High-speed railway tunnel construction process carbon footprint intelligent monitoring and management method based on BIM

Abstract

The invention relates to the technical field of railway construction carbon monitoring, in particular to a BIM-based high-speed railway tunnel construction process carbon footprint intelligent monitoring and management method, which comprises the following steps: obtaining construction data of a high-speed railway tunnel construction process, and introducing an LCA carbon emission database into a BIM model to construct a BIM-LCA model; the method comprises the following steps: dividing a high-speed railway construction area into an external area, a tunnel entrance area and a tunnel interior area, and constructing an external-entrance-tunnel carbon emission diffusion equation based on a BIM-LCA model in combination with a Rayleigh-Taylor instability principle; solving a carbon concentration gradient between the tunnel entrance and the interior of the tunnel; and judging whether a carbon emission accumulation phenomenon exists in the current tunnel by using a Rayleigh-Taylor instability principle. The BIM-based intelligent carbon footprint monitoring and management method for the high-speed railway tunnel construction process is used for dynamically monitoring the carbon concentration gradient inside and outside a tunnel in real time, judging whether carbon emission is accumulated or flows backwards or not, and optimizing a construction strategy inside and outside the tunnel in advance.

Description

Technical Field

[0001] The present invention relates to the technical field of railway construction carbon monitoring, and in particular to a BIM-based carbon footprint intelligent monitoring and management method for a high-speed railway tunnel construction process. Background Art

[0002] The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of high-speed railway tunnels aims to accurately monitor the dynamic diffusion of carbon emissions during the construction process and optimize the construction scheduling strategies inside and outside the tunnel in real time. By constructing the external-entrance-tunnel carbon emission diffusion equation and combining the Rayleigh-Taylor instability principle to analyze the carbon emission concentration gradient, the accumulation of carbon emissions inside the tunnel can be controlled to prevent carbon emissions from being retained due to restricted air flow. This can realize intelligent monitoring of carbon footprints between construction areas, dynamically optimize construction scheduling, and improve the safety of tunnel construction and the efficiency of carbon emission management.

[0003] The existing intelligent monitoring of carbon footprint in the construction process of high-speed railway tunnels is usually difficult to accurately assess the diffusion path and accumulation trend of carbon emissions inside and outside the tunnel. In addition, factors such as limited air circulation inside the tunnel, backflow of carbon emissions from external construction, and uneven regional emissions will cause the carbon dioxide concentration inside the tunnel to remain at a high level for a long time, the oxygen content will decrease, and the risk of hypoxia for construction workers will increase. The high energy consumption operation of construction equipment will further aggravate the accumulation of carbon emissions and affect the safety of the construction environment. Therefore, a BIM-based intelligent monitoring and management method for carbon footprint in the construction process of high-speed railway tunnels is provided. Summary of the invention

[0004] The purpose of the present invention is to provide a BIM-based intelligent monitoring and management method for the carbon footprint of a high-speed railway tunnel construction process, so as to solve the problem raised in the above background technology that due to limited air circulation inside the tunnel, possible backflow of carbon emissions from external construction, and uneven emission rates in different construction areas, the carbon dioxide concentration inside the tunnel will be at a high level for a long time, the oxygen content will decrease, and the risk of hypoxia for construction workers will increase. The high energy consumption operation of construction equipment will further aggravate the accumulation of carbon emissions and affect the safety of the construction environment.

[0005] To achieve the above object, the present invention aims to provide a BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel, comprising the following steps: S1. Use sensors to obtain real-time construction data of the high-speed railway tunnel construction process, introduce the LCA carbon emission database into the BIM model to build a BIM-LCA model; S2. Divide the high-speed railway construction area into the external area, the tunnel entrance area and the tunnel internal area, and construct the external-entrance-tunnel carbon emission diffusion equation based on the BIM-LCA model combined with the Rayleigh-Taylor instability principle; The external-inlet-tunnel carbon emission diffusion equation is used to describe the carbon concentration variation trend and the carbon emission diffusion path; S3, based on the external-entrance-tunnel carbon emission diffusion equation, solve the carbon concentration gradient between the tunnel entrance and the tunnel interior, and monitor the carbon footprint inside and outside the tunnel in real time; S4. Based on the carbon concentration gradient at the internal interface of the tunnel entrance, the Rayleigh-Taylor instability principle is used to determine whether there is carbon emission accumulation in the tunnel, and dynamically optimize the construction strategies inside and outside the tunnel.

