A method for predicting pump blockage during ultra-high lift concrete pumping

Abstract

The present invention discloses a method for predicting pump blockage during ultra-high lift concrete pumping. The present invention includes the following steps: S1. Before pumping, obtain the viscosity resistance coefficient of the concrete mixture to be pumped and conduct an initial pumpability evaluation; S2. During each pumping process, obtain the real-time viscosity resistance coefficient of the concrete mixture in the pump pipe and conduct a pumpability evaluation; S3. Based on the ratio of the real-time viscosity resistance coefficient of the concrete mixture in the pump pipe to the viscosity resistance coefficient of the concrete mixture, use it as a risk coefficient to predict pump blockage. By monitoring the real-time pump pressure during the pumping process of the concrete mixture and obtaining the pump pressure change risk coefficient through analysis and calculation, it is possible to predict, pre-judge, and give early warnings about the pump blockage problem of the concrete mixture, provide quantitative data basis and support for timely disposal, avoid the occurrence of pump blockage problems, improve the pumping construction efficiency, and avoid and reduce economic losses.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and specifically relates to a method for predicting pump blockage during ultra-high elevation concrete pumping. Background Art

[0002] Pumping construction is to transport the cement concrete mixture to the upper end face of the structure for pouring construction through a concrete delivery pump and pump pipes. The working pressure of the concrete delivery pump is greatly affected by the resistance of the concrete mixture in the conveying pipeline. The greater the pumping resistance, the greater the corresponding working pressure required to maintain the smooth progress of concrete pumping. When the pumping resistance is greater than the maximum working pressure of the concrete delivery pump, a pump blockage phenomenon occurs. The resistance of concrete in the conveying pipeline is affected by, on the one hand, the fluidity, viscosity, lubricity, homogeneity, and stability of the concrete mixture itself. The smaller the fluidity, the more viscous, the poorer the lubricity, and the greater the segregation and bleeding of the concrete mixture, the greater its pumping resistance; on the other hand, it is affected by the internal surface roughness of the conveying pipe. The rougher the inner surface of the pipe, the greater the pumping resistance; on the third hand, it is affected by the shape of the conveying pipe. The more elbows, the greater the pumping resistance; on the fourth hand, it is affected by the sealing performance at the joints of the conveying pipes. The poorer the sealing performance, it is easy to cause the precipitation in the concrete mixture to overflow from the joints, resulting in the concrete mixture in the pipe becoming dry and thick due to excessive water loss, and the pumping resistance increases. When the pumping resistance changes, in order to maintain pumping, the corresponding working pressure of the concrete delivery pump will also change accordingly.

[0003] After investigation, currently, during the concrete pumping construction process, there is no method for quantitatively analyzing and evaluating the lubrication and resistance reduction properties and pumpability of the concrete mixture, and there is no effective way to timely monitor, predict, and warn of pump blockage during ultra-high elevation concrete pumping. Often, when the concrete delivery pump increases to a certain extent and it is found that the concrete cannot be pumped, measures are taken to eliminate the pump blockage. However, due to the often long pump pipes and large vertical drop in ultra-high elevation pumping, the back thrust generated by the self-gravity of the concrete in the pipe is relatively large. Once the pump pipes are removed for dredging, the concrete in the vertical pipes will flow down due to self-gravity, resulting in a large empty layer in the conveying pipe. After the blocked pipe is cleaned and dredged and pumping is carried out again under pressure, the water and slurry in the concrete in the pipe will be lost due to compressed air, making it even drier and thus unable to discharge the pump blockage.

