Real-time temperature analysis and simulation method and system based on warehouse jumping method

Abstract

The invention relates to the technical field of building construction simulation, in particular to a real-time temperature analysis simulation method and system based on a warehouse jumping method. The method comprises the following steps: acquiring basic raft composition data and related construction specifications; calculating a concrete tensile strength change trend according to the obtained basic raft composition data; according to related construction specifications of the basic raft composition data, calculating a time-varying relationship of the elastic modulus of the concrete; constructing two adjacent basic raft plate models by utilizing a Midas Gen finite element model; carrying out skip method pouring simulation on the two adjacent concrete bottom models, and carrying out analytical calculation; and obtaining an analysis result. The method solves the problem that in the prior art, due to the complex thermal boundary condition, the temperature field of concrete separate bin pouring is difficult to analyze.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction simulation, and in particular to a real-time temperature analysis simulation method and system using a skip bin method. Background Art

[0002] At present, the "skip bin method" construction scheme is gradually increasing in the process of pouring large-volume concrete. The skip bin method refers to: in the construction of large-volume concrete structures, in the early stage of large temperature shrinkage stress, the super-long concrete block is divided into several small blocks for interval construction, and after a short period of stress release, the several small blocks are connected into a whole in the later stage of small shrinkage stress, relying on the tensile strength of concrete to resist the temperature shrinkage stress of the next stage.

[0003] During the construction process of the skip bin method, the construction interval between bins determines the interaction between the temperature and deformation of the bins. At present, the calculation process of the "skip bin method" construction simulation, the temperature field of large-volume concrete is mostly completed in the laboratory by software. The selected calculation parameters such as ambient temperature, ambient humidity, concrete pouring temperature, concrete mix ratio and other parameters are mostly based on the average temperature of previous years or previous concrete data, which are different from the actual situation on site. This has caused great difficulty in the temperature field analysis of concrete bin pouring. Summary of the invention

[0004] In order to solve the above-mentioned problems, the present invention provides a real-time temperature analysis simulation method and system using a skip bin method, so as to solve the difficulty of concrete pouring temperature field analysis in the current technology.

[0005] In the first aspect, the present invention provides a real-time temperature analysis simulation method using a skip bin method, which adopts the following technical solution:

[0006] A real-time temperature analysis simulation method using a skip bin method, comprising:

[0007] Obtain foundation raft composition data and relevant construction specifications;

[0008] Calculate the variation trend of concrete tensile strength based on the obtained foundation raft composition data;

[0009] According to the relevant construction specifications of the foundation raft composition data, the relationship between the elastic modulus of concrete and time is calculated;

[0010] The Midas Gen finite element model was used to construct two adjacent foundation raft models;

[0011] The skip-bin method pouring simulation and analysis calculation were carried out on two adjacent concrete bottom models;

[0012] Get the analysis results.

[0013] Furthermore, the obtaining of foundation raft composition data and related construction specifications includes obtaining the concrete mix ratio according to the concrete mix ratio test results provided by the manufacturer, and obtaining relevant thermodynamic references for hydration heat calculation during the foundation slab construction phase based on the concrete structure design specifications and mass concrete construction specifications.

[0014] Furthermore, the variation trend of the tensile strength of concrete is calculated based on the obtained foundation raft composition data, including using the mass concrete construction standard as a reference for the variation of the elastic modulus and strength of concrete over time. The variation trend of the tensile strength of concrete is expressed as:

[0015] f tk (t) = f tk (1-e -γt )

[0016] Where: f tk (t) is the standard value of tensile strength at age t; f tk is the standard value of tensile strength of concrete, and γ is the coefficient taken as 0.3.

[0017] Furthermore, the calculation of the relationship between the elastic modulus of concrete and time according to the relevant construction specifications of the foundation raft composition data includes determining the relationship between the elastic modulus of concrete and time according to the mass concrete specification:

[0018]

[0019] β=β 1 ×β 2

[0020] Where: E(t) is the elastic modulus at age t; E 0 is the elastic modulus of concrete after 28 days of curing; is the coefficient, which is taken as 0.09; β is the correction coefficient of the elastic modulus of the admixture in concrete.

