump directly determine its cohesiveness, fluidity, and falling motion pattern. Maintaining consistency between the simulation test and actual construction can eliminate test errors caused by differences in material properties, ensuring that the test data from the simulation test can accurately guide actual construction.
[0037] In some embodiments, in step S1, the connection method between any two connected cylinders 110 includes lap joint connection and flange connection. In actual construction sites, lap joint or flange connection is often used between cylinders 110. This type of connection can create local steps, gaps, or abrupt changes in pipe diameter, which in turn affects the flow pattern, flow velocity, and slurry loss of concrete. Using the same lap joint or flange connection method in the simulation test can reproduce the flow resistance and boundary conditions brought about by the actual connection method of the cylinders 110, improve the authenticity and reliability of the test data, and make the test results more meaningful for engineering guidance.
[0038] Optionally, in step S1, each group of simulation experiments is repeated multiple times to obtain multiple experimental speeds v. i By repeatedly testing each set of simulations, the interference of accidental factors such as experimental operation, material fluctuations, and environmental changes on the experimental results can be eliminated, and the statistically regular experimental speed v can be obtained. i This will enhance the credibility and stability of the experimental conclusions.
[0039] In this embodiment, step S2 specifically includes the following steps: S21. Calculate multiple test speeds v obtained from a set of simulation tests. i average velocity v k .
[0040] For example, a total of N1 sets of simulation experiments were conducted, k=1, 2, ..., N1; the simulation experiment of the x-th set was repeated N2 times, i=1, 2, ..., N2, v k =(v1+v2+…+v N2 ) / N2.
[0041] S22, Average velocity v k Substituting the quantity n of the corresponding group of cylinder 110 and the height h of the corresponding group of cylinder 110 into the formula v k =[2g(H-nδ j )] 1 / 2 In the middle, the test height δ of the corresponding group is calculated. j .
[0042] For example, a total of N1 sets of simulation experiments were conducted, j=1,2,…,N1; the experimental height δ of the x-th simulation experiment was… j =(2gH-v k 2 ) / 2gn.
[0043] S23. Repeat steps S21 and S22 until multiple test heights δ are obtained. j .
[0044] For example, a total of N1 sets of simulation experiments were conducted. In step S23, steps S21 and S22 were repeated a total of N1-1 times, and a total of N1 experimental heights δj were obtained.
[0045] S24. Calculate multiple test heights δ j The average value is used to obtain the single-section loss height δ.
[0046] For example, a total of N1 sets of simulation experiments were conducted, δ=(δ1+δ2+…+δ N1 ) / N1.
[0047] Optionally, in step S2, according to the law of conservation of energy, the gravitational potential energy mgH and the kinetic energy mv of the falling concrete are obtained. 2 The formula relating / 2 to the energy loss of concrete mgnδ is: mgH = mv 2 / 2+mgnδ; where m is the mass of the concrete; according to the formula mgH=mv 2 / 2+mgnδ derives v=[2g(H-nδ)] 1 / 2 .
[0048] According to the law of conservation of energy, the gravitational potential energy of falling concrete is equal to the sum of its kinetic energy and the energy lost, i.e., mgH = mv. 2 / 2+mgH loss , where H lossLet H be the total height lost by the concrete as it flows through the cascade structure 100. Based on this, assuming that the height loss δ of the concrete in each section of the cascade 110 is the same, then H... loss =n×δ,mgH=mv 2 / 2+mgnδ. Then, removing the common physical quantity mg from both sides of the equation, we get H=v 2 / (2g)+nδ;Simplifying, we get v=[2g(H-nδ)] 1 / 2 .
[0049] Optionally, see Figure 1 and Figure 2 In step S3, the falling speed v is calculated. After step S3, the following steps are also included: S4, determine whether the falling speed v is greater than the limit speed; if yes, adjust the number n of the cylinder body 110 of the duct structure 100, the height h of the cylinder body 110 of the duct structure 100 and / or the slump of the concrete; if no, carry out the concrete pouring operation; wherein, the limit speed is the critical maximum speed at which the concrete does not segregate during the falling process.