[0004] The unpredictability and risk of pumping construction are increased. Maybe there is no problem with this pumping construction, or maybe due to the excessive loss value of the pumping pressure spread of the cement concrete mixture during the pumping construction process, the pouring difficulty is increased, and even pump blockage occurs, resulting in the interruption of the construction, and a large amount of manpower and material resources are consumed to handle it, causing unnecessary quality and economic losses. To achieve early prediction and pre-control of pump blockage during concrete pumping is a key problem that urgently needs to be solved in the current concrete pumping construction control, especially for the control of ultra-long and ultra-high elevation pumping construction. Summary of the Invention

[0005] The object of the present invention is to address the above deficiencies and provide a method for predicting pump blockage during ultra-high elevation concrete pumping. By observing the dynamic change amount of the working pressure of the concrete delivery pump in real time during concrete pumping, analyzing and processing the change trend of the pump pressure to obtain the pump pressure change risk coefficient, which is used to predict whether pump blockage will occur during concrete pumping.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for predicting pump blockage during ultra-high elevation concrete pumping, comprising the following steps:

[0008] S1. Before pumping, obtain the viscosity resistance coefficient of the concrete mixture to be pumped and conduct an initial pumpability evaluation;

[0009] S2. During each pumping process, obtain the real-time viscosity resistance coefficient of the concrete mixture in the pump pipe and conduct a pumpability evaluation;

[0010] S3. Based on the ratio of the real-time viscosity resistance coefficient of the concrete mixture in the pump pipe to the viscosity resistance coefficient of the concrete mixture as the risk coefficient for predicting pump blockage, and the prediction criteria are as follows:

[0011] When the risk coefficient is less than 2, the pump blockage risk of the concrete mixture pumping construction is at the safe level;

[0012] When the risk coefficient of one of the observations is greater than or equal to 2, the pump blockage risk of the concrete mixture pumping construction is at the vigilant level, and the observation frequency should be increased;

[0013] When the risk coefficients of more than two consecutive observations are all greater than 2, the pump blockage risk of the concrete mixture pumping construction is at the high-risk level, and the pumping construction should be stopped immediately for investigation and treatment until the risk coefficient is less than 2.

[0014] Specifically, in step S1 of the present invention, the process of obtaining the viscosity resistance coefficient of the concrete mixture to be pumped before pumping and conducting an initial pumpability evaluation includes:

[0015] Conduct a slump emptying test on the concrete to be pumped, measure the slump cone emptying time and spread of the concrete, and calculate the annual resistance index of the concrete through the measured slump cone emptying time and spread data. The annual resistance index calculation formula is as follows:

[0016]

[0017] In the formula:

[0018] β1 ─ Viscosity resistance index;

[0019] T P─Emptying time of the inverted slump cone;

[0020] d K ─Slump flow;

[0021] Wherein,

[0022] When the viscosity resistance index β1 < 30, the lubrication and resistance reduction property of the concrete mixture is excellent, and the pumpability grade is Grade I;

[0023] When the viscosity resistance index β1 ≥ 30 and < 50, the lubrication and resistance reduction property of the concrete mixture is good, and the pumpability grade is Grade II;

[0024] When the viscosity resistance index β1 ≥ 50 and < 80, the lubrication and resistance reduction property of the concrete mixture is medium, and the pumpability grade is Grade III;

[0025] When the viscosity resistance index β1 ≥ 80, the lubrication and resistance reduction property of the concrete is poor, and the pumpability is unqualified.

[0026] Specifically, in step S2 of the present invention, the process of obtaining the real-time viscosity resistance coefficient of the concrete mixture in the pump pipe during each pumping process and performing pumpability evaluation includes:

[0027] S201. According to the construction design, configure the pumping equipment, the pumping equipment includes a concrete pump and a delivery pipe, and estimate the elbow pressure and the self-gravity of the concrete in the vertical pipe according to the configuration plan;

[0028] S202. Install the pumping equipment to the pouring surface, after checking and preparing the pumping equipment, pump the concrete;

[0029] S203. After pumping the concrete mixture to the pouring surface, record the real-time working pressure of the concrete pump for each pumping of the concrete, and calculate the pumping frictional pressure loss;

[0030] S205. Calculate the real-time viscosity resistance coefficient of the concrete mixture based on the real-time frictional pressure loss and the flow velocity of the concrete mixture in the pump pipe, and its calculation formula is as follows:

[0031]

[0032] In the formula:

[0033] β i —Is the real-time viscosity resistance coefficient of the concrete mixture in the pump pipe;

[0034] P Li —Pumping frictional pressure loss;

[0035] S B ─Cross-sectional area of the pump pipe;

[0036] V c─ Flow velocity of the concrete mixture in the pump pipe;

[0037] Among them: The flow velocity V of the concrete mixture in the pump pipe c Is calculated by the following formula:

[0038]

[0039] In the formula:

[0040] V ─ Flow velocity of the concrete mixture in the pump pipe;

[0041] V B ─ Pumping frequency of the concrete pump;

[0042] S B ─ Cross-sectional area of the pump pipe;

[0043] N B ─ Pumping frequency of the concrete pump.

