A parameter determination method and determination system for preventing high-speed concrete from segregation

Abstract

The invention discloses a parameter determination method for preventing high-speed concrete from segregation, comprising inputting slurry density, aggregate density, average density, aggregate particle size, particle ball equivalent diameter, volume concentration, slurry viscosity, and chute inner diameter in concrete, establishing a calculation relationship between relative speed, slurry chute speed, and aggregate chute speed, inputting a relative speed corresponding to a segregation judgment standard, solving the relationship, inputting the chute speed, and judging the size, if yes, outputting that the concrete chute speed will not segregate; if no, outputting that the concrete chute speed will segregate, and re-judging after correcting the chute speed; the invention can effectively avoid the phenomenon of segregation by inputting relevant parameters of concrete including but not limited to aggregate density, slurry density, concrete density, aggregate particle size, volume concentration, chute inner diameter, and obtaining an optimal chute speed by calculation.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering, and in particular to a parameter determination method and a determination system for preventing high-speed concrete from segregating. Background Art

[0002] Due to the narrow valley, a large number of hydropower station power plants are underground. With the increase of installed capacity, the scale of underground cavern groups is getting larger and larger, with large cross-sections, high depths, large diameters and complex structures as their prominent features. The transportation and pouring of large volumes of concrete is one of the most important links.

[0003] The vertical pipeline chute method arranges ordinary steel pipes as chutes from the top of the shaft to transport concrete from the ground to the structural parts.

[0004] At present, there are two states of concrete flow: non-full pipe flow and full pipe flow. In the non-full pipe flow, there is a speed difference between the coarse aggregate and the slurry, which usually causes flow segregation. In the full pipe flow, there is generally no segregation because the concrete flows as a plunger in the pipe.

[0005] The reasons for vertical chute segregation include:

[0006] The coarse aggregate rolls in the tube, collides and jumps with the tube wall in a zigzag line. The total route is long and the collision consumes energy. In addition, the coarse aggregate collides and squeezes each other, resulting in a speed difference with the slurry, and finally the aggregate lags behind the slurry and separates first.

[0007] During the vertical sliding process, the mortar attached to the wall of the pipe rubs against the entire wall of the pipe during the falling process, and the sliding speed drops significantly. The aggregates are mostly cushioned on the slurry layer and fall faster than the slurry. As a result, over a longer sliding distance, segregation occurs in which the slurry lags behind due to friction with the wall and the aggregates fall first.

[0008] However, there is a lack of specific calculation methods at this stage, and we can only rely on experience to prevent segregation. Summary of the invention

[0009] The technical problem to be solved by the present invention is that at present, the conveying parameters can only be controlled by manual experience to avoid segregation. The purpose is to provide a parameter determination method and determination system for preventing segregation of high-speed conveying concrete, thereby solving the segregation problem that may occur during vertical conveying.

[0010] The present invention is achieved through the following technical solutions:

[0011] A method for determining parameters for preventing high-speed concrete from segregating comprises:

[0012] Input the density of the slurry in the concrete ρ l , aggregate density ρ sand the average density of concrete, ρ;

[0013] Input the aggregate particle size d and the equivalent diameter of the particle ball d in the concrete e ;

[0014] Enter the volume concentration C of aggregate with diameter d in the total concrete v ;

[0015] Input concrete slurry viscosity μ;

[0016] The inner diameter D of the input slide pipe;

[0017] Let the slurry flow velocity along the inner wall of the slide pipe be v l The aggregate's velocity in the falling process of the chute is v s ;

[0018] Establish the relative velocity v between the slurry and aggregate phases t , slurry conveying speed v l and aggregate conveying speed v s The calculation relationship between:

[0019] Where α, β, and n are Swanson shape coefficients;

[0020] Input the relative speed v corresponding to the separation judgment standard t , and solve the relationship to obtain v l and v s ;

[0021] Enter the concrete conveying speed v in the chute m , and determine v m <(v s +v l ) / 2If yes, then the output of the concrete delivery speed will not be segregated; if no, then the output of the concrete delivery speed will be segregated, and the judgment will be made again after the delivery speed is corrected.

