Method for determining concrete layer stacking parameters

Abstract

This invention belongs to the field of building construction technology and discloses a method for determining the layered packing parameters of concrete. The method includes the following steps: obtaining the first friction coefficient μ of the bottom structural surface, the apparent density ρ of the concrete, and the known packing parameters of the concrete layer based on the building construction plan; and determining the packing parameters based on τ... y =ρgh(sinα-μcosα) yields the uncalculated packing parameters of the concrete layer; known packing parameters include the preset yield stress τ of the concrete layer. y The method for determining the concrete layer stacking parameters includes any two of the preset layer thickness h and preset inclination angle α of the concrete layer. The stacking parameters to be calculated include the preset yield stress, preset layer thickness, and preset inclination angle, excluding the two known stacking parameters. This method not only establishes the relationship between yield stress, inclination angle, and thickness, but also fully considers the influence of friction between the concrete and the underlying structure.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a method for determining the parameters of concrete layer stacking. Background Technology

[0002] Large-volume concrete structures are characterized by their massive size and large volume of concrete poured in a single operation. The combined effects of concentrated heat release during hydration and the structure's own weight make them prone to problems such as temperature cracks, internal stress concentration, and instability due to rheological changes. Therefore, layered and segmented pouring techniques are commonly used in these projects to control construction risks. Before initial setting, concrete exhibits non-Newtonian fluid properties and will flow under gravity. Thus, during layered pouring, each layer will have a certain thickness and a vertically inclined shape.

[0003] In existing technologies, to ensure the final strength, durability, economy, and construction safety of concrete structures, concrete is required to maintain a stable packing morphology before initial setting. This stable packing morphology is primarily determined by the yield stress of the concrete itself. Only when the internal yield stress is sufficient to resist shear flow caused by gravity and construction disturbances can clear layer-by-layer interfaces and a regular structural shape be maintained. However, current research not only fails to consider the influence of friction between the concrete and the base slab on the stable packing morphology of the concrete, but also lacks a quantitative relationship between yield stress and the inclination angle and thickness of each pouring layer. This leads to quality problems such as poor interlayer bonding, excessive shape deviations, and early cracking during layered pouring construction, making it difficult to meet the requirements of construction controllability and long-term durability for large-volume concrete structures.

[0004] Therefore, there is an urgent need for a method to determine the parameters of concrete layer stacking 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 layer stacking parameters. This method not only establishes a quantitative relationship between yield stress and the inclination angle and thickness of concrete layers, but also fully considers the influence of friction between concrete and the bottom structure on the stable stacking morphology of concrete.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A method for determining concrete layer stacking parameters is provided, wherein concrete is poured in layers to the bottom structure;

[0008] The method for determining concrete layer stacking parameters includes the following steps:

[0009] S1. Based on the building construction plan, obtain the first friction coefficient μ of the bottom structural surface, the apparent density ρ of the concrete, and the known packing parameters of the concrete layer.

[0010] S2. Based on the relationship between concrete sliding shear force, sliding friction force, and yield stress, τ y =ρgh(sinα-μcosα) to obtain the uncalculated packing parameters of the concrete layer;

[0011] Where, τ y denoted as the preset yield stress of the concrete layer, g as the acceleration due to gravity, h as the preset thickness of the concrete layer, and α as the preset tilt angle of the concrete layer.

[0012] Known packing parameters include the preset yield stress τ y The preset layer thickness h and preset tilt angle α are any two of the following: the stacking parameters to be calculated include the preset yield stress τ. y The other one of the preset layer thickness h and preset tilt angle α, excluding the two included in the known stacking parameters.

[0013] Optionally, in step S1, the known stacking parameters obtained from the building construction plan include the preset yield stress τ. y and preset layer thickness h;

[0014] In step S2, the stacking parameters to be calculated according to the relational formula include the preset tilt angle α.

[0015] Optionally, in step S2, the preset tilt angle α is calculated iteratively according to the relational formula;

[0016] Step S2 specifically includes the following steps:

[0017] S211. Derive the iterative formula for the preset tilt angle α based on the relational formula;

[0018] The iterative formula is: α i+1 =arcsin(τ) y / ρgh+μcosα i );

[0019] Where i is the number of iterations, α i Let α be the preset tilt angle after i iterations. i+1 This is the preset tilt angle after iteration i+1;

[0020] S212. Based on the construction plan, define the initial α0 when it is iterated 0 times, and substitute α0 into the iteration formula to obtain α1 after iteration 1 time.