[0044] Specifically, in step S202 of the present invention, the real-time working pressure of each concrete pump is recorded, and the calculation formula for the actual pumping frictional pressure loss is:

[0045] P Li = P i - P w - P Z

[0046] In the formula:

[0047] P Li — Actual pumping frictional pressure loss;

[0048] P i — Actual working pressure of the concrete pump;

[0049] P w — Estimated elbow pressure;

[0050] P Z — Estimated self-weight of concrete in the vertical pipe.

[0051] Specifically, the calculation formula for the estimated elbow pressure in the present invention is

[0052] P w = 0.1·N W

[0053] In the formula:

[0054] P w ─ Elbow pressure;

[0055] N W ─ Number of elbows.

[0056] Specifically, the calculation formula for the self - gravity of concrete in the vertical pipe of the present invention is:

[0057] P Z = 9.8·ρ C ·H

[0058] In the formula:

[0059] P Z ─ The self - gravity of concrete in the vertical pipe;

[0060] ρ C ─ The apparent density of the concrete mixture.

[0061] Specifically, in step S201 of the present invention, when configuring the selection of pumping equipment, the rated working pressure of the concrete pump should not be less than the total conveying pressure, and the calculation formula for the total conveying pressure is:

[0062] P0 = P w +P Z +P L

[0063] In the formula:

[0064] P0 — The total conveying pressure;

[0065] P w — The estimated elbow pressure;

[0066] P Z — The estimated self - gravity of concrete in the vertical pipe;

[0067] P L — The estimated frictional pressure loss;

[0068] Among them, the estimated calculation formula for the frictional pressure loss is:

[0069] P L = △P L ·L

[0070] In the formula:

[0071] P L ─ The frictional pressure loss;

[0072] L ─ The equivalent total horizontal pipe length;

[0073] △P L ─ The frictional pressure loss per 1 m of the concrete mixture in the pipe;

[0074] Among them: The estimated calculation formula for the frictional pressure loss per 1 m of the concrete mixture in the pipe is:

[0075]

[0076] In the formula:

[0077] r ─ Radius of the pump pipe;

[0078] β1 ─ Viscous resistance index;

[0079] β2 ─ Flow velocity index;

[0080] V c ─ Flow velocity of the concrete mixture in the pump pipe;

[0081] Among them, the calculation formula for the flow velocity index is:

[0082] β2 = β1 + 100

[0083] In the formula:

[0084] β1 ─ Viscous resistance index;

[0085] β2 ─ Flow velocity index;

[0086] Among them, the calculation formula for the flow velocity of the concrete mixture in the pump pipe is as follows:

[0087]

[0088] In the formula:

[0089] V ─ Flow velocity of the concrete mixture in the pump pipe;

[0090] V B ─ Pumping frequency of the concrete pump;

[0091] S B ─ Cross-sectional area of the pump pipe;

[0092] N B ─ Pumping frequency of the concrete pump.

[0093] Specifically, in step S202 of the present invention: after installing the pumping equipment, after checking that there is no foreign matter in the concrete pump and the conveying pipe, first pump clear water to check the connection tightness of the pipeline to ensure that there is no leakage in the pipeline connection, and then pump lubricating slurry to lubricate the inner walls of the concrete pump and the conveying pipe. After the conveying pipe is fully lubricated, finally pump the concrete.