[0006] As a further improvement of the technical solution, the construction data includes carbon dioxide concentration, oxygen concentration, air flow rate, temperature, humidity, atmospheric pressure, fuel consumption rate of construction equipment, operating power of construction equipment, material transportation volume and material carbon emission factor; The BIM-LCA model associates carbon emission factors with construction activities to calculate total construction carbon emissions and construction carbon emission rates.

[0007] As a further improvement of the technical solution, the external-entrance-tunnel carbon emission diffusion equation is a diffusion equation constructed based on the BIM-LCA model and the Rayleigh-Taylor instability principle using real-time construction data of different areas of high-speed railway construction, which is used to describe the carbon concentration change trend and carbon emission diffusion path between construction areas; In S2, the high-speed railway construction area is divided into an external area, a tunnel entrance area and a tunnel internal area. Based on the BIM-LCA model and the Rayleigh-Taylor instability principle, an external-entrance-tunnel carbon emission diffusion equation is constructed. The specific method steps are as follows: S2.1. Divide the high-speed railway construction area into three construction monitoring areas, including the external area , Tunnel entrance area and the inner area of ​​the tunnel , and collect construction data of these three construction monitoring areas respectively; S2.2. Based on the construction data of the three construction monitoring areas, the BIM-LCA model is combined with the Rayleigh-Taylor turbulent diffusion equation to construct the external-entrance-tunnel carbon emission diffusion equation.

[0008] As a further improvement of this technical solution, in S2.2, based on the construction data of the three construction monitoring areas, the BIM-LCA model is combined with the Rayleigh-Taylor turbulent diffusion equation to construct the external-entrance-tunnel carbon emission diffusion equation. The principle is as follows: S2.2.1. Introduce the factors affecting carbon emissions during the construction phase, such as carbon emission sources, air convection, and diffusion, into the basic formula of carbon concentration based on the mass conservation theorem; S2.2.2, based on the construction data of the three construction monitoring areas, the basic formula of carbon concentration based on the mass conservation theorem is used to construct the external-entrance-tunnel carbon emission diffusion equation.

[0009] As a further improvement of the technical solution, the external-inlet-tunnel carbon emission diffusion equation is as follows: ; in, is the carbon concentration in the tunnel entrance area; For time; is the air velocity at the tunnel entrance; is the coordinate along the tunnel axis; is the carbon concentration in the external construction area; is the turbulent diffusion coefficient at the tunnel entrance; represents the carbon diffusion at the tunnel entrance; is the carbon emission influencing factor at the tunnel entrance; is the Rayleigh-Taylor turbulence influence coefficient at the tunnel entrance; is the air density at the tunnel entrance; is the outside air density; is the acceleration due to gravity; ; in, is the carbon concentration in the inner area of ​​the tunnel; is the air velocity inside the tunnel; is the turbulent diffusion coefficient inside the tunnel; Indicates the carbon diffusion inside the tunnel; is the influencing factor of carbon emission inside the tunnel; is the Rayleigh-Taylor turbulence influence coefficient inside the tunnel; is the air density inside the tunnel.

[0010] As a further improvement of the technical solution, in S3, the carbon concentration gradient between the tunnel entrance and the inside of the tunnel is solved based on the external-entrance-tunnel carbon emission diffusion equation, and the carbon footprint inside and outside the tunnel is monitored in real time. The specific method steps are as follows: S3.1. Solve the carbon emission rate at the tunnel entrance and inside based on the external-entrance-tunnel carbon emission diffusion equation, and monitor the carbon footprint inside and outside the tunnel in real time; S3.2. Define the carbon concentration gradient at the tunnel entrance and interior interface based on the tunnel entrance and interior carbon emission rates.