[0050] When the falling velocity v exceeds the limit, it indicates that the concrete segregation will occur when the tremie pipe structure 100 selected according to the current scheme is used for concrete pouring. This means the current tremie pipe structure 100 does not meet the construction requirements. Therefore, it is necessary to adjust the number n of the pipe bodies 110, the height h of the pipe bodies 110, and / or the slump of the concrete in the current tremie pipe structure 100 to meet the construction requirements and ensure the quality of the building structure construction. By adjusting the slump of the concrete, its cohesion, internal friction resistance, and flow properties can be changed, thereby altering its falling acceleration and final falling velocity v within the tremie pipe structure 100.
[0051] Specifically, according to the formula v=[2g(H-nδ)] 1 / 2 It can be seen that when at least one of the number of cylinders 110 n and the height of cylinders 110 h decreases, the pouring drop height H will decrease, and the falling speed v will decrease accordingly, so that the falling speed v can be less than the limit speed.
[0052] For example, the falling speed is limited to 3.0 m / s. Limiting the concrete falling speed v to within 3.0 m / s can avoid problems such as aggregate segregation, air inclusion, and impact disturbance to the formwork reinforcement caused by excessive falling speed, thus ensuring the quality of pouring.
[0053] In some embodiments, in step S4, if the falling speed v is greater than the limit speed, and the number n of cylinders 110, the height h of cylinders 110, and the slump of concrete are all fixed, a buffer device is set at the lower cylinder opening of the cassette structure 100. The buffer device is used to buffer the concrete to reduce the falling speed v, so that the falling speed v can be less than the limit speed.
[0054] Specifically, when the buffer device uses a deceleration baffle, guide vane, or spiral guide plate, it reduces the falling speed v by changing the flow path of the concrete.
[0055] Specifically, when the buffer device uses a flexible buffer cone or a rubber buffer sleeve, it can flexibly decelerate the concrete.
[0056] In some embodiments, in step S4, if the falling speed v is greater than the predetermined speed, and the number n of cylinders 110, the height h of cylinders 110, and the slump of concrete are all fixed, the inner diameter D of the cylinders 110 is adjusted. When the inner diameter D of the cylinders 110 changes, the single-section loss height δ will change, and thus the falling speed v will change accordingly, so that the falling speed v can be less than the predetermined speed.
[0057] Optionally, after the construction of multiple engineering projects, a database of concrete rheological parameters, inner diameter D of cylinder 110, connection method between two cylinders 110, and single-section loss height δ can be established. Then, during the construction of other engineering projects, the single-section loss height δ of this project can be determined by directly selecting a suitable single-section loss height δ from the database. That is, steps S1 and S2 do not need to be executed, and step S3 can be executed directly, which improves the efficiency of determining concrete drop parameters and reduces the operational difficulty of determining concrete drop parameters.
[0058] Among them, concrete rheological parameters include concrete mix proportions and concrete slump.
[0059] Specifically, based on the data stored in the database, empirical formulas can be established between concrete rheological parameters, the inner diameter D of the cylinder 110, and the single-section loss height δ using regression analysis methods (such as linear regression and nonlinear regression) or machine learning methods (such as random forest, support vector regression, or neural networks). A mapping relationship can also be established between concrete rheological parameters, the inner diameter D of the cylinder 110, the single-section loss height δ, and the connection method between the two cylinders 110.
[0060] For example, the parameters in the relational formula can be obtained from the experimental height δ of multiple sets of simulation experiments. j The fit was determined.