[0094] The present invention has the following advantages:

[0095] 1. By detecting the slump and spread of the concrete mixture, and monitoring the real-time pump pressure during the pumping process of the concrete mixture, the viscous resistance index obtained through analysis and calculation processing can be used to quantitatively analyze and evaluate the lubrication and resistance reduction properties and pumpability of the concrete mixture, so that the concrete mixture can be processed in advance, which helps to prevent, reduce and avoid the occurrence of pump blockage problems, improve the pumping construction efficiency, and achieve the effect of treating diseases before they occur.

[0096] 2. Monitoring the real-time pump pressure during the pumping process of the concrete mixture, obtaining the pump pressure change risk coefficient through analysis and calculation, which can predict, pre-judge and give early warning of the pumping blockage problem of the concrete mixture, provide quantitative data basis and support for timely disposal, avoid the occurrence of pumping blockage problems, improve the pumping construction efficiency, and avoid and reduce economic losses. Brief Description of the Drawings

[0097] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0098] The present invention will be further described below with reference to the drawings:

[0099] Figure 1 It is a process schematic diagram of the present invention. Detailed Embodiments

[0100] It should be understood that in the description of the embodiments of the present invention, words such as "first" and "second" are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In the embodiments of the present invention, "a plurality of" means two or more.

[0101] The "and / or" in the embodiments of the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and A and B exist simultaneously. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0102] This embodiment provides a method for predicting pumping blockage in ultra-high elevation concrete pumping, including the following steps:

[0103] S1. Obtain the viscosity resistance coefficient of the concrete mixture to be pumped before pumping and conduct an initial pumpability evaluation;

[0104] The calculation process is as follows: Conduct a slump emptying test on the concrete to be pumped, measure the slump cone emptying time and spread of the concrete, and calculate the annual resistance index of the concrete through the measured slump cone emptying time and spread data. The annual resistance index calculation formula is as follows:

[0105]

[0106] In the formula:

[0107] β1 - adhesion resistance index;

[0108] T P - the emptying time of the inverted slump cone;

[0109] d K - the spread;

[0110] Among them, the criteria for evaluating pumpability are:

[0111] When the adhesion resistance index β1 < 30, the lubrication and resistance reduction of the concrete mixture is excellent, and the pumpability grade is Grade I;

[0112] When the adhesion resistance index β1 ≥ 30 and < 50, the lubrication and resistance reduction of the concrete mixture is good, and the pumpability grade is Grade II;

[0113] When the adhesion resistance index β1 ≥ 50 and < 80, the lubrication and resistance reduction of the concrete mixture is medium, and the pumpability grade is Grade III;

[0114] When the adhesion resistance index β1 ≥ 80, the lubrication and resistance reduction of the concrete is poor, and the pumpability is unqualified.

[0115] S2. According to the construction design, configure the pumping equipment. The pumping equipment includes a concrete pump and a delivery pipe, and estimate the elbow pressure, the self - weight of the concrete in the vertical pipe, the estimated frictional pressure loss, and the total delivery pressure according to the configuration plan. The rated working pressure of the concrete pump should not be less than the total delivery pressure.

[0116] (1) The calculation formula for estimating the elbow pressure is

[0117] P w = 0.1·N W (2)

[0118] In the formula:

[0119] P w - the elbow pressure;

[0120] N W - the number of elbows.

[0121] (2) The calculation formula for estimating the self - weight of the concrete in the vertical pipe is:

[0122] P Z = 9.8·ρ C ·H (3)

[0123] In the formula:

[0124] P Z - the self - weight of the concrete in the vertical pipe;

[0125] ρ C─ Apparent density of concrete mixture.

[0126] (3) The estimated calculation formula for the estimated frictional pressure loss is:

[0127] P L = △P L ·L (4)

[0128] Where:

[0129] P L ─ Frictional pressure loss;

[0130] L─ Equivalent total horizontal pipe length;

[0131] △P L ─ Frictional pressure loss per 1m of concrete mixture in the pipe;

[0132] Among them: The estimated calculation formula for the frictional pressure loss per 1m of concrete mixture in the pipe is:

[0133]

[0134] Where:

[0135] r─ Radius of the pump pipe;

[0136] β1─ Viscous resistance index;

[0137] β2─ Flow velocity index;