[0011] As a further improvement of the technical solution, in S3.1, the carbon emission rates at the tunnel entrance and inside are solved based on the external-entrance-tunnel carbon emission diffusion equation, and the carbon footprint inside and outside the tunnel is monitored in real time. The specific method is as follows: ; ; in, is the carbon emission rate at the tunnel entrance; is the carbon discharge rate inside the tunnel; is the cross-sectional area of ​​the tunnel entrance; is the cross-sectional area of ​​air circulation inside the tunnel; is the rate of change of carbon concentration at the tunnel entrance; is the rate of change of carbon concentration inside the tunnel.

[0012] As a further improvement of the technical solution, in S3.2, the carbon concentration gradient at the junction of the tunnel entrance and the interior is defined based on the tunnel entrance and the internal carbon emission rate, and the specific method is as follows: ; in, is the carbon concentration gradient at the internal interface of the tunnel entrance.

[0013] As a further improvement of the technical solution, in S4, based on the carbon concentration gradient at the internal boundary of the tunnel entrance, the Rayleigh-Taylor instability principle is used to determine whether there is carbon emission accumulation in the tunnel, and dynamically optimize the construction strategies inside and outside the tunnel. The specific method steps are as follows: S4.1. Based on the carbon concentration gradient at the internal boundary of the tunnel entrance, the second-order derivative of the carbon emission rate with height is calculated using the finite difference approximation method: ; in, is the carbon emission rate; is the height; is the second-order derivative of carbon emission rate with height; is the carbon concentration gradient at the interface between the tunnel entrance and the interior at the current moment; is the carbon concentration gradient at the interface between the tunnel entrance and the interior at the previous moment; for height changes; S4.2. Use the Rayleigh-Taylor instability principle to determine whether there is carbon emission accumulation in the tunnel: If satisfied , then the carbon concentration gradient at the junction of the tunnel entrance and the interior is large, there may be carbon emissions accumulation inside the tunnel, and it is necessary to optimize the construction strategies inside and outside the tunnel; If not satisfied , then the carbon concentration difference inside and outside the tunnel is small, and the carbon footprint inside and outside the tunnel continues to be monitored in real time; in, is the acceleration due to gravity, is the air density inside the tunnel, is the air density at the tunnel entrance.

[0014] As a further improvement of this technical solution, the optimization strategy for the construction inside and outside the tunnel is as follows: In satisfying When the carbon concentration gradient at the internal interface of the tunnel entrance is large, the following measures are taken: reduce the operating time of high-carbon emission equipment in the tunnel, immediately evacuate employees in the tunnel, and add mechanical fans to improve air flow in the tunnel.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. In this BIM-based intelligent monitoring and management method for carbon footprint in the construction process of high-speed railway tunnels, based on the external-entrance-tunnel carbon emission diffusion equation and the Rayleigh-Taylor instability principle, the carbon concentration gradient inside and outside the tunnel can be dynamically monitored in real time to determine whether carbon emissions accumulate or backflow, and the carbon emission diffusion trend in the construction environment can be predicted in advance to avoid the risk of carbon gas accumulation due to restricted air flow.

[0016] 2. In the BIM-based intelligent monitoring and management method of carbon footprint in the construction process of high-speed railway tunnels, a BIM-LCA model is constructed and combined with the Rayleigh-Taylor instability principle to determine the diffusion of carbon emissions. When the risk of carbon emission accumulation is high, the construction progress is intelligently adjusted to optimize the time ratio between tunnel and external construction and reduce the backflow of carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a flow chart of the overall method of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See also Figure 1 As shown, this embodiment provides a BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel, comprising the following steps: S1. Use sensors to obtain real-time construction data of the high-speed railway tunnel construction process, introduce the LCA carbon emission database into the BIM model to build a BIM-LCA model; Specifically, the sensor includes at least: A carbon dioxide concentration sensor, preferably a non-dispersive infrared (NDIR) sensor, monitors the carbon dioxide concentration inside and outside the tunnel; Oxygen concentration sensor, using electrochemical sensor or optical sensor to detect the oxygen content in the environment in real time; Air velocity sensor, using a thermal anemometer or ultrasonic anemometer, is used to measure air velocity; Temperature and humidity sensor, preferably an integrated temperature and humidity sensor (such as DHT22) to monitor the temperature and humidity of the construction area; Atmospheric pressure sensor, using piezoresistive or capacitive pressure sensor to record ambient atmospheric pressure; In addition, carbon dioxide, oxygen, temperature and humidity sensors need to be evenly distributed at the tunnel entrance, inside and outside areas to cover key monitoring points.