[0021] S213. Calculate the absolute value Δ1 of the difference between α0 and α1, and determine whether Δ1 is less than the preset value; if yes, stop the iterative calculation; if no, proceed to step S214.

[0022] S214. Calculate α corresponding to the current iteration i. iSubstituting into the iterative formula, we obtain α after iteration i+1. i+1 Subsequently, α is calculated. i With α i+1 The absolute value of the difference △ i+1 ;

[0023] S215, Determine △ i+1 Is it less than a preset value? If yes, stop the iterative calculation; if no, repeat step S214 until △ i+1 Less than the preset value;

[0024] S216, α in step S215 i+1 Set to the preset tilt angle α.

[0025] Optionally, step S2 specifically includes the following steps:

[0026] S221. According to the relational formula τ y =ρgh(sinα-μcosα) establishes the first friction coefficient μ and the preset yield stress τ. y A table showing the relationship between preset layer thickness h and preset tilt angle α;

[0027] S222. Based on the first friction coefficient μ and the known stacking parameters in step S1, consult the relationship table to obtain the preset tilt angle α.

[0028] Optionally, step S221 specifically includes the following steps:

[0029] S2211, Selecting multiple preset yield stresses τ y Given concrete, select multiple materials with known first friction coefficient μ as the bottom structure, and set the concrete layer to include multiple preset layer thicknesses h;

[0030] S2212, From the selected multiple preset yield stresses τ y Select a preset yield stress τ y Select one first friction coefficient μ from a plurality of selected first friction coefficients μ, select one preset layer thickness h from a plurality of set preset layer thicknesses h, and set the selected preset yield stress τ y Substituting the first friction coefficient μ and the preset layer thickness h into the relationship formula τ y In =ρgh(sinα-μcosα), the corresponding preset tilt angle α is calculated;

[0031] S2213. Repeat step S2212 until the multiple preset yield stresses τ are reached. y All combinations of multiple first friction coefficients μ and multiple preset layer thicknesses h are calculated to obtain multiple corresponding preset tilt angles α.

[0032] S2214, Based on multiple preset yield stresses τ y A relationship table is established for multiple first friction coefficients μ, multiple preset layer thicknesses h, and multiple preset tilt angles α.

[0033] Optionally, in step S1, the preset yield stress τ is obtained based on the building construction plan and the hydration dynamic model. y ;

[0034] The hydration dynamic model is: τ y (t)=τ y0 +k×t n ;

[0035] Where, τ y0 denoted as the initial yield stress of the concrete, t as the hydration time of the concrete, k as the hydration rate coefficient of the concrete, and n as the hydration time exponent of the concrete.

[0036] Optionally, in step S1, the concrete mix proportion and the temperature of the construction site are determined according to the building construction plan, and the hydration rate coefficient k and the hydration time index n are determined according to the concrete mix proportion and the temperature of the construction site.

[0037] Optionally, in step S1, the known stacking parameters obtained from the building construction plan include the preset layer thickness h and the preset tilt angle α;

[0038] In step S2, the stacking parameters to be calculated according to the relational formula include the preset yield stress τ. y ;

[0039] Step S2 is followed by the following steps: based on the preset yield stress τ y Determine the rationality of the concrete mix proportion.

[0040] Optionally, in step S1, the first friction coefficient μ is determined by a ramp test.

[0041] Optionally, the slope test uses a test platform, and the test tilt angle β of the test platform is adjustable;

[0042] The slope test includes the following steps:

[0043] P1. Lay the same test material as the bottom structure surface material on the surface of the test platform;

[0044] P2. Adjust the test tilt angle β of the test platform;

[0045] P3. Pour concrete from the highest point of the test platform onto the test platform;

[0046] P4. After the concrete stops flowing, measure the average thickness d of the concrete accumulated on the test platform.

[0047] P5. According to the relational formula τ y =ρgh(sinα-μcosα) calculate τ y =τ x The second coefficient of friction of the test material when h=d and α=β; where τ x The actual yield stress of the concrete used in the test;

[0048] P6. Change the test tilt angle β of the test platform and repeat steps P3 to P5m times.