[0138] V c ─ Flow velocity of concrete mixture in the pump pipe;

[0139] Among them, the calculation formula for the flow velocity index is:

[0140] β2 =β1 + 100 (6)

[0141] Where:

[0142] β1─ Viscous resistance index;

[0143] β2─ Flow velocity index;

[0144] Among them, the calculation formula for the flow velocity of concrete mixture in the pump pipe is as follows:

[0145]

[0146] Where:

[0147] V─ Flow velocity of concrete mixture in the pump pipe;

[0148] V B ─ Pumping frequency of the concrete pump;

[0149] SB ─ Cross-sectional area of the pump pipe

[0150] N B ─ Pumping frequency of the concrete pump

[0151] (4) The calculation formula for the total conveying pressure is:

[0152] P0 = P w + P Z + P L (8)

[0153] Where:

[0154] P0—Total conveying pressure

[0155] P w —Estimated elbow pressure

[0156] P Z —Estimated self-weight of concrete in the vertical pipe

[0157] P L —Estimated frictional pressure loss

[0158] S3. Install the pumping equipment to the pouring surface. After checking that there is no foreign matter in the concrete pump and the conveying pipe, first pump clear water to check the connection tightness of the pipeline to ensure that there is no leakage in the pipeline connection. Then pump lubricating slurry to lubricate the inner walls of the concrete pump and the conveying pipe. After all the conveying pipes are lubricated, finally pump the concrete.

[0159] S4. After pumping the concrete mixture to the pouring surface, record the real-time working pressure of the concrete pump for each pumping of concrete within 5 minutes, and calculate the frictional pressure loss during pumping. The calculation formula for calculating the frictional pressure loss is:

[0160] P Li = P i -P w -P Z (9)

[0161] Where:

[0162] P Li —Actual frictional pressure loss during pumping

[0163] P i —Actual working pressure of the concrete pump

[0164] P w —Estimated elbow pressure

[0165] P Z —Estimated self-weight of concrete in the vertical pipe

[0166] S5. During each pumping process, obtain the real-time viscosity resistance coefficient of the concrete mixture in the pump pipe, and conduct a pumpability evaluation. The process of conducting the pumpability evaluation refers to step S1. Among them, calculate the real-time viscosity resistance coefficient of the concrete mixture based on the real-time frictional pressure loss and the flow rate of the concrete mixture in the pump pipe. The calculation formula is as follows:

[0167]

[0168] In the formula:

[0169] β i — is the real-time viscosity resistance coefficient of the concrete mixture in the pump pipe;

[0170] P Li — Frictional pressure loss during pumping;

[0171] S B ─ Cross-sectional area of the pump pipe;

[0172] V c ─ Flow rate of the concrete mixture in the pump pipe;

[0173] Among them: The flow rate V of the concrete mixture in the pump pipe c Is calculated using formula 7.

[0174] S6. Based on the ratio of the real-time viscosity resistance coefficient of the concrete mixture in the pump pipe to the viscosity resistance coefficient of the concrete mixture as the risk coefficient λ Bi Conduct a prediction of pump blockage. The calculation formula is:

[0175]

[0176] The prediction criteria are as follows:

[0177] When λ Bi Is less than 2, the pump blockage risk of the concrete mixture pumping construction is at the safe level;

[0178] When λ observed once Bi Is greater than or equal to 2, the pump blockage risk of the concrete mixture pumping construction is at the warning level, and the observation frequency should be increased;

[0179] When λ observed continuously for more than 2 times Bi Are all greater than 2, the pump blockage risk of the concrete mixture pumping construction is at the high-risk level. Pumping construction should be stopped immediately for inspection and treatment until λ Bi Is less than 2.

[0180] Based on the above process, for the convenience of understanding the technical solution of this application, the method of the present invention will be further described in detail through one of the construction examples below:

[0181] 1. In a certain project, a slump flow evacuation test was conducted on the concrete mixture to measure the slump cone evacuation time T of the concrete mixture entering the pump. P The slump cone evacuation time T was 4 s, and the spread value d K was 650. Substitute these values into formula (1) to calculate the viscosity resistance index β. i The calculated viscosity resistance index β was 24.6. When the viscosity resistance index β i <30, the lubrication and resistance reduction performance of the concrete mixture is excellent, and the pumpability grade is Grade I.