[0020] In this embodiment, the construction data includes carbon dioxide concentration, oxygen concentration, air flow rate, temperature, humidity, atmospheric pressure, fuel consumption rate of construction equipment, operating power of construction equipment, material transportation volume and material carbon emission factor; The LCA carbon emission database is a life cycle assessment carbon emission database, which is a data set used to quantify the carbon emissions of products or projects throughout their life cycle. It mainly covers carbon emission factors from raw material acquisition, production, transportation, construction, use, maintenance, demolition to final waste treatment. In high-speed railway construction, the LCA carbon emission database contains the following data: building material carbon emission factors, energy consumption carbon emission factors, energy consumption carbon emission factors, construction process carbon emission factors, equipment operation carbon emission factors, and closed environment carbon diffusion data, etc.; The role of the LCA carbon emission database is: during the construction process, the sources of carbon emissions are complex (mechanical operation, material consumption, transportation, etc.), and the LCA carbon emission database can provide corresponding carbon emission factors for each construction activity, which is convenient for calculating and evaluating carbon footprints; through the LCA carbon emission database, the carbon emissions of different construction plans can be compared, and a lower-carbon construction path can be selected; combined with the LCA carbon emission database, it can be used to meet national or industry carbon emission standards, such as green buildings, to calculate and report carbon emissions; The BIM model is a digital platform for building and infrastructure construction management, which is used to store, calculate, visualize and analyze engineering information. The LCA carbon emission database can be combined with the BIM model to form a BIM-LCA model, thereby realizing real-time, visual and efficient carbon emission monitoring and optimization, as follows: BIM provides construction details including building materials, construction equipment, engineering stages, machinery operation time, energy consumption, construction progress and other information can be stored in the BIM model; the LCA carbon emission database provides carbon emission factors: through the material consumption, equipment operation time and transportation data recorded by the BIM model, the corresponding carbon emission factors can be found in the LCA carbon emission database to calculate the carbon emissions of the entire construction process; The BIM-LCA model associates carbon emission factors with construction activities to calculate total construction carbon emissions and construction carbon emission rates.

[0021] In this embodiment, the purpose of obtaining construction data is to provide dynamic input for LCA full life cycle carbon emission accounting. The construction stage is a high-carbon emission link in high-speed railway construction, and traditional LCA methods are usually based on static data, which makes it difficult to reflect carbon emission changes during the construction process in real time; it is also used to solve the external-entrance-tunnel carbon emission diffusion equation to calculate important data parameters such as the carbon concentration gradient inside and outside the tunnel.

[0022] In this embodiment, BIM technology is a digital modeling method used to create and manage building information during the design, construction and operation stages of building and infrastructure projects; a BIM model of the high-speed railway tunnel construction process is established, which not only contains geometric information in the engineering design stage, but also covers dynamic information such as construction progress and resource allocation; using the parametric characteristics of the BIM model, various activities in the construction process can be associated with carbon emission factors; for example, the energy consumption of different construction machinery, the distance and method of material transportation, and the specific operations of on-site construction can all be quantitatively analyzed through the BIM model; in addition, using the visualization function of the BIM model, carbon emission data can be intuitively displayed in the form of charts, three-dimensional models, etc., to help managers more intuitively understand the carbon emissions during the construction process; The LCA carbon emission database is a method for evaluating the environmental impact of products or processes. The BIM model is combined with the LCA carbon emission database to construct a BIM-LCA model, which is used to monitor carbon emissions during the construction process in real time.