[0049] P7. Calculate the average friction coefficient of m second friction coefficients, and set the average friction coefficient as the first friction coefficient μ of the bottom structure.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] This invention provides a method for determining concrete layer stacking parameters. Based on the gravity formula, the apparent density ρ of concrete, and the gravitational acceleration g, the gravity ρgh of a concrete layer with a preset layer thickness h and a cross-sectional area of ​​1 can be obtained. Through stress analysis of the concrete layer, the components of the concrete layer sliding downwards, ρghsinα, and the components of the concrete layer acting on the bottom structure along its thickness direction, ρghcosα, can be obtained. The component of the concrete layer sliding downwards is the sliding shear force of the concrete. Then, based on the gravity and sliding friction formula and the first friction coefficient μ, the sliding friction force μρghcosα between the concrete and the bottom structure can be obtained, and this sliding friction force is opposite in direction to the sliding shear force. In actual construction, to ensure the stable stacking shape of the concrete, it is necessary to control the resultant force ρgh(sinα-μcosα) of the concrete layer sliding downwards to be equal to the preset yield stress τ of the concrete layer. y Mutual balance, i.e., formula τ y =ρgh(sinα-μcosα), and thus this method for determining the concrete layer stacking parameters not only establishes a quantitative relationship between yield stress and the inclination angle and thickness of the concrete layer, but also fully considers the influence of friction between the concrete and the bottom structure on the stable stacking morphology of the concrete. This ensures that the pouring parameters obtained by this method can fully meet the needs of layered pouring construction, effectively avoid quality problems such as poor interlayer bonding, excessive shape deviation and early cracking, and improve the construction controllability and long-term durability of large-volume concrete structures. Attached Figure Description

[0052] Figure 1 A schematic diagram of the concrete layer to which the method for determining concrete layer stacking parameters provided by the present invention applies.

[0053] Figure 2 A stress analysis diagram of the concrete layer to which the method for determining concrete layer stacking parameters provided by this invention applies;

[0054] Figure 3 A first flowchart of step S2 in the method for determining concrete layer stacking parameters provided by the present invention;

[0055] Figure 4 A second flowchart of step S2 in the method for determining concrete layer stacking parameters provided by the present invention;

[0056] Figure 5 A schematic diagram of a slope test for the method of determining concrete layer stacking parameters provided by the present invention.

[0057] In the picture:

[0058] 10. Concrete layer;

[0059] 21. Test platform; 22. Support; 23. Adjustment component. Detailed Implementation

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] like Figures 1 to 5 As shown, this embodiment provides a method for determining concrete layer stacking parameters. It not only establishes a quantitative relationship between yield stress and the inclination angle and thickness of concrete layer 10, but also fully considers the influence of friction between concrete and the bottom structure on the stable stacking morphology of concrete.

[0065] See Figure 1 and Figure 2 The concrete is poured in layers up to the bottom structure; the method for determining the concrete layer stacking parameters includes the following steps:

[0066] S1. Based on the construction plan, obtain the first friction coefficient μ of the bottom structural surface, the apparent density ρ of the concrete, and the known packing parameters of the concrete layer 10.

[0067] S2. Based on the relationship between concrete sliding shear force, sliding friction force, and yield stress, τ y =ρgh(sinα-μcosα) to obtain the uncalculated stacking parameters of concrete layer 10;

[0068] Where, τ y denoted as the preset yield stress of concrete layer 10, g is the gravitational acceleration, h is the preset layer thickness of concrete layer 10, and α is the preset tilt angle of concrete layer 10.

[0069] Known packing parameters include the preset yield stress τ y The preset layer thickness h and preset tilt angle α are any two of the following: the stacking parameters to be calculated include the preset yield stress τ. y The other one of the preset layer thickness h and preset tilt angle α, excluding the two included in the known stacking parameters.