[0022] Specifically, the relative velocity v between the slurry and aggregate phases is t , slurry conveying speed v l and aggregate conveying speed v s The methods for establishing the relationship between include:

[0023] Calculate the Reynolds number for concrete:

[0024] Calculate the drag coefficient of slurry on aggregate:

[0025] Calculate the viscous drag force of slurry on aggregate:

[0026] Calculate the buoyancy of the slurry on the aggregate: Where g is the acceleration due to gravity;

[0027] Calculate the effective weight w of aggregate particles s :

[0028] Calculate the interference force between aggregates:

[0029] Establish the force balance equation of bone particles: G = f d +f b +Kf h ;

[0030] Obtain the relative velocity v between the slurry and aggregate phases t , slurry conveying speed v l and aggregate conveying speed v s The relationship between:

[0031]

[0032] Specifically, the calculation method of the Swanson shape coefficient includes:

[0033] Calculate the aggregate area index: Where b and l are the axial diameters of the two axes of the aggregate particle space except the longest axis;

[0034] Calculate the Swanson shape coefficient α,

[0035] Calculate the Swanson shape coefficient β,

[0036] Calculate the Swanson shape factor n,

[0037] Preferably, α=0.6626 and β=5.368.

[0038] Furthermore, multiple conveying speeds of aggregates of all particle sizes in the concrete are output in sequence, and the minimum value of the multiple conveying speeds is taken and output as the final conveying speed.

[0039] As a further optimization, calculate the negative air pressure Where ρk is the compressed density of the air section between the two concrete sections in the chute;

[0040] Create the balanced equation:

[0041] Where v0 is the initial velocity of the concrete, and t is the speed at which the concrete accelerates from v0 to v m time;

[0042] Establish the equation of motion:

[0043] Calculate the maximum length of the slide pipe:

[0044] Preferably, t≈2s, v0=0.

[0045] A parameter determination system for preventing high-speed concrete from segregating, comprising:

[0046] The first input module is used to input the density of the slurry in the concrete l , aggregate density ρ s And the average density of concrete ρ, the slurry viscosity of concrete μ, the inner diameter D of the chute;

[0047] The second input module is used to input the aggregate particle size d and the equivalent diameter d of the particle ball in the concrete. e The volume concentration of aggregate with diameter d in the total concrete is C v ;

[0048] The parameter establishment module is used to set the slurry velocity v during the process of falling along the inner wall of the slide pipe. l The aggregate's velocity in the falling process of the chute is v s ;

[0049] Calculation module for establishing the relative velocity v between the slurry and aggregate phases t , slurry conveying speed v l and aggregate conveying speed v s The calculation relationship between:

[0050] Where α, β, and n are Swanson shape coefficients;

[0051] The third input module is used to input the relative speed v corresponding to the separation judgment standard t , and solve the relationship to obtain v l and v s ;

[0052] The fourth input module is used to input the concrete conveying speed v in the chute. m ;

[0053] The judgment module is used to judge v m <(v s +v l ) / 2;

[0054] The output module is used to output that the concrete delivery speed will not be segregated when the determination module determines that it is yes; when the determination module determines that it is no, output that the concrete delivery speed will be segregated, and re-determine after correcting the delivery speed.

[0055] Specifically, the calculation module includes:

[0056] The first calculation module is used to calculate the Reynolds number of concrete:

[0057] The second calculation module is used to calculate the drag coefficient of the slurry on the aggregate:

[0058] The third calculation module is used to calculate the viscous drag force of the slurry on the aggregate:

[0059] The fourth calculation module is used to calculate the buoyancy of the slurry on the aggregate: Where g is the acceleration due to gravity;

[0060] The fifth calculation module is used to calculate the effective gravity w of aggregate particles s :

[0061] The sixth calculation module is used to calculate the interference force between aggregates:

[0062] Modeling module, used to establish the force balance equation of bone particles: G = f d +f b +Kf h ;

[0063] The seventh calculation module is used to obtain the relative velocity v between the slurry and aggregate phases t , slurry conveying speed v l and aggregate conveying speed v s The relationship between:

[0064]

[0065] Preferably, the aggregate particle size, particle ball equivalent diameter, and volume concentration of the aggregate in the total concrete of different aggregates in the concrete are input into the second input module, and a plurality of different conveying speeds are output through the parameter establishment module, the calculation module, the third input module, the fourth input module, the determination module, and the output module;

[0066] The parameter determination system also includes:

[0067] The comparison module is used to obtain the minimum value of multiple different sliding speeds and output it as the final sliding speed.

[0068] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0069] The present invention can effectively avoid the phenomenon of segregation by inputting relevant parameters of concrete including but not limited to aggregate density, slurry density, concrete density, aggregate particle size, volume concentration, inner diameter of chute, etc., and obtaining the optimal chute speed by calculation.