[0021] Furthermore, the use of the Midas Gen finite element model to construct two adjacent foundation raft models includes selecting two adjacent warehouse sections with the largest areas, namely warehouse A1 and warehouse A2, and modeling them using the Midas Gen finite element model. The two foundation rafts are both 40x40x0.3 m according to the conditions.

[0022] Furthermore, the skip-bin method casting simulation and analysis and calculation are performed on the two adjacent concrete bottom models, including first casting the A1 bin section, and then casting the A2 bin section after an interval of no less than 7 days. According to the progress of the construction site, the average temperature is 19-27°C, the ambient temperature is 23°C, there are no constrained boundary conditions around the bin area, and the sides are fully constrained boundary conditions.

[0023] Furthermore, the skip-bin method casting simulation and analytical calculation are performed on the two adjacent concrete bottom models, including the requirement that the earliest closure time of the adjacent bins is 7 days, i.e. 168 hours, according to which the skip-bin method is used. Therefore, the calculation sequence is to first calculate the casting of bin A1, and then calculate the casting of bin A2 7 days later, with a total calculation time of 500 hours.

[0024] Furthermore, the skip-bin method casting simulation and analytical calculation of the two adjacent concrete bottom models also includes selecting the A1 and A2 bin bottom plate section positions and node numbers respectively, observing the rising trend of the concrete temperature of the foundation bottom plate and its subsequent development trend as the cement continuously releases heat through hydration after the concrete is poured, and calculating the tensile stress value at the same time.

[0025] In a second aspect, the present invention provides a real-time temperature analysis simulation system using a skip bin method, which adopts the following technical solution:

[0026] A real-time temperature analysis simulation system using a skip bin method, comprising:

[0027] A monitoring device, an input instrument, a receiving device and an analyzing device, wherein the monitoring device is used to obtain monitoring data, and the monitoring data is input into the receiving device through the input instrument, and the data is analyzed by the analyzing device.

[0028] Furthermore, the monitoring device includes a temperature and humidity sensor and a temperature monitor, which are used to measure the ambient temperature and humidity and the concrete temperature, and transmit the measured data to a receiving device.

[0029] In summary, the present invention has the following beneficial technical effects:

[0030] Through the above scheme, the present invention obtains the pouring concrete strength grade, impermeability grade, amount of each material per cubic meter (cement, sand, gravel, water, admixture, additive), bin sequence information, pouring time information, pouring sequence information, demolding time, curing time and other numbers of concrete based on the skip-bin method, and obtains the thermal boundary conditions of the concrete in each bin more accurately based on these data. Then, based on the thermal boundary conditions, the temperature field of the concrete in all bins of the building is obtained by simulation analysis, which solves the problem in the prior art that the temperature field analysis of concrete pouring in separate bins is difficult due to the complex thermal boundary conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the variation of tensile strength with age according to an embodiment of the present invention.

[0032] Figure 2 Schematic diagram of defining the elastic modulus of concrete according to an embodiment of the present invention.

[0033] Figure 3 It is a schematic diagram of defining shrinkage and creep according to an embodiment of the present invention.

[0034] Figure 4 Schematic diagram of a finite element model of an embodiment of the present invention.

[0035] Figure 5 It is a schematic diagram of the cross-sectional position and node number of the A1 warehouse according to an embodiment of the present invention.

[0036] Figure 6 Schematic diagram of the temperature time history curve of the A1 chamber according to an embodiment of the present invention.

[0037] Figure 7 Schematic diagram of the stress time history curve of the A1 bin according to an embodiment of the present invention.

[0038] Figure 8 Schematic diagram of the time history curve of the tensile stress ratio of the A1 bin according to an embodiment of the present invention.

[0039] Fig. 9 It is a schematic diagram of the cross-sectional position and node number of the A2 warehouse according to an embodiment of the present invention.

[0040] Fig.10 Schematic diagram of the temperature time history curve of the A2 chamber according to an embodiment of the present invention.

[0041] Fig.11 Schematic diagram of the stress time history curve of the A2 bin according to an embodiment of the present invention.

[0042] Fig.12 Schematic diagram of the time history curve of the tensile stress ratio of the A2 bin according to an embodiment of the present invention.

[0043] Fig.13 This is a diagram of a real-time temperature analysis simulation system using a skip bin method according to an embodiment of the present invention.