[0182] 2. Pumping equipment configuration:

[0183] (1) The elbow settings are shown in Table 1.

[0184] Table 1 Elbow settings

[0185]

[0186] Substitute the values into the formula (2) to calculate the elbow pressure P. w The calculated elbow pressure P was 0.9 MPa.

[0187] (2) The vertical pipe settings are shown in Table 2.

[0188] Table 2 Vertical pipe settings

[0189] Position of pump pipe Type of pump pipe Pipe length (m) / piece Total number of pipes Pipe length (m) Horizontal Horizontal pipe 3 35 105 Vertical Vertical pipe 3 130 390

[0190] The strength grade was C60, and the apparent density ρ of the concrete mixture C was 2450 kg / m 3 . Substitute these values into formula (3) to calculate the self - gravity P of the concrete in the vertical pipe. Z The calculated self - gravity P of the concrete in the vertical pipe was 9.4 MPa.

[0191] (3) Horizontal pipe configuration and calculation of the frictional pressure loss P L , and the horizontal pipe settings are shown in Table 3.

[0192] Table 3 Horizontal pipe settings

[0193]

[0194] The flow velocity V of the concrete mixture in the pump pipe c , calculated according to formula (7), is shown in Table 4.

[0195] Table 4 Flow velocity measurement

[0196]

[0197] Calculate the flow velocity index β2 according to the above formula (6). After calculation, the flow velocity index β2 was 124.6 S / mm.

[0198] (4) Other parameters are shown in Table 5.

[0199] Table 5 Other parameters

[0200]

[0201] Substitute the above data into the above formula (5) to calculate the pressure loss △P per 1 m along the pipe for the fresh concrete mixture L , and through calculation, the pressure loss △P per 1 m along the pipe for the fresh concrete mixture is obtained L as 2058.285 Pa

[0202] Calculate the pressure loss P along the pipe according to the above formula (4) L , and through calculation, the pressure loss P along the pipe is obtained L as 4.5 MPa

[0203] The stable pumping pressure P0 is calculated according to the above formula (8), and through calculation, the stable pumping pressure P0 is obtained as 14.8 MPa

[0204] 3. Install the concrete pump and the conveying pipe. After confirming that there are no foreign objects in the concrete pump and the conveying pipe, first pump clear water to check the tightness of the pipeline. If there is no water leakage in the pipeline, it means that the pipeline tightness is good. Then pump lubricating slurry to lubricate the inner walls of the concrete pump and the conveying pipe, and then pump the fresh concrete mixture

[0205] 4. After pumping the fresh concrete mixture to the pouring surface, observe and record the real-time working pressure P of the concrete pump for each push of concrete within 5 minutes i as 15.2 MPa

[0206] Calculate the real-time pressure loss P along the pipe according to formula (9) Li , and through calculation, the real-time pressure loss P along the pipe is obtained Li as 4.9 MPa

[0207] 5. Calculate the real-time viscosity resistance index β through the above formula (10) i , and through calculation, the real-time viscosity resistance index β is obtained i as 30.8 S / mm, and the lubrication resistance reduction property is good

[0208] 6. Calculate the risk coefficient λ of pump pressure change according to formula (11) Bi ,

[0209] Through calculation, the risk coefficient λ of pump pressure change is obtained Bi as 1.25. When λ Bi is less than 2, the risk of pump blockage during the pumping construction of the fresh concrete mixture is at the safe level

[0210] 7. Continuously observe and record the real-time working pressure P of the concrete pump for each push of concrete iis 18.5MPa, calculated according to the above method: real-time extended pressure loss P Li is 8.2MPa, and the real-time viscosity resistance index β i is 73.4S / mm, and the risk factor of pump pressure change is λ Bi is 2.98, when the λ of a certain observation Bi When it is not less than 2, the risk of pump blockage in concrete mixture pumping construction is at the warning level, and the frequency of observation should be increased.