[0023] S2. Divide the high-speed railway construction area into the external area, the tunnel entrance area and the tunnel internal area, and construct the external-entrance-tunnel carbon emission diffusion equation based on the BIM-LCA model combined with the Rayleigh-Taylor instability principle; The external-entrance-tunnel carbon emission diffusion equation is a diffusion equation constructed based on the BIM-LCA model and the Rayleigh-Taylor instability principle using real-time construction data from different areas of high-speed railway construction, and is used to describe the carbon concentration change trend and carbon emission diffusion path between construction areas; In this embodiment S2, the high-speed railway construction area is divided into an external area, a tunnel entrance area and a tunnel internal area. Based on the BIM-LCA model combined with the Rayleigh-Taylor instability principle, an external-entrance-tunnel carbon emission diffusion equation is constructed. The specific method steps are as follows: S2.1. Divide the high-speed railway construction area into three construction monitoring areas, including the external area , Tunnel entrance area and the inner area of ​​the tunnel , and collect construction data of these three construction monitoring areas respectively; S2.2. Based on the construction data of the three construction monitoring areas, the BIM-LCA model is combined with the Rayleigh-Taylor turbulent diffusion equation to construct the external-entrance-tunnel carbon emission diffusion equation.

[0024] In S2.2, based on the construction data of the three construction monitoring areas, the BIM-LCA model is combined with the Rayleigh-Taylor turbulent diffusion equation to construct the external-entrance-tunnel carbon emission diffusion equation. The principle is as follows: S2.2.1. The factors affecting carbon emission sources, air convection and diffusion on carbon emissions during the construction phase are introduced into the basic formula of carbon concentration based on the mass conservation theorem. The basic formula of carbon concentration based on the mass conservation theorem is as follows: ; Among them, the basic formula If the air flow in the construction environment affects the transmission of carbon emissions, the convection term is used to describe it; Said The diffusion of carbon gas in the construction area is affected by air turbulence, which can be described by Fick's second law. ; Said The carbon concentration change is affected by the emission of construction equipment and dilution of external air, and is described by the carbon emission factor term; Said The influence of air density changes inside and outside the tunnel on carbon diffusion is newly considered, and the Rayleigh-Taylor term is introduced as ; In this embodiment, the Rayleigh-Taylor turbulent diffusion equation is an equation form constructed based on the Rayleigh-Taylor instability principle. The Rayleigh-Taylor turbulent diffusion equation is the same as the Rayleigh-Taylor instability principle and is expressed as the same meaning and usage in this embodiment; Fick's second law describes the time evolution diffusion behavior of carbon gas in the construction environment and is used to calculate the dynamic changes of carbon concentration; The principle of combining the Rayleigh-Taylor turbulent diffusion equation with the BIM-LCA model is as follows: In carbon emission monitoring, BIM provides construction process data including construction machinery emissions, fuel consumption, construction progress and equipment operation status; LCA provides carbon footprint calculation including carbon emission factors of different materials and equipment, total carbon emissions and dynamic changes, and distribution of carbon emission sources during construction; however, the BIM-LCA model cannot describe how carbon emissions diffuse or accumulate in space, so the Rayleigh-Taylor turbulent diffusion equation is introduced to describe the spatial distribution and evolution of carbon emissions in the construction environment; The Rayleigh-Taylor instability principle describes that when a high-density fluid is located above a low-density fluid, due to the effect of gravity, an unstable perturbation will occur at the interface, resulting in fluid mixing and turbulent diffusion. In the tunnel construction environment: the high-concentration carbon dioxide inside the tunnel is regarded as a high-density fluid, and the low-concentration carbon dioxide at the tunnel entrance or the outside air is regarded as a low-density fluid. The external driving force is gravity and air velocity; If the difference in air density between inside and outside the tunnel is large, carbon emissions may be retained inside the tunnel and difficult to diffuse to the outside, forming a "carbon emission accumulation" phenomenon, affecting construction safety; S2.2.2, based on the construction data of the three construction monitoring areas, the basic formula of carbon concentration based on the mass conservation theorem is used to construct the external-entrance-tunnel carbon emission diffusion equation.