[0070] The method for determining concrete layer stacking parameters provided in this embodiment, based on the gravity formula, the apparent density ρ of concrete, and the gravitational acceleration g, can obtain the gravity ρgh of concrete layer 10 when the layer thickness is a preset layer thickness h and the cross-sectional area is 1. Through force analysis of concrete layer 10, the component force ρghsinα of the downward sliding of concrete layer 10 and the component force ρghcosα of concrete layer 10 acting on the bottom structure along its thickness direction can be obtained. The component force of the downward sliding of concrete layer 10 is the sliding shear force of the concrete. Then, based on the gravity and sliding friction formula and the first friction coefficient μ, the sliding friction force μρghcosα between the concrete and the bottom structure can be obtained, and this sliding friction force is opposite in direction to the sliding shear force. In actual construction, to ensure the stable stacking shape of the concrete, it is necessary to control the resultant force ρgh(sinα-μcosα) of the downward sliding of concrete layer 10 to be equal to the preset yield stress τ of concrete layer 10. y Mutual balance, i.e., formula τ y =ρgh(sinα-μcosα), and thus this method for determining the concrete layer stacking parameters not only establishes a quantitative relationship between the yield stress and the inclination angle and thickness of the concrete layer 10, but also fully considers the influence of the friction between the concrete and the bottom structure on the stable stacking shape of the concrete. This ensures that the pouring parameters obtained by this method can fully meet the needs of layered pouring construction, effectively avoid the occurrence of quality problems such as poor interlayer bonding, excessive shape deviation and early cracks, and improve the construction controllability and long-term durability of large-volume concrete structures.

[0071] Specifically, in step S1, the type of concrete used in the construction can be determined according to the building construction plan. Once the type of concrete is determined, the apparent density ρ of the concrete can be obtained.

[0072] For example, the apparent density of ordinary concrete is 1950 kg / m³. 3 ~2800kg / m 3 Between these two values, the apparent density of heavy concrete shall not be less than 2800 kg / m³. 3 The apparent density of lightweight concrete is less than 1950 kg / m³. 3 .

[0073] In an optional embodiment, in step S1, the known stacking parameters obtained from the building construction plan include the preset yield stress τ. y And the preset layer thickness h; in step S2, the stacking parameters to be calculated according to the relational formula include the preset tilt angle α. In some projects, the preset yield stress τ of concrete is... yThe preset layer thickness h of the concrete layer 10 to be poured has been determined. At this time, the preset tilt angle α can be quickly obtained according to the relationship formula, so that the workers can accurately control the pouring angle of the concrete according to the preset tilt angle α during actual pouring, effectively improving the stability of the accumulation shape of the concrete after pouring.

[0074] In some embodiments, in step S1, the thickness of the concrete layer 10 to be poured can be determined according to the building construction plan, that is, the preset layer thickness h, and then in step S2, the preset layer thickness h can be directly substituted into the relational formula.

[0075] In some embodiments, in step S1, the preset yield stress τ of the concrete used for construction can be determined according to the construction plan. y If the concrete used is relatively common, its preset yield stress τ is... y The pre-set yield stress τ can be obtained directly by consulting literature; if the concrete used is relatively rare, the pre-set yield stress τ can be determined according to the following method. y .

[0076] Specifically, in step S1, the preset yield stress τ is obtained based on the building construction plan and the hydration dynamic model. y ;

[0077] The hydration dynamic model is: τ y (t)=τ y0 +k×t n ;

[0078] Where, τ y0 denoted as the initial yield stress of the concrete, t as the hydration time of the concrete, k as the hydration rate coefficient of the concrete, and n as the hydration time exponent of the concrete.

[0079] During concrete pouring, the hydration reaction affects the yield stress of the concrete; that is, the yield stress before and after hydration will differ. In this embodiment, the preset yield stress τ is obtained based on the hydration dynamic model. y The influence of hydration reaction is fully considered, which significantly improves the accuracy and reliability of the calculation results of the stacking parameters to be calculated.

[0080] For example, the initial yield stress τ of the concrete when it leaves the batching plant can be obtained based on the concrete mix proportions. y0 This process is existing technology and will not be described in detail here.

[0081] For example, in step S1, the concrete mix proportion and the temperature of the construction site are determined according to the building construction plan, and the hydration rate coefficient k and hydration time exponent n are determined according to the concrete mix proportion and the temperature of the construction site, so as to preset the yield stress τ for the subsequent process. y The calculations provide data support.

[0082] The hydration kinetic model is a mathematical model describing the rate, degree of hydration, heat release, and strength development of the chemical reaction between cement and water. Its core is the quantitative relationship between the degree of hydration and time, temperature, and material composition. The hydration kinetic model used in this embodiment is an empirical formula obtained by converting the degree of hydration into yield stress and coupling it through a power function; this is existing technology in the field. Furthermore, the process of determining the hydration rate coefficient k and the hydration time exponent n based on the mix proportion and ambient temperature is also existing technology in the field and will not be elaborated here.