[0211] 8. Observe three times in succession and obtain the data shown in Table 6.

[0212] Table 6 List of real-time pump pressure observation processing results The risk was discovered but not dealt with in a timely manner, resulting in pump blockage.

[0213] 9. After the pump pipe is unblocked and reinstalled, pump concrete again, and observe and record the real-time working pressure P of the concrete pump each time it pushes concrete. i is 15.5MPa, calculated according to the above method: real-time extended pressure loss P Li is 5.2MPa, and the real-time viscosity resistance index β i is 34.7S / mm, lubrication resistance reduction is good, pumpability is level II, and pump pressure change risk coefficient λ Bi The value is 1.41, and the risk of pump blockage in concrete mixture pumping construction is at a safe level.

[0214] 10. Continue and record the real-time working pressure P of the concrete pump each time it pushes concrete. i is 18.0MPa, calculated according to the above method: real-time extended pressure loss P Li is 7.7MPa, the real-time viscosity resistance index βi is 67.7S / mm, and the pump pressure change risk coefficient λ Bi is 2.72, when the λ of a certain observation Bi When the pressure is not less than 2, the risk of pump blockage in concrete mixture pumping construction is at the alert level. Take timely measures to eliminate the fault and immediately reverse the pump. Open the valve under the concrete pump bucket. It is found that the concrete leaking from the bottom of the pump bucket is dry. Continue to reverse the pump until the leaked concrete has good fluidity. Then close the check valve, clean and close the valve under the concrete pump bucket, open the check valve, switch to forward pumping, and continue to observe and record the real-time working pressure P of the concrete pump each time it pushes concrete. i is 14.8MPa, calculated according to the above method: real-time extended pressure loss P Li is 4.5MPa, real-time viscosity resistance index β i is 25.6S / mm, lubrication resistance reduction is good, pumpability is level II, and pump pressure change risk coefficient λ BiIt is 1.04, and the risk of concrete mixture pumping construction blocking the pump is at the safety level.

[0215] The above-described embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A method for predicting pump blockage during ultra-high lift concrete pumping, characterized in that: It includes the following steps: S1. Obtain the viscosity resistance index of the concrete mixture to be pumped before pumping, and conduct an initial pumpability evaluation; The specific process includes: conducting a slump flow evacuation test on the concrete to be pumped, measuring the slump cone evacuation time and spread of the concrete, and calculating the viscosity resistance index of the concrete based on the measured slump cone evacuation time and spread data. The formula for calculating the viscosity resistance index is as follows: ； In the formula: β1 ─ Viscosity resistance index; T P ─Emptying time of the inverted slump cone; d K - Degree of expansion; Wherein, When the viscosity resistance index β1 < 30, the lubrication and resistance reduction property of the concrete mixture is excellent, and the pumpability grade is grade I; When the viscosity resistance index β1 ≥ 30 and < 50, the lubrication and resistance reduction property of the concrete mixture is good, and the pumpability grade is grade II; When the viscosity resistance index β1 ≥ 50 and < 80, the lubrication and resistance reduction property of the concrete mixture is medium, and the pumpability grade is grade III; When the viscosity resistance index β1 ≥ 80, the lubrication and resistance reduction property of the concrete is poor, and the pumpability is unqualified; S2. Obtain the real-time viscosity resistance index of the concrete mixture in the pump pipe during each pumping process, and conduct a pumpability evaluation; The specific process includes: S201. According to the construction design, configure the pumping equipment, which includes a concrete delivery pump and a delivery pipe, and estimate the elbow pressure and the self-weight of the concrete in the vertical pipe according to the configuration plan; S202. Install the pumping equipment to the pouring surface. After inspecting and preparing the pumping equipment, pump the concrete; S203. After pumping the concrete mixture to the pouring surface, record the real-time working pressure of the concrete pump for each pumping of the concrete, and calculate the pumping frictional pressure loss; S205. Calculate the real-time viscosity resistance index of the concrete mixture based on the real-time frictional pressure loss and the flow rate of the concrete mixture in the pump pipe. The formula is as follows: ； In the formula: β i — is the real-time viscosity resistance index of the concrete mixture in the pump pipe; P Li — Frictional pressure loss during pumping; S B - cross-sectional area of the pump pipe; V c ─ Flow velocity of the concrete mixture in the pump pipe; Wherein: the flow velocity V of the concrete mixture in the pump pipe c is calculated by the following formula: ； In the formula: V c ─ Flow velocity of the concrete mixture in the pump pipe; V B ─ Pumping frequency of the concrete pump S B - cross-sectional area of the pump pipe; N B ─ Pumping frequency of the concrete pump S3. Use the ratio of the real-time viscosity resistance index of the concrete mixture in the pump pipe to the viscosity resistance index of the concrete mixture as the risk coefficient to predict pump blockage. The prediction criteria are as follows: When the risk coefficient is less than 2, the pump blockage risk of the concrete mixture pumping construction is at the safe level; When the risk coefficient of one of the observations is greater than or equal to 2, the pump blockage risk of the concrete mixture pumping construction is at the vigilant level, and the observation frequency should be increased; When the risk coefficients of more than two consecutive observations are all greater than 2, the pump blockage risk of the concrete mixture pumping construction is at the high-risk level. Pumping construction should be stopped immediately for inspection and treatment until the risk coefficient is less than 2.