[0070] After determining the conveying speed, the length of the slide pipe can be calculated based on the conveying speed to avoid segregation of the transition surface under the action of air pressure when an air segment appears. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and the accompanying drawings are included in and constitute a part of this specification and do not constitute a limitation of the embodiments of the present invention.

[0072] Figure 1 It is a flow chart of a parameter determination method for preventing segregation of high-speed concrete according to the present invention.

[0073] Figure 2 It is a flowchart of the second embodiment according to the present invention.

[0074] Figure 3 It is a flowchart of the third embodiment according to the present invention. DETAILED DESCRIPTION

[0075] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation methods. It is understood that the specific implementation methods described herein are only used to explain the relevant content, rather than to limit the present invention.

[0076] It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the drawings.

[0077] In the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. Figure 1 , Figure 2 and Figure 3 The present invention is described in detail in conjunction with the embodiments.

[0078] There are two states of concrete flow: non-full pipe flow and full pipe flow. In non-full pipe flow, there is a speed difference between coarse aggregate and slurry, which usually leads to flow segregation. In full pipe flow, there is generally no segregation because the concrete flows as a plunger in the pipe.

[0079] Therefore, the flow separation analysis is first carried out on the free flow of the non-full pipe.

[0080] Vertical flow segregation is different from horizontal / near-horizontal flow segregation. The process is complex and involves many factors. Its segregation mechanism is:

[0081] (1) The repeated drops and impacts during the conveying process caused the mortar to liquefy, and the water in the mortar seeped out under the repeated impact force.

[0082] (2) The coarse aggregate rolls in the tube, collides and jumps with the tube wall in a zigzag line. The total route is long and the collision consumes energy. In addition, the coarse aggregate collides and squeezes each other, resulting in a speed difference with the slurry. Finally, the aggregate lags behind the slurry and separates first.

[0083] (3) During the vertical conveying process, the mortar attached to the pipe wall rubs against the entire pipe wall during the falling process, and the conveying speed drops significantly. The aggregate is mostly cushioned on the slurry layer and falls faster than the slurry. As a result, at a longer conveying distance, the slurry lags behind due to friction with the wall, while the aggregate falls first.

[0084] Processes (2) and (3) influence each other. According to current engineering experience, the premature falling of aggregate stone is the main form of segregation.

[0085] Regarding the measurement and evaluation of segregation, it is currently generally determined by on-site observation with the human eye or by coring of concrete stones afterwards. Human factors and engineering quality monitoring that lags behind the construction progress are too significant.

[0086] Therefore, in this embodiment, the concept of relative speed between coarse aggregate and slurry is used to carry out segregation judgment. For the convenience of derivation, it is assumed that:

[0087] (1) Concrete consists of two phases: aggregate and paste. The air phase is not considered. The fluidity of the paste conforms to the characteristics of Bingham fluid, and the viscosity coefficient is a constant during transportation.

[0088] (2) There is no vibration or heat exchange during the conveying process, and the collision between the aggregate and the pipe wall is ignored.

[0089] (3) The slurry completely wraps around the aggregate, that is, the aggregate is filled with the slurry and suspended in the slurry.

[0090] Embodiment 1

[0091] like Figure 1 As shown, based on the above assumptions, this embodiment provides a method for determining parameters for preventing segregation of high-speed concrete, including:

[0092] The first step is to input the density of the slurry in the concrete: l , aggregate density ρ sAnd the average density of concrete ρ; input the slurry viscosity μ of the concrete; input the inner diameter D of the chute.

[0093] In this step, the concrete that needs to be transported is customized, so it only needs to be determined once.

[0094] The second step is to input the aggregate particle size d and particle ball equivalent diameter d in the concrete. e ;

[0095] Enter the volume concentration C of aggregate with diameter d in the total concrete v

[0096] In practice, the aggregates in concrete include large aggregates, small aggregates and other aggregates of various sizes. Therefore, in order to measure aggregates of various sizes specifically, it is necessary to repeatedly input relevant parameters.

[0097] The third step is that from the above content, we know that the segregation phenomenon occurs because the slurry flow rate is lower than the aggregate flow rate. Therefore, in order to determine it, we assume that the slurry flow rate along the inner wall of the chute is v. l The aggregate's velocity in the falling process of the chute is v s ;

[0098] The fourth step is to establish the relative velocity v between the slurry and aggregate phases. t , slurry conveying speed v l and aggregate conveying speed v s The calculation relationship between:

[0099] Among them, α, β, and n are Swanson shape coefficients. The Swanson shape coefficients can take constant values ​​or be calculated according to specific conditions.