[0083] In this embodiment, in step S2, the preset tilt angle α is calculated iteratively according to the relational formula.

[0084] According to the relational formula τ y =ρgh(sinα-μcosα) can be derived to obtain α=arcsin(τ) y / ρgh+μcosα), since there are unknown parameters and a preset tilt angle α on both sides of the equation, the preset tilt angle α can be calculated iteratively.

[0085] Specifically, see Figure 3 Step S2 specifically includes the following steps:

[0086] S211. Derive the iterative formula for the preset tilt angle α based on the relational formula;

[0087] The iterative formula is: α i+1 =arcsin(τ) y / ρgh+μcosα i );

[0088] Where i is the number of iterations, α i Let α be the preset tilt angle after i iterations. i+1 This is the preset tilt angle after iteration i+1;

[0089] S212. Based on the construction plan, define the initial α0 when it is iterated 0 times, and substitute α0 into the iteration formula to obtain α1 after iteration 1 time.

[0090] S213. Calculate the absolute value Δ1 of the difference between α0 and α1, and determine whether Δ1 is less than the preset value; if yes, stop the iterative calculation; if no, proceed to step S214.

[0091] S214. Calculate α corresponding to the current iteration i. i Substituting into the iterative formula, we obtain α after iteration i+1. i+1 Subsequently, α is calculated. i With α i+1 The absolute value of the difference △ i+1 ;

[0092] S215, Determine △ i+1 Is it less than a preset value? If yes, stop the iterative calculation; if no, repeat step S214 until △ i+1 Less than the preset value.

[0093] Among them, when △ i+1 When it is less than the preset value, α i =α i+1 .

[0094] S216, α in step S215 i+1 Set to the preset tilt angle α.

[0095] The preset value is used to determine △ i+1 Whether convergence is determined by setting an infinitesimally small value, and the method for determining convergence is existing technology in this field, which will not be elaborated here.

[0096] In other embodiments, step S2 specifically includes the following steps:

[0097] S221. According to the relational formula τ y =ρgh(sinα-μcosα) establishes the first friction coefficient μ and the preset yield stress τ. y A table showing the relationship between the preset layer thickness h and the preset tilt angle α.

[0098] Specifically, step S221 includes the following steps:

[0099] S2211, Selecting multiple preset yield stresses τ y The known concrete is selected from a variety of materials with a known first friction coefficient μ as the bottom structure, and the concrete layer 10 includes a variety of preset layer thicknesses h;

[0100] S2212, From the selected multiple preset yield stresses τ y Select a preset yield stress τ y Select one first friction coefficient μ from a plurality of selected first friction coefficients μ, select one preset layer thickness h from a plurality of set preset layer thicknesses h, and set the selected preset yield stress τ y Substituting the first friction coefficient μ and the preset layer thickness h into the relationship formula τ y In =ρgh(sinα-μcosα), the corresponding preset tilt angle α is calculated;

[0101] S2213. Repeat step S2212 until the multiple preset yield stresses τ are reached. y All combinations of multiple first friction coefficients μ and multiple preset layer thicknesses h are calculated to obtain multiple corresponding preset tilt angles α.

[0102] S2214, Based on multiple preset yield stresses τ y A relationship table is established for multiple first friction coefficients μ, multiple preset layer thicknesses h, and multiple preset tilt angles α.

[0103] For example, N1 representative types of concrete are selected, and the preset yield stress τ of these concretes is... y All of these are existing technologies in the field, which can be directly obtained, and the preset yield stress τ of these concretes... y Set sequentially to τ y1 τ y2 τ y3 …τ yN1 N2 representative materials were selected as the bottom structure. The first coefficient of friction μ of these materials is existing technology in this field and can be directly obtained. The first coefficient of friction μ of these materials was set sequentially as μ1, μ2, μ3...μ N2 Based on on-site construction experience, there are N3 possible thicknesses for the concrete layer on the construction site, which are designated as h1, h2, h3…h N3 Furthermore, based on the relational formula τ y When calculating =ρgh(sinα-μcosα), N1 preset yield stresses τ y The N2 first friction coefficients μ and N3 preset layer thicknesses h can be combined in various ways, such as (τ y1 、μ1、h1)(τ y1 (μ2, h3), (τ) y2 Each combination of μ1, h3, etc., calculates a preset tilt angle α.