[0044] Among them, 1. Temperature and humidity sensor; 2. Temperature monitor. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0046] Example 1

[0047] Reference Figure 1 A real-time temperature analysis simulation method using a skip bin method according to this embodiment includes:

[0048] Obtain foundation raft composition data and relevant construction specifications;

[0049] Calculate the variation trend of concrete tensile strength based on the obtained foundation raft composition data;

[0050] According to the relevant construction specifications of the foundation raft composition data, the relationship between the elastic modulus of concrete and time is calculated;

[0051] The Midas Gen finite element model was used to construct two adjacent foundation raft models;

[0052] The skip-bin method pouring simulation and analysis calculation were carried out on two adjacent concrete bottom models;

[0053] Get the analysis results.

[0054] Specifically,

[0055] This example is a construction project of a parking lot and ancillary supporting facilities in a central square. The project is an underground parking garage with 2 floors underground and 1 floor above ground, covering an area of ​​15399.35m 2 , building area 27796.6m 2 . It is currently in the foundation construction stage.

[0056] The foundation of this project is high-pressure jet enlarged head anchor rod-flat raft (column pier), and the main body is a frame structure. The main column grid size is mostly 8.1m. The maximum span of the beam is 8.1m.

[0057] The underground garage of this project is a frame structure, designed with two underground floors and one partial ground floor. The underground garage is about 81m long from east to west and about 184m long from north to south; the relative elevation of the top of the raft concrete structure of the underground garage is -10.000m, the top elevation of the second underground floor is -6.150m, and the top elevation of the first underground floor is -2.100m. The concrete grade of the foundation slab is C30, the thickness is 900mm, the length is 184m, and the width is 80m, which is an ultra-long concrete structure.

[0058] In the original design of this project, in order to control the temperature shrinkage and drying shrinkage cracks of concrete, the post-casting belt measure was adopted. In order to avoid cracking of the raft foundation and improve construction efficiency, this project adopts the "skip warehouse method" construction technology instead of leaving the post-casting belt.

[0059] 1. Material parameters and calculation basis

[0060] The foundation slab uses C30 commercial concrete. According to the "Concrete Mix Ratio Test Report" provided by the manufacturer, the concrete mix ratio is shown in Table 3-1. The relevant thermodynamics for the calculation of hydration heat during the foundation slab construction phase refer to the "Concrete Structure Design Code" and "Massive Concrete Construction Code", and the parameters are detailed in Table 3-2.

[0061] Table 3-1 Foundation raft composition

[0062]

[0063] Table 3-2 Thermodynamic parameters of base plate and foundation

[0064]

[0065] The formula for the adiabatic temperature rise of concrete is calculated based on the "Standard for Construction of Large Volume Concrete" (GB50496-2018).

[0066] The change of concrete elastic modulus and strength over time is calculated according to Appendix B of the "Standard for Construction of Mass Concrete" (GB50496-2018). The change trend of concrete tensile strength can be calculated as follows:

[0067] f tk (t) = f tk (1-e -γt ) (1)

[0068] Where: f tk (t) is the standard value of tensile strength at age t; f tk is the standard value of tensile strength of concrete, which is taken according to Table 3.3; γ is the coefficient which can be taken as 0.3. The tensile strength is defined in Midas Gen. Figure 1 .

[0069] Table 3.3 Standard values ​​of concrete tensile strength (N / mm 2 )

[0070]

[0071] According to the mass concrete specification, the relationship between the elastic modulus of concrete and time is determined:

[0072]

[0073] β=β 1 ×β 2 (3)

[0074] Where: E(t) is the elastic modulus at age t; E 0 It is the elastic modulus of concrete after 28 days of curing, and the value can be taken according to Table 5; is the coefficient, which can be taken as 0.09; β is the correction coefficient of the elastic modulus of the admixture in the concrete, which can be taken according to Table 3.5. The elastic modulus is defined in MidasGen. Figure 2 .