[0025] The external-inlet-tunnel carbon emission diffusion equation is as follows: ; in, is the carbon concentration in the tunnel entrance area; For time; is the air velocity at the tunnel entrance; is the coordinate along the tunnel axis; is the carbon concentration in the external construction area; is the turbulent diffusion coefficient at the tunnel entrance; represents the carbon diffusion at the tunnel entrance; is the carbon emission influencing factor at the tunnel entrance; is the Rayleigh-Taylor turbulence influence coefficient at the tunnel entrance, which is related to the fluid density difference and turbulence intensity at the tunnel entrance and is calibrated through experiments; is the air density at the tunnel entrance; is the outside air density; is the acceleration due to gravity; ; in, is the carbon concentration in the inner area of ​​the tunnel; is the air velocity inside the tunnel; is the turbulent diffusion coefficient inside the tunnel; Indicates the carbon diffusion inside the tunnel; is the influencing factor of carbon emission inside the tunnel; is the Rayleigh-Taylor turbulence influence coefficient inside the tunnel, which is related to the fluid density difference and turbulence intensity inside the tunnel and is calibrated through experiments; is the air density inside the tunnel. , Calculated from the carbon emission source intensity in the BIM-LCA model.

[0026] In this example, the changes in carbon emission concentration in different areas are affected by: construction equipment emissions (determined by the LCA carbon emission factor), air flow (wind speed in the construction environment), diffusion effects (controlled by the turbulent diffusion coefficient), and environmental factors; The external-entrance-tunnel carbon emission diffusion equation integrates BIM-LCA carbon emission modeling, turbulent diffusion and Rayleigh-Taylor turbulent diffusion equation to monitor the carbon emissions of the construction environment in real time and provide a theoretical basis for optimizing construction scheduling.

[0027] S3, based on the external-entrance-tunnel carbon emission diffusion equation, solve the carbon concentration gradient between the tunnel entrance and the tunnel interior, and monitor the carbon footprint inside and outside the tunnel in real time; In this embodiment S3, the carbon concentration gradient between the tunnel entrance and the tunnel interior is solved based on the external-entrance-tunnel carbon emission diffusion equation, and the carbon footprint inside and outside the tunnel is monitored in real time. The specific method steps are as follows: S3.1. Solve the carbon emission rate at the tunnel entrance and inside based on the external-entrance-tunnel carbon emission diffusion equation, and monitor the carbon footprint inside and outside the tunnel in real time; S3.2. Define the carbon concentration gradient at the tunnel entrance and interior interface based on the tunnel entrance and interior carbon emission rates.

[0028] In S3.1, based on the external-entrance-tunnel carbon emission diffusion equation, the carbon emission rates at the tunnel entrance and inside are solved to monitor the carbon footprint inside and outside the tunnel in real time. The specific method is as follows: ; ; in, is the carbon emission rate at the tunnel entrance; is the carbon discharge rate inside the tunnel; is the cross-sectional area of ​​the tunnel entrance; is the cross-sectional area of ​​air circulation inside the tunnel; is the rate of change of carbon concentration at the tunnel entrance; is the rate of change of carbon concentration inside the tunnel.

[0029] In this example, the carbon emission rate at the tunnel entrance is defined as In the formula, It represents the carbon emission flow rate at the tunnel entrance, which is determined by the air velocity. If the wind speed is high, the carbon emission is more likely to diffuse and flow out of the tunnel entrance area. is the diffusion effect of carbon concentration, which is determined by the turbulent diffusion coefficient and describes how carbon gas diffuses along the tunnel. If the carbon concentration gradient is large, the carbon diffusion is more intense. Indicates the impact of external construction on carbon emissions, taking into account the difference in carbon concentration between the tunnel entrance and the external construction area. If the carbon concentration at the tunnel entrance is higher than that in the external construction area, the carbon emission rate is reduced and carbon is likely to accumulate at the tunnel entrance; The effect of Rayleigh-Taylor instability on carbon emissions is the carbon turbulence phenomenon caused by the difference between the air density at the tunnel entrance and the outside air density. If the tunnel air is heavier, carbon emissions are easily deposited downward, which may lead to carbon emissions being retained at the tunnel entrance. In this embodiment, although it is possible to directly determine whether carbon gas is retained by calculating the gradient of the carbon concentration inside and outside the tunnel, the carbon emission rates at the defined tunnel entrance and inside are introduced and calculated based on the external-entrance-tunnel carbon emission diffusion equation, which can not only describe the flow characteristics of carbon gas, but also reflect the dynamic diffusion of carbon gas; carbon concentration is only an instantaneous state variable, which represents the carbon concentration at a certain point in the tunnel at a certain time, and the large carbon mass will sink to the bottom of the tunnel. The carbon concentration data obtained by the sensor cannot take the height of the tunnel into account. If sensors are needed to calculate the carbon concentration in various areas of the tunnel, a large number of sensors are required, and in construction management, real-time monitoring is only the first step, and predicting the trend of carbon emissions is the key step.