[0104] The relationship tables established after step S221 are shown in Tables 1 and 2 below. Tables 1 and 2 are only used to illustrate the preset yield stress τ. y The correspondence between the first friction coefficient μ, the preset layer thickness h, and the preset tilt angle α does not constitute any specific numerical limitation.

[0105]

[0106] Table 1

[0107]

[0108] Table 2

[0109] S222. Based on the first friction coefficient μ and the known stacking parameters in step S1, consult the relationship table to obtain the preset tilt angle α.

[0110] Referring to Tables 1 and 2, when the first friction coefficient μ and the preset yield stress τy Once the preset layer thickness h is known, the corresponding preset tilt angle α can be obtained by looking up the table.

[0111] In another alternative embodiment, see [link to relevant documentation]. Figure 4 In step S1, the known stacking parameters obtained from the building construction plan include the preset layer thickness h and the preset inclination angle α; in step S2, the stacking parameters to be calculated according to the relational formula include the preset yield stress τ. y In some projects, the predetermined inclination angle α and the predetermined thickness h of the concrete layer 10 have been determined. In this case, the predetermined yield stress τ can be obtained according to the relevant formula. y This allows workers to determine the optimal yield stress τ during actual construction. y Precisely adjusting the concrete mix ratio effectively improves the stability of the concrete's accumulated shape after pouring.

[0112] In this embodiment, after step S2, the following step is also included: according to the preset yield stress τ y To determine the rationality of the concrete mix design, it is necessary to ascertain whether the current mix design can guarantee the stability of the concrete's stacking shape after pouring.

[0113] Specifically, the type of concrete used in the current project can be determined based on the construction plan, and then the preset yield stress τ of the concrete can be determined based on existing technology in this field. y Recommended range; subsequently, determine the preset yield stress τ obtained from step S2. y If the concrete mix design falls within the recommended range, then the concrete mix proportion meets the requirements; otherwise, it needs to be adjusted. This judgment and adjustment process is existing technology in this field and will not be elaborated here.

[0114] In an alternative embodiment, when the bottom structure is made of some common materials, its first coefficient of friction μ can be obtained by consulting existing literature, which is convenient and quick.

[0115] In another alternative embodiment, when the first friction coefficient μ cannot be obtained by consulting literature, it can be quickly determined in a laboratory or construction site through micro-experiments to provide reliable data support for subsequent calculations.

[0116] Specifically, in step S1, the first friction coefficient μ is determined through a slope test.

[0117] See Figure 5 The slope test uses test platform 21, and the test tilt angle β of test platform 21 is adjustable.

[0118] Specifically, see Figure 5One end of the test platform 21 is provided with a support 22 hinged to it, and the other end of the test platform 21 is provided with an adjustable member 23, such as a telescopic rod. When the length of the adjustable member 23 is equal to the length of the support 22, the test platform 21 is in a horizontal state, β=0; when the length of the adjustable member 23 is greater than or equal to the length of the support 22, the test platform 21 is vertically tilted, β>0; and the greater the difference between the length of the adjustable member 23 and the length of the support 22, the greater the test tilt angle β; the smaller the difference between the length of the adjustable member 23 and the length of the support 22, the smaller the test tilt angle β.

[0119] In this embodiment, the slope test includes the following steps:

[0120] P1. Lay the same test material as the bottom structure surface material on the surface of the test platform 21 so that the test platform 21 can truly simulate the bottom structure.

[0121] P2. Adjust the test tilt angle β of the test platform 21.

[0122] P3. Pour concrete from the highest point of test platform 21 onto test platform 21 to realistically simulate the concrete pouring situation during construction.

[0123] The mix proportions of the concrete used in the experiment were the same as those used in the actual construction.

[0124] When pouring concrete, the pouring position should be controlled to be close to the highest point of the test platform 21 in order to reduce the impact of kinetic energy on the flow of concrete during pouring.

[0125] P4. After the concrete stops flowing, measure the average thickness d of the concrete accumulated on the test platform 21.

[0126] Specifically, after the concrete stops flowing, multiple measurement points are selected along the inclined direction of the test platform 21, and the thickness of the concrete accumulation at each measurement point is measured one by one using measuring tools; after the thickness at multiple measurement points is measured, the average value of the measured thicknesses is calculated to obtain the average thickness d.