[0075] Table 3.4 Elastic modulus of concrete at 28 days under standard curing conditions

[0076] Concrete strength grade <![CDATA[Elastic modulus of concrete (N / mm 2 )]]> C30 <![CDATA[3.0×10 4 ]]>

[0077] Table 3.5 Correction coefficients for different admixture amounts

[0078] Dosage 0 20％ 30％ 40％ <![CDATA[Fly ash (β 1 )]]> 1 0.99 0.98 0.96 <![CDATA[Ground granulated blast-furnace slag ash (β 2 )]]> 1 1.02 1.03 1.04

[0079] In addition to defining its thermodynamic parameters, it is also necessary to consider its shrinkage and creep processes, see Figure 3(a) and Figure 3 (b) in .

[0080] 2. Midas Gen finite element model

[0081] The two adjacent warehouse sections with the largest area (A1 warehouse and A2 warehouse, with a plate thickness of 300mm) were selected for analysis and calculation. According to the construction organization plan, the A1 warehouse section was cast first, and the A2 warehouse section was cast after an interval of no less than 7 days.

[0082] The calculation model of the raft foundation of the two-storehouse garage is established. Figure 4 The two foundation rafts are both 40x40x0.3 m according to the conditions. According to the progress of the construction site, the average temperature in September and October in a certain place is 19-27℃, and the ambient temperature is 23℃. There are no constraint boundary conditions around the warehouse area, and the side is a fully constrained boundary condition.

[0083] The skip-bin method requires that the earliest closure time of adjacent bins is 7 days (168 hours). Therefore, the calculation sequence is: first calculate the pouring of bin A1, and then calculate the pouring of bin A2 7 days later. The total calculation time is 500 hours.

[0084] 4. Analysis of calculation results

[0085] 1. The first stage is pouring the A1 warehouse floor:

[0086] The selected A1 warehouse bottom plate section position and node number are shown in Figure 5 .Depend on Figure 6 It can be seen that after the concrete is poured, as the cement continues to hydrate and release heat, the concrete temperature of the foundation slab shows a clear upward trend, with the highest temperature reaching 26.7°C. Subsequently, as the cement hydration reaction weakens and the heat release decreases, the temperature begins to decrease and gradually approaches the ambient temperature. During the calculation period, the temperature difference between the internal nodes and the surface nodes is always controlled within 25°C, which meets the requirements of the specification and has a low risk of concrete cracking.

[0087] Depend on Figure 7 It can be seen that the maximum tensile stress of concrete is 1.4MPa, which is much smaller than the standard value of concrete tensile strength 2.01Mpa. The tensile stress ratio of concrete is not less than 1.15, and the concrete does not crack. Figure 8 .

[0088] 2. The second stage is pouring the A2 warehouse bottom plate:

[0089] The selected A2 warehouse bottom plate section position and node number are shown in Fig. 9 .Depend on Fig.10It can be seen that after the concrete is poured, as the cement continues to hydrate and release heat, the concrete temperature of the foundation slab shows a clear upward trend, with the highest temperature reaching 9.5°C. Subsequently, as the cement hydration reaction weakens and the heat release decreases, the temperature begins to decrease and gradually approaches the ambient temperature. During the calculation period, the temperature difference between the internal nodes and the surface nodes is always controlled within 25°C, which meets the requirements of the specification, and the risk of concrete cracking is low.

[0090] Depend on Fig.11 It can be seen that the maximum tensile stress of concrete is 1.08MPa, which is much smaller than the standard value of concrete tensile strength 2.01Mpa. The tensile stress ratio of concrete is not less than 1.15, and the concrete does not crack. Fig.12 .

[0091] V. Conclusion

[0092] The concrete used in the bottom slab of this project is high in cement. After the concrete is poured, a lot of heat is generated inside the bottom slab due to the hydration reaction. After the skip-bin method is used, the interval between the pouring of A1 and A2 bins is at least 7 days, and the temperature stress is well released. The temperature difference between the internal nodes and the external surface nodes of the bottom slab is within 25°C during the calculation period, which meets the requirements of the specification, and the risk of bottom slab cracking is small. After the A2 bin is finally poured, the stress calculation can be met. The size and thickness of other bin sections are less than 40x40x0.9 m, which can meet the requirements of the skip-bin method.