[0061] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for determining concrete drop parameters, characterized in that, Includes the following steps: S1. Conduct multiple sets of simulation tests based on the construction conditions. The simulation tests include pouring concrete into the inner cavity of the duct structure and measuring the test velocity v of the concrete flowing out from the bottom of the duct structure. i ; The cascade structure includes multiple connected cylindrical sections. In the multiple sets of simulation tests, the connection method of any two connected cylindrical sections in each set of the cascade structure is the same, the inner diameter D of the cylindrical section in each set of the cascade structure is the same, the number n of the cylindrical sections in each set of the cascade structure is different, and the height h of the cylindrical section in each set of the cascade structure is different. S2. Based on the formula v derived from the law of conservation of energy i =[2g(H-nδ j )] 1 / 2 Calculate the test height δ lost by the concrete as it passes through one section of the cylinder in each set of the simulation tests. j And the test height δ of multiple sets of the simulation tests j The average value is set as the single-section loss height δ; Where g is the acceleration due to gravity, H is the pouring height of the concrete, H=n×h+△h, and △h is the free fall height of the concrete from the lower end of the duct structure to the pouring surface; S3. Determine the quantity n and height h of the cylinders used at the construction site based on the construction conditions, and apply the formula v=[2g(H-nδ)]. 1 / 2 Calculate the falling velocity v of the concrete; Alternatively, the falling speed v and the number of cylinders n can be determined based on the construction conditions, and the formula v=[2g(H-nδ)] can be used. 1 / 2 Calculate the pouring drop height H Alternatively, the falling speed v and the pouring height H can be determined based on the construction conditions, and the formula v=[2g(H-nδ)] can be used. 1 / 2 Calculate the number n of the cylinders at the construction site.
2. The method for determining concrete drop parameters according to claim 1, characterized in that, In step S1, each group of simulation experiments is repeated multiple times to obtain multiple experimental speeds v. i .
3. The method for determining concrete drop parameters according to claim 2, characterized in that, Step S2 specifically includes the following steps: S21. Calculate the multiple test speeds v obtained from a set of simulation tests. i average velocity v k ; S22, the average velocity v k Substituting the number n of the cylinders in the corresponding group and the height h of the cylinders in the corresponding group into the formula v k =[2gn(h-δ j )] 1 / 2 In the middle, the test height δ of the corresponding group is calculated. j ; S23. Repeat steps S21 and S22 until multiple test heights δ are obtained. j ; S24. Calculate the multiple test heights δ j The average value is used to obtain the single-section loss height δ.
4. The method for determining concrete drop parameters according to claim 1, characterized in that, In step S3, the falling speed v is calculated; Step S3 is followed by the following steps: S4. Determine whether the falling speed v is greater than the limit speed; if yes, adjust the number n of the cylinders of the cascade structure, the height h of the cylinders of the cascade structure, and / or the slump of the concrete; if no, carry out the concrete pouring operation. The specified speed is the critical maximum speed at which the concrete does not segregate during its descent.
5. The method for determining concrete drop parameters according to claim 4, characterized in that, The specified speed is 3.0 m / s.
6. The method for determining concrete drop parameters according to claim 4, characterized in that, In step S4, if the falling speed v is greater than the limited speed, and the number of cylinders n, the height of the cylinder h, and the slump of the concrete are all fixed, a buffer device is installed at the lower cylinder opening of the cascade structure. The buffer device is used to buffer the concrete to reduce the falling speed v.
7. The method for determining concrete drop parameters according to any one of claims 1-6, characterized in that, In step S2, according to the law of conservation of energy, the gravitational potential energy mgH and the kinetic energy mv of the falling concrete are obtained. 2 The formula relating / 2 to the energy loss of concrete mgnδ is: mgH = mv 2 / 2+mgnδ; where m is the mass of the concrete; According to the formula mgH=mv 2 / 2+mgnδ derives v=[2g(H-nδ)] 1 / 2 .
8. The method for determining concrete drop parameters according to any one of claims 1-6, characterized in that, In step S1, when pouring concrete into the inner cavity of the cascade structure, the concrete is controlled to flow in a state where it does not completely fill the cross-section of the inner cavity of the cylinder.
9. The method for determining concrete drop parameters according to any one of claims 1-6, characterized in that, In step S1, the mix proportion of the concrete used in the simulation test is the same as that of the concrete used in actual construction, and the mix proportion of the concrete used in multiple sets of simulation tests is the same; the slump of the concrete used in the simulation test is the same as that of the concrete used in actual construction, and the slump of the concrete used in multiple sets of simulation tests is the same.
10. The method for determining concrete drop parameters according to any one of claims 1-6, characterized in that, In step S1, the connection methods for any two connected cylinders include lap joint connection and flange connection.