[0127] P5. According to the relational formula τ y =ρgh(sinα-μcosα) calculate τ y =τ x The second coefficient of friction of the test material when h=d and α=β; where τ x The actual yield stress of the concrete used in the test is given.

[0128] Once the concrete mix proportions are determined, the actual yield stress τ of the concrete... x Since these are known parameters, they can be directly substituted into the relational formula for calculation.

[0129] P6. Change the test tilt angle β of the test platform 21 and repeat steps P3 to P5m times.

[0130] P7. Calculate the average friction coefficient of m second friction coefficients, and set the average friction coefficient as the first friction coefficient μ of the bottom structure.

[0131] For example, when m=1, the process of obtaining the first friction coefficient μ is as follows:

[0132] In step P2, the test tilt angle β of the test platform 21 is adjusted to β1; in step P4, the calculated average thickness d is d1; in step P5, according to the relationship formula τ y =ρgh(sinα-μcosα)to obtain τ x =ρgd1(sinβ1-μcosβ1).

[0133] In step P6, the test tilt angle β of the test platform 21 is adjusted to β2, and the calculated average thickness d is d2. According to the relationship formula τ... y =ρgh(sinα-μcosα)to obtain τ x =ρgd2(sinβ2-μcosβ2).

[0134] In step P7, according to τ x =ρgd1(sinβ1-μcosβ1)=ρgd2(sinβ2-μcosβ2) can be deduced to μ=(d1sinβ1-d2sinβ2) / (d1cosβ1-d2cosβ2).

[0135] In some embodiments, after multiple slope tests, a certain number of first friction coefficients μ of the bottom structure can be obtained. At this time, a lookup table of the first friction coefficients μ can be established based on existing data and test structures, as shown in Table 3 below. This allows workers to directly select the required first friction coefficients μ from the lookup table during subsequent construction, making the operation convenient and quick.

[0136]

[0137] Table 3

[0138] Table 3 is only used to illustrate the correspondence between the bottom structure material type, bottom structure surface condition, the value of the first friction coefficient μ and its acquisition method, and does not constitute any specific numerical limitation.

[0139] 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 layer stacking parameters, characterized in that, Concrete is poured in layers up to the bottom structure; The method for determining the concrete layer stacking parameters includes the following steps: S1. Based on the construction plan, obtain the first friction coefficient μ of the bottom structure surface, the apparent density ρ of the concrete, and the known packing parameters of the concrete layer (10). S2, obtaining the to-be-calculated accumulation parameters of the concrete layer (10) according to the relationship formula τ = ρgh (sin α - μcos α) between the concrete sliding shear force, the sliding friction force and the yield stress y = ρgh (sin α - μcos α) Where, τ y α is the preset yield stress of the concrete layer (10), g is the gravitational acceleration, h is the preset layer thickness of the concrete layer (10), and α is the preset tilt angle of the concrete layer (10). The known packing parameters include the preset yield stress τ. y The preset layer thickness h and the preset tilt angle α are either two of the following, and the stacking parameters to be calculated include the preset yield stress τ. y The other one of the preset layer thickness h and the preset tilt angle α, besides the two included in the known stacking parameters; In step S1, the known stacking parameters obtained according to the construction plan include the preset yield stress τ. y And the preset layer thickness h; in step S2, when the stacking parameters to be calculated according to the relationship formula include the preset tilt angle α; In step S1, the preset yield stress τ is obtained based on the building construction plan and the hydration dynamic model. y ; The hydration dynamics model is: τ y (t)=τ y0 +k×t n ; Where, τ y0 denoted as the initial yield stress of the concrete, t as the hydration time of the concrete, k as the hydration rate coefficient of the concrete, and n as the hydration time exponent of the concrete. In step S1, the concrete mix proportion and the temperature of the construction site are determined according to the building construction plan, and the hydration rate coefficient k and the hydration time index n are determined according to the concrete mix proportion and the temperature of the construction site.