[0030] In S3.2, the carbon concentration gradient at the tunnel entrance and internal boundary is defined based on the tunnel entrance and internal carbon emission rates, and the specific method is as follows: ; in, is the carbon concentration gradient at the tunnel entrance and internal boundary, It is the axial length of the boundary area between the tunnel entrance and the interior, which is determined according to the design dimensions of the tunnel.

[0031] In this embodiment, the carbon concentration gradient does not use the carbon concentration directly, but is calculated based on the carbon emission rate at the tunnel entrance and inside. This is because the carbon emission rate more directly reflects the source, flow and diffusion of carbon emissions, and the carbon concentration is only a local measurement value and it is difficult to reflect the entire carbon flow trend.

[0032] S4. Based on the carbon concentration gradient at the internal interface of the tunnel entrance, the Rayleigh-Taylor instability principle is used to determine whether there is carbon emission accumulation in the tunnel, and dynamically optimize the construction strategies inside and outside the tunnel.

[0033] In this embodiment S4, based on the carbon concentration gradient at the internal boundary of the tunnel entrance, the Rayleigh-Taylor instability principle is used to determine whether there is carbon emission accumulation in the tunnel, and dynamically optimize the construction strategy inside and outside the tunnel. The specific method steps are as follows: S4.1. Based on the carbon concentration gradient at the internal boundary of the tunnel entrance, the second-order derivative of the carbon emission rate with height is calculated using the finite difference approximation method: ; in, is the carbon emission rate; is the height; is the second-order derivative of carbon emission rate with height; is the carbon concentration gradient at the interface between the tunnel entrance and the interior at the current moment; is the carbon concentration gradient at the interface between the tunnel entrance and the interior at the previous moment; for height changes; S4.2. Use the Rayleigh-Taylor instability principle to determine whether there is carbon emission accumulation in the tunnel: If satisfied , then the carbon concentration gradient at the junction of the tunnel entrance and the interior is large, there may be carbon emissions accumulation inside the tunnel, and it is necessary to optimize the construction strategies inside and outside the tunnel; If not satisfied , then the carbon concentration difference inside and outside the tunnel is small, and the carbon footprint inside and outside the tunnel continues to be monitored in real time; in, is the acceleration due to gravity, is the air density inside the tunnel, is the air density at the tunnel entrance.

[0034] In this example, the second derivative of the carbon emission rate with height is It describes how the carbon emission rate changes with altitude. If the change is drastic, it means that carbon emissions change drastically with altitude, which may lead to gas accumulation. If the change is small, it means that carbon emissions are relatively uniform and air flow is relatively stable. The Rayleigh-Taylor instability principle is used to determine whether carbon emissions are likely to accumulate: if , it means that carbon emissions change dramatically with height, which may cause turbulent accumulation, insufficient air flow, and difficulty in diffusing carbon gas, which may cause construction workers to lack oxygen or excessive carbon dioxide concentration. It is necessary to optimize the construction strategies inside and outside the tunnel to reduce the risk of carbon accumulation. If it is not met , it means that the carbon emissions are relatively uniform, the air fluidity is good, and the carbon gas can diffuse normally.

[0035] In this embodiment, the optimization strategy for tunnel internal and external construction is as follows: In satisfying When the carbon concentration gradient at the internal interface of the tunnel entrance is large, the following measures are taken: reduce the operating time of high-carbon emission equipment in the tunnel, immediately evacuate employees in the tunnel, and add mechanical fans to improve air flow in the tunnel.