[0100] Step 5: Input the relative speed v corresponding to the separation judgment standard t , and solve the relationship to obtain v l and v s , determine the separation judgment standard, in this embodiment, it can be set when v t When the speed is greater than 0.01m / s, segregation will occur, and the value can be taken as 0.01 for solution and calculation.

[0101] Step 6: Input the concrete conveying speed v in the chute m , and determine v m <(v s +v l ) / 2, that is, input the required speed of concrete delivery and determine its size.

[0102] If yes, then the output concrete delivery speed will not be segregated, and the corresponding concrete can be delivered at this speed.

[0103] If not, the output of the concrete feeding speed will result in segregation, and re-judgment will be made after the feeding speed is corrected, which proves that the feeding speed is too fast and segregation will occur, and the set feeding speed needs to be reduced.

[0104] Embodiment 2

[0105] like Figure 2 As shown, this embodiment describes the fourth step in the first embodiment in detail.

[0106] The relative velocity between the slurry and aggregate phases v t , slurry conveying speed v l and aggregate conveying speed v s The methods for establishing the relationship between include:

[0107] Calculate the Reynolds number for concrete, which is a dimensionless number that can be used to characterize fluid flow conditions:

[0108] Calculate the drag coefficient of the slurry on the aggregate, which is related to the Reynolds number:

[0109] Calculate the viscous drag force of slurry on aggregate:

[0110] Calculate the buoyancy of the slurry on the aggregate: Where g is the acceleration due to gravity;

[0111] Calculate the effective weight w of aggregate particles s :

[0112] Calculate the interference force between aggregates:

[0113] Establish the force balance equation of bone particles: G = f d +f b +Kf h ;

[0114] Obtain the relative velocity v between the slurry and aggregate phases t , slurry conveying speed v l and aggregate conveying speed v s The relationship between:

[0115]

[0116] By substituting the above equations into corresponding positions, deriving and simplifying them, the relative velocity of the slurry and aggregate can be obtained.

[0117] Embodiment 3

[0118] This embodiment provides a method for calculating the Swanson shape coefficient in the first and second embodiments.

[0119] Taking into account the influence of the Swanson shape coefficient of the aggregate shape, the calculation method includes:

[0120] Calculate the aggregate area index: Parameters reflecting the shape of solid particles, where b and l are the diameters of the two axes of the aggregate particle space except the longest axis, and d e is the diameter of an imaginary spherical particle of the same mass as the particle.

[0121] Calculate the Swanson shape coefficient α,

[0122] Calculate the Swanson shape coefficient β,

[0123] Calculate the Swanson shape factor n,

[0124] In some cases, in order to speed up the calculation, the Swanson shape coefficient can be approximated directly without considering the influence of aggregate shape, that is, α = 0.6626 and β = 5.368.

[0125] Embodiment 4

[0126] In the above embodiment, the corresponding running speed of aggregate of a certain diameter is calculated and the corresponding running speed is obtained. In order to prevent the segregation of aggregates of other particle sizes in concrete, the second step of the first embodiment is repeated by changing d, d e , C v etc., and calculate the conveying speed of different aggregates.

[0127] Output multiple conveying speeds of aggregates of all particle sizes in the concrete in sequence, take the minimum value of multiple conveying speeds, and output it as the final conveying speed.

[0128] Embodiment 5

[0129] The characteristic of gravity conveying is that it relies on its own gravity to transport concrete from high to low. It is a process of converting potential energy into kinetic energy. In addition to overcoming the friction resistance of the pipeline, most of the conversion is converted into kinetic energy.

[0130] When concrete is continuously fed in a full-pipe laminar flow, the concrete forms a stable columnar fluid in the pipe. The slurry wraps the concrete and lubricates the pipe wall as it slides down. The overall sliding speed is relatively low, there is little relative movement between aggregates, and basically no separation occurs.

[0131] When the concrete is transported in a full pipe with negative pressure (full pipe discontinuous), the concrete falls in the pipe in a short columnar shape. The concrete column is affected by gravity and the difference in air pressure between the upper and lower parts (air support on the lower side), and the falling speed becomes slower. In this state, although the columnar concrete moves in a laminar flow, it is affected by the different pressures of the air above and below, and the concrete interface (the lower end face of the concrete column in the pipe) is prone to water loss and solidification, especially in the first pipe.