2. The method for determining concrete layer stacking parameters according to claim 1, characterized in that, In step S1, the known packing parameters obtained from the building construction plan include the preset yield stress τ. y and the preset layer thickness h; In step S2, the stacking parameters to be calculated according to the relationship formula include the preset tilt angle α; In step S2, the preset tilt angle α is calculated iteratively according to the relationship formula; Step S2 specifically includes the following steps: S211. Derive the iterative formula for the preset tilt angle α based on the aforementioned relational formula; The iterative formula is: α i+1 =arcsin(τ) y / ρgh+μcosα i ); Where i is the number of iterations, α i α is the preset tilt angle after i iterations. i+1 The preset tilt angle is the result of iteration i+1. S212. Based on the building construction plan, define the initial α0 when iterating 0 times, and substitute α0 into the iterative formula to obtain α1 after iterating 1 time. S213. Calculate the absolute value Δ1 of the difference between α0 and α1, and determine whether Δ1 is less than the preset value; if yes, stop the iterative calculation; if no, proceed to step S214. S214. Calculate the α corresponding to the current iteration after i iterations. i Substituting into the iterative formula, we obtain α after iteration i+1. i+1 Subsequently, α is calculated. i With α i+1 The absolute value of the difference △ i+1 ; S215, Determine △ i+1 Is it less than the preset value? If yes, stop the iterative calculation; if no, repeat step S214 until △ i+1 Less than the preset value; S216, α in step S215 i+1 The preset tilt angle α is set.

3. The method for determining concrete layer stacking parameters according to claim 2, characterized in that, Step S2 specifically includes the following steps: S221. According to the aforementioned relational formula τ y =ρgh(sinα-μcosα) establishes the first friction coefficient μ and the preset yield stress τ. y A table showing the relationship between the preset layer thickness h and the preset tilt angle α; S222. Based on the first friction coefficient μ and the known stacking parameters in step S1, consult the relationship table to obtain the preset tilt angle α.

4. The method for determining concrete layer stacking parameters according to claim 3, characterized in that, Step S221 specifically includes the following steps: S2211, Selecting multiple preset yield stresses τ y Given concrete, select a variety of materials with known first friction coefficient μ as the bottom structure, and set the concrete layer (10) to include a variety of preset layer thicknesses h; S2212, From the selected plurality of said preset yield stresses τ y Select one of the preset yield stresses τ y Select one first friction coefficient μ from a plurality of selected first friction coefficients μ, select one preset layer thickness h from a plurality of set preset layer thicknesses h, and set the selected preset yield stress τ y Substituting the first friction coefficient μ and the preset layer thickness h into the relationship formula τ y In =ρgh(sinα-μcosα), the corresponding preset tilt angle α is calculated; S2213. Repeat step S2212 until the multiple preset yield stresses τ are reached. y All combinations of the multiple first friction coefficients μ and the multiple preset layer thicknesses h are calculated to obtain multiple corresponding preset tilt angles α; S2214, according to the multiple preset yield stresses τ y The relationship table is established by multiple first friction coefficients μ, multiple preset layer thicknesses h, and multiple preset tilt angles α.

5. The method for determining concrete layer stacking parameters according to claim 1, characterized in that, In step S1, the known stacking parameters obtained from the building construction plan include the preset layer thickness h and the preset tilt angle α; In step S2, the stacking parameters to be calculated according to the relationship formula include the preset yield stress τ. y ; Step S2 is followed by the following steps: according to the preset yield stress τ y Determine the rationality of the concrete mix proportion.

6. The method for determining concrete layer stacking parameters according to claim 1, characterized in that, In step S1, the first friction coefficient μ is determined by a slope test.

7. The method for determining concrete layer stacking parameters according to claim 6, characterized in that, The slope test uses a test platform (21), and the test tilt angle β of the test platform (21) is adjustable; The slope test includes the following steps: P1. Lay the same test material as the bottom structure surface material on the surface of the test platform (21); P2. Adjust the test tilt angle β of the test platform (21); P3. Pour concrete from the highest point of the test platform (21) onto the test platform (21). P4. After the concrete stops flowing, measure the average thickness d of the concrete accumulated on the test platform (21). P5. According to the relationship formula τ y =ρgh(sinα-μcosα) calculate τ y =τ x The second coefficient of friction of the test material when h=d and α=β; where τ x The actual yield stress of the concrete used in the test; P6. Change the test tilt angle β of the test platform (21) and repeat steps P3 to P5m times. P7. Calculate the average friction coefficient of m second friction coefficients, and set the average friction coefficient as the first friction coefficient μ of the bottom structure.

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