[0093] It should also be noted that pouring is not allowed when the ambient temperature is higher than 23°C; the temperature of the concrete entering the mold should be controlled to be no more than 20°C during pouring; during the pouring process, special circumstances such as sudden cooling of the weather may occur, and insulation measures need to be taken to prevent the outer surface of the concrete from cooling down too quickly, resulting in excessive temperature difference between the inside and outside of the concrete and causing cracks.

[0094] Example 2

[0095] The difference between this embodiment and embodiment 1 is that this embodiment provides a real-time temperature analysis simulation system using a bin skipping method, including:

[0096] Monitoring device: It consists of a temperature and humidity sensor 1 and a temperature monitor 2. The temperature and humidity sensor is responsible for real-time measurement of the ambient temperature and humidity at the construction site, accurately capturing the dynamic changes in ambient temperature and humidity; the temperature monitor focuses on measuring the temperature of the concrete itself, obtaining temperature data of the concrete at different construction stages. These measurement data will be transmitted to the receiving device in a timely and accurate manner, providing first-hand information for subsequent analysis.

[0097] Input instrument: Its function is to input various key data into the system. These data come from a wide range of sources, including ambient temperature and humidity, concrete temperature data collected by monitoring devices, and C30 foundation raft composition data obtained from other channels (such as the amount of each material per cubic meter, including cement, sand, gravel, water, admixtures, admixtures, etc.) and related construction specification information (such as concrete structure design specifications, thermodynamic reference data for hydration heat calculation in large-volume concrete construction specifications, etc.). Input instruments ensure the integrity and accuracy of the data required for system operation.

[0098] Receiving device: As the data gathering center, the receiving device is responsible for receiving data collected from the monitoring device and various data input through the input instrument. It integrates and preliminarily processes these data to prepare for the in-depth analysis of the subsequent analysis device and ensure the smooth flow of data within the system.

[0099] Analysis device: This is the core part of the system, with built-in professional data analysis algorithms and models. It simulates the temperature change of concrete during the skip-bin construction process based on the data provided by the receiving device. Combined with the Midas Gen finite element model, the skip-bin pouring simulation analysis and calculation of two adjacent C30 foundation raft models are performed. The analysis device calculates the key parameters such as the concrete temperature rise trend and tensile stress value, and then evaluates the risk of concrete cracking, providing a scientific basis for construction decisions.

[0100] Working principle:

[0101] Data collection and input stage: The temperature and humidity sensors and temperature monitors in the monitoring device continuously and in real time monitor the temperature and humidity of the construction site environment and the temperature of the concrete, and transmit the monitored data to the receiving device. At the same time, the operator uses the input instrument to input the C30 foundation raft composition data and related construction specification information into the system, and these data are also transmitted to the receiving device.

[0102] Data processing and simulation analysis stage: After receiving the data, the receiving device organizes and preliminarily processes it, and then passes the processed data to the analysis device. The analysis device calculates the change trend of concrete tensile strength and the relationship between elastic modulus and time according to the input foundation raft composition data and the corresponding formula. Then, two adjacent C30 foundation raft models are constructed using the Midas Gen finite element model, and simulated pouring analysis is carried out according to the construction requirements of the skip bin method. In the simulation process, it is set to pour the A1 bin section first, and pour the A2 bin section after an interval of no less than 7 days. Combined with the temperature conditions of the construction site (such as the average temperature of 19-27℃, the ambient temperature is 23℃), boundary conditions (no constraint boundary conditions around the bin area, and full constraint boundary conditions on the side) and the earliest closure time of adjacent bins in the skip bin method is 7 days (168h), the temperature change trend and tensile stress value after concrete pouring are calculated.

[0103] Result output and application stage: After the analysis device completes the simulation analysis, it outputs detailed analysis results, including concrete temperature time history curve, stress time history curve, tensile stress ratio time history curve, etc. By analyzing these results, construction personnel and technicians can intuitively understand the temperature change law and stress state of concrete during the skip-bin construction process and evaluate the risk of concrete cracking. If the analysis results show a high risk of cracking, technicians can adjust the construction plan accordingly, such as optimizing the concrete mix ratio, adjusting the pouring time interval, strengthening maintenance measures, etc., so as to ensure the quality of concrete construction, effectively avoid the occurrence of concrete cracks, and ensure the safety and stability of the construction project.