[0132] At the same time, when installing the slide pipe, a special gate valve is usually installed between the two slide pipes to control the full pipe flow. The installation position of the gate valve can be determined by controlling the length of the slide pipe, so that the air in the slide pipe can be discharged to avoid segregation. Figure 3 shown.

[0133] Step 1: Calculate negative air pressure Where ρk is the compressed density of the air section between the two concrete sections in the chute;

[0134] Step 2, establish the balanced equation:

[0135] Where v0 is the initial velocity of the concrete, and t is the speed at which the concrete accelerates from v0 to v m time;

[0136] Step 3, establish the equation of motion:

[0137] Step 4, calculate the maximum length of the slide pipe:

[0138] In general, take t≈2s, v0=0.

[0139] Therefore, after solving L, it can be compared with v in the first and second embodiments. m , as an indicator to prevent segregation, the installation and use of the slide pipe is carried out to avoid segregation.

[0140] Embodiment 6

[0141] This embodiment provides a parameter determination system for preventing high-speed concrete from segregating for implementing the above embodiment, including:

[0142] The first input module is used to input the density of the slurry in the concrete l , aggregate density ρ sAs well as the average density ρ of the concrete, the slurry viscosity μ of the concrete, and the inner diameter D of the chute; used to perform the operation of the first step in Example 1.

[0143] The second input module is used to input the aggregate particle size d and the equivalent diameter d of the particle ball in the concrete. e The volume concentration of aggregate with diameter d in the total concrete is C v ; Used to perform the operation of the second step in Example 1.

[0144] The parameter establishment module is used to set the slurry velocity v during the process of falling along the inner wall of the slide pipe. l The aggregate's velocity in the falling process of the chute is v s ; Used to perform the operation of the third step in Example 1.

[0145] Calculation module for establishing the relative velocity v between the slurry and aggregate phases t , slurry conveying speed v l and aggregate conveying speed v s The calculation relationship between:

[0146] Wherein α, β, and n are Swanson shape coefficients, which are used to perform the operation of the fourth step in the first embodiment.

[0147] The third input module is used to input the relative speed v corresponding to the separation judgment standard t , and solve the relationship to obtain v l and v s ; Used to perform the operation of the fifth step of embodiment one.

[0148] The fourth input module is used to input the concrete conveying speed v in the chute. m ;

[0149] The judgment module is used to judge v m <(v s +v l ) / 2;

[0150] The output module is used to output that the concrete delivery speed will not be segregated when the determination module determines that it is yes; when the determination module determines that it is no, output that the concrete delivery speed will be segregated, and re-determine after correcting the delivery speed.

[0151] Here, the three modules are used to perform the operation of the sixth step in the first embodiment.

[0152] All the above modules can be independent calculation modules or multiple calculation steps in one calculation software. After the system is built, the relevant parameters can be directly input and the relevant judgment results can be output.

[0153] Embodiment 7

[0154] The structure in this embodiment is used to execute the relevant steps in the second embodiment, which can be multiple sub-modules in the calculation module, or multiple independent modules can be combined to form a whole. The calculation module includes:

[0155] The first calculation module is used to calculate the Reynolds number of concrete:

[0156] The second calculation module is used to calculate the drag coefficient of the slurry on the aggregate:

[0157] The third calculation module is used to calculate the viscous drag force of the slurry on the aggregate:

[0158] The fourth calculation module is used to calculate the buoyancy of the slurry on the aggregate: Where g is the acceleration due to gravity;

[0159] The fifth calculation module is used to calculate the effective gravity w of aggregate particles s :

[0160] The sixth calculation module is used to calculate the interference force between aggregates:

[0161] Modeling module, used to establish the force balance equation of bone particles: G = f d +f b +Kf h ;

[0162] The seventh calculation module is used to obtain the relative velocity v between the slurry and aggregate phases t , slurry conveying speed v l and aggregate conveying speed v s The relationship between:

[0163]

[0164] Embodiment 8

[0165] This embodiment is used to execute the steps in the fourth embodiment.

[0166] Input the aggregate particle size, particle ball equivalent diameter, and volume concentration of the aggregate in the total concrete of different aggregates in the concrete to the second input module, and output a plurality of different conveying speeds through the parameter establishment module, the calculation module, the third input module, the fourth input module, the determination module, and the output module;

[0167] The parameter determination system also includes:

[0168] The comparison module is used to obtain the minimum value of multiple different sliding speeds and output it as the final sliding speed.