2. The method according to claim 1, characterized in that: In step S202, the formula for recording the real-time working pressure of the concrete pump for each pumping of the concrete and calculating the actual pumping frictional pressure loss is: P Li = P i -P w -P Z In the formula: P Li — Actual frictional pressure loss during pumping; P i — actual working pressure of the concrete pump; P w — Estimate elbow pressure; P Z — Estimate the self-weight of the concrete in the vertical pipe.

3. The method according to claim 1, wherein: The formula for estimating the elbow pressure is: P w = 0.1·N W In the formula: P w - Elbow pressure; N W - Number of elbows.

4. The method according to claim 1, wherein: The formula for estimating the self-weight of the concrete in the vertical pipe is: P Z = 9.8 · ρ C · H In the formula: P Z ─ Self - gravity of concrete in the vertical pipe; ρ C ─ Apparent density of fresh concrete mixture.

5. The method according to claim 1, wherein: In step S201, when selecting the type of pumping equipment, the rated working pressure of the concrete delivery pump should not be less than the total delivery pressure. The formula for the total delivery pressure is: P0 = P w + P Z + P L In the formula: P0 ─ Total delivery pressure; P w — Estimate elbow pressure; P Z — Estimate the self - gravity of the concrete in the vertical pipe; P L — Estimated frictional pressure loss; Wherein, the formula for estimating the frictional pressure loss is: P L = ΔP L ·L In the formula: P L - Frictional pressure loss; L ─ Equivalent total horizontal pipe length; △P L ─ Pressure loss per 1 m along the pipe for the fresh concrete mixture; Wherein: The formula for estimating the frictional pressure loss per 1m of the concrete mixture in the pipe is: ； In the formula: r ─ Radius of the pump pipe β1 - Cohesion resistance index; β2 - Flow velocity index; V c ─ Flow velocity of the concrete mixture in the pump pipe; Among them, the calculation formula of the flow velocity index is: β2 = β1 + 100 In the formula: β1 - Cohesion resistance index; β2 - Flow velocity index; Among them, the calculation formula of the flow velocity of the concrete mixture in the pump pipe is as follows: ； In the formula: V c - Flow velocity of the concrete mixture in the pump pipe; V B ─ Pumping frequency of the concrete pump S B - cross-sectional area of the pump pipe; N B - Pumping frequency of the concrete pump.

6. The method according to claim 1, wherein: In step S202: After installing the pumping equipment, after checking that there is no foreign matter in the concrete pump and the conveying pipe, first pump clear water to check the connection tightness of the pipeline to ensure that there is no leakage in the pipeline connection, and then pump lubricating slurry to lubricate the inner walls of the concrete pump and the conveying pipe. After all the conveying pipes are lubricated, finally pump the concrete.

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