[0104] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A real-time temperature analysis simulation method using a skip bin method, characterized in that: include: Obtain foundation raft composition data and relevant construction specifications; Calculate the variation trend of concrete tensile strength based on the obtained foundation raft composition data; According to the relevant construction specifications of the foundation raft composition data, the relationship between the elastic modulus of concrete and time is calculated; The Midas Gen finite element model was used to construct two adjacent foundation raft models; The skip-bin method pouring simulation and analysis calculation were carried out on two adjacent concrete bottom models; Get the analysis results.

2. The real-time temperature analysis simulation method of the skip bin method according to claim 1, characterized in that: The obtaining of foundation raft composition data and related construction specifications includes obtaining the concrete mix ratio according to the concrete mix ratio test results provided by the manufacturer, and obtaining the related thermodynamic reference for hydration heat calculation in the foundation slab construction stage based on the concrete structure design specification and the mass concrete construction specification.

3. The real-time temperature analysis simulation method of the skip bin method according to claim 2, characterized in that: The variation trend of the tensile strength of concrete is calculated based on the obtained foundation raft composition data, including using the mass concrete construction standard as a reference for the variation of the elastic modulus and strength of concrete over time. The variation trend of the tensile strength of concrete is expressed as: f tk (t)=f tk (1-e -γt ) Where: f tk (t) is the standard value of tensile strength at age t; f tk is the standard value of tensile strength of concrete, and γ is the coefficient taken as 0.

3.

4. The real-time temperature analysis simulation method of the skip bin method according to claim 3 is characterized in that: The calculation of the relationship between the elastic modulus of concrete and time according to the relevant construction specifications of the foundation raft composition data includes determining the relationship between the elastic modulus of concrete and time according to the mass concrete specification: β＝β1×β2 Where: E(t) is the elastic modulus at age t; E0 is the elastic modulus of concrete after 28 days of curing; is the coefficient, which is taken as 0.09; β is the correction coefficient of the elastic modulus of the admixture in concrete.

5. The real-time temperature analysis simulation method of the skip bin method according to claim 4, characterized in that: The Midas Gen finite element model is used to construct two adjacent foundation raft models, including selecting two adjacent warehouse sections with the largest areas, namely warehouse A1 and warehouse A2, and modeling them using the Midas Gen finite element model. The two foundation rafts are both 40x40x0.3 m according to the conditions.

6. The real-time temperature analysis simulation method of the skip bin method according to claim 5, characterized in that: The skip-bin method casting simulation and analysis and calculation of two adjacent concrete bottom models include first casting the A1 bin section, and then casting the A2 bin section after an interval of not less than 7 days. According to the progress of the construction site, the average temperature is 19-27°C, the ambient temperature is 23°C, there are no constrained boundary conditions around the bin area, and the sides are fully constrained boundary conditions.

7. The real-time temperature analysis simulation method of the skip bin method according to claim 6, characterized in that: The skip-bin method casting simulation and analysis and calculation of the two adjacent concrete bottom models include that according to the skip-bin method, the earliest closure time of the adjacent bins is 7 days, i.e. 168 hours. Therefore, the calculation sequence is to first calculate the casting of bin A1, and then calculate the casting of bin A2 after 7 days. The total calculation time is 500 hours.

8. The real-time temperature analysis simulation method of the skip bin method according to claim 7, characterized in that: The skip-bin method pouring simulation and analytical calculation of two adjacent concrete bottom models also includes selecting the cross-sectional positions and node numbers of the A1 and A2 bin bottom plates respectively, observing the rising trend of the concrete temperature of the foundation bottom plate and its subsequent development trend after the concrete pouring as the cement continuously releases heat through hydration, and calculating the tensile stress value at the same time.

9. A real-time temperature analysis simulation system using a skip bin method, characterized in that: include: A monitoring device, an input instrument, a receiving device and an analyzing device, wherein the monitoring device is used to obtain monitoring data, and the monitoring data is input into the receiving device through the input instrument, and the data is analyzed by the analyzing device.

10. A real-time temperature analysis simulation system using a skip bin method according to claim 9, characterized in that: The monitoring device includes a temperature and humidity sensor and a temperature monitor, which are used to measure the ambient temperature and humidity and the concrete temperature, and transmit the measured data to a receiving device.

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