[0169] Embodiment 9

[0170] This embodiment provides a system for executing Embodiment 5, which includes:

[0171] The eighth calculation module is used to calculate the negative air pressure Where ρk is the compressed density of the air section between the two concrete sections in the chute;

[0172] The second modeling module is used to establish the equilibrium equation:

[0173] Where v0 is the initial velocity of the concrete, and t is the speed at which the concrete accelerates from v0 to v m time;

[0174] Establish the equation of motion:

[0175] The ninth calculation module is used to calculate the maximum length of the slide pipe:

[0176] Embodiment 10

[0177] A parameter determination terminal for preventing high-speed concrete from segregating comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the parameter determination method for preventing high-speed concrete from segregating are implemented.

[0178] The memory can be used to store software programs and modules. The processor executes various functional applications and data processing of the terminal by running the software programs and modules stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an execution program required for at least one function, etc.

[0179] The data storage area can store data created according to the use of the terminal, etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0180] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the above-mentioned parameter determination method for preventing segregation of high-speed concrete.

[0181] Without loss of generality, computer readable media may include computer storage media and communication media. Computer storage media include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer readable instruction data structures, program modules or other data. Computer storage media include RAM, ROM, EPROM, EEPROM, flash memory or other solid-state storage technology, CD-ROM, DVD or other optical storage, cassettes, magnetic tapes, disk storage or other magnetic storage devices. Of course, those skilled in the art will appreciate that computer storage media are not limited to the above. The above-mentioned system memory and mass storage devices can be collectively referred to as memory.

[0182] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0183] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0184] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above invention, and these changes or modifications are still within the scope of the present invention.

Claims

1. A method for determining parameters to prevent segregation of high-speed concrete, characterized in that: include: Input the density of the slurry in the concrete ρ l , aggregate density ρ s and the average density of concrete, ρ; Input the aggregate particle size d and the equivalent diameter of the particle ball d in the concrete e ; The volume concentration C of aggregate with input aggregate size d in the total concrete v ; Input concrete slurry viscosity μ; The inner diameter D of the input slide pipe; Let the slurry flow velocity along the inner wall of the slide pipe be v l The aggregate's velocity in the falling process of the chute is v s ; Establish the relative velocity v between the slurry and aggregate phases t , slurry conveying speed v l and aggregate conveying speed v s The calculation relationship between: Where α, β, and n are Swanson shape coefficients; Input the relative speed v corresponding to the separation judgment standard t , and solve the relationship to obtain v l and v s ; Enter the concrete conveying speed v in the chute m , and determine v m <(v s +v l ) / 2, if yes, then the output concrete will not segregate when it is fed at this feeding speed; if no, then the output concrete will segregate when it is fed at this feeding speed, and the judgment will be made again after the feeding speed is corrected; Output multiple conveying speeds of aggregates of all particle sizes in the concrete in sequence, and take the minimum value of the multiple conveying speeds as the final conveying speed; Calculate negative air pressure where ρ k is the compressed density of the air section between the two concrete sections in the chute; Create the balanced equation: Where v0 is the initial velocity of the concrete, and t is the speed at which the concrete accelerates from v0 to v m time; Establish the equation of motion: Calculate the maximum length of the slide pipe:

2. A parameter determination method for preventing high-speed concrete from segregating according to claim 1, characterized in that: The relative velocity between the slurry and aggregate phases v t , slurry conveying speed v l and aggregate conveying speed v s The methods for establishing the relationship between include: Calculate the Reynolds number for concrete: Calculate the drag coefficient of slurry on aggregate: Calculate the viscous drag force of slurry on aggregate: Calculate the buoyancy of the slurry on the aggregate: Where g is the acceleration due to gravity; Calculate the effective gravity of aggregate particles Calculate the interference force between aggregates: Establish the force balance equation of bone particles: G = f d +f b +Kf h ; Obtain the relative velocity v between the slurry and aggregate phases t , slurry conveying speed v l and aggregate conveying speed v s The relationship between:

3. A parameter determination method for preventing high-speed concrete from segregating according to claim 2, characterized in that: The calculation method of Swanson shape factor includes: Calculate the aggregate area index: Where b and l are the axial diameters of the two axes of the aggregate particle space except the longest axis; Calculate the Swanson shape coefficient α, Calculate the Swanson shape coefficient β, Calculate the Swanson shape factor n, 4. A parameter determination method for preventing high-speed concrete from segregating according to claim 3, characterized in that: The α=0.6626 and β=5.

368.

5. A parameter determination method for preventing high-speed concrete from segregating according to claim 1, characterized in that: t≈2s, v0=0.

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