[0036] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only preferred examples of the present invention, and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel, characterized in that: The following steps are involved: S1. Use sensors to obtain real-time construction data of the high-speed railway tunnel construction process, introduce the LCA carbon emission database into the BIM model to build a BIM-LCA model; S2. Divide the high-speed railway construction area into the external area, the tunnel entrance area and the tunnel internal area, and construct the external-entrance-tunnel carbon emission diffusion equation based on the BIM-LCA model combined with the Rayleigh-Taylor instability principle; The external-inlet-tunnel carbon emission diffusion equation is used to describe the carbon concentration variation trend and the carbon emission diffusion path; S3, based on the external-entrance-tunnel carbon emission diffusion equation, solve the carbon concentration gradient between the tunnel entrance and the tunnel interior, and monitor the carbon footprint inside and outside the tunnel in real time; S4. Based on the carbon concentration gradient at the internal interface of the tunnel entrance, the Rayleigh-Taylor instability principle is used to determine whether there is carbon emission accumulation in the tunnel, and dynamically optimize the construction strategies inside and outside the tunnel.

2. The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel according to claim 1 is characterized by: The construction data include carbon dioxide concentration, oxygen concentration, air flow rate, temperature, humidity, atmospheric pressure, fuel consumption rate of construction equipment, operating power of construction equipment, material transportation volume and material carbon emission factor; The BIM-LCA model associates carbon emission factors with construction activities to calculate total construction carbon emissions and construction carbon emission rates.

3. The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel according to claim 2 is characterized by: The external-entrance-tunnel carbon emission diffusion equation is a diffusion equation constructed based on the BIM-LCA model and the Rayleigh-Taylor instability principle using real-time construction data from different areas of high-speed railway construction, and is used to describe the carbon concentration change trend and carbon emission diffusion path between construction areas; In S2, the high-speed railway construction area is divided into an external area, a tunnel entrance area and a tunnel internal area. Based on the BIM-LCA model and the Rayleigh-Taylor instability principle, an external-entrance-tunnel carbon emission diffusion equation is constructed. The specific method steps are as follows: S2.

1. Divide the high-speed railway construction area into three construction monitoring areas, including the external area , Tunnel entrance area and the inner area of ​​the tunnel , and collect construction data of these three construction monitoring areas respectively; S2.

2. Based on the construction data of the three construction monitoring areas, the BIM-LCA model is combined with the Rayleigh-Taylor turbulent diffusion equation to construct the external-entrance-tunnel carbon emission diffusion equation.

4. The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel according to claim 3 is characterized by: In S2.2, based on the construction data of the three construction monitoring areas, the BIM-LCA model is combined with the Rayleigh-Taylor turbulent diffusion equation to construct the external-entrance-tunnel carbon emission diffusion equation. The principle is as follows: S2.2.

1. Introduce the factors affecting carbon emissions during the construction phase, such as carbon emission sources, air convection, and diffusion, into the basic formula of carbon concentration based on the mass conservation theorem; S2.2.2, based on the construction data of the three construction monitoring areas, the basic formula of carbon concentration based on the mass conservation theorem is used to construct the external-entrance-tunnel carbon emission diffusion equation.

5. The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel according to claim 4 is characterized by: The external-inlet-tunnel carbon emission diffusion equation is as follows: ； in, is the carbon concentration in the tunnel entrance area; For time; is the air velocity at the tunnel entrance; is the coordinate along the tunnel axis; is the carbon concentration in the external construction area; is the turbulent diffusion coefficient at the tunnel entrance; represents the carbon diffusion at the tunnel entrance; is the carbon emission influencing factor at the tunnel entrance; is the Rayleigh-Taylor turbulence influence coefficient at the tunnel entrance; is the air density at the tunnel entrance; is the outside air density; is the acceleration due to gravity; ； in, is the carbon concentration in the inner area of ​​the tunnel; is the air velocity inside the tunnel; is the turbulent diffusion coefficient inside the tunnel; Indicates the carbon diffusion inside the tunnel; is the influencing factor of carbon emission inside the tunnel; is the Rayleigh-Taylor turbulence influence coefficient inside the tunnel; is the air density inside the tunnel.

6. The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel according to claim 5 is characterized by: In S3, the carbon concentration gradient between the tunnel entrance and the inside of the tunnel is solved based on the external-entrance-tunnel carbon emission diffusion equation, and the carbon footprint inside and outside the tunnel is monitored in real time. The specific method steps are as follows: S3.

1. Solve the carbon emission rate at the tunnel entrance and inside based on the external-entrance-tunnel carbon emission diffusion equation, and monitor the carbon footprint inside and outside the tunnel in real time; S3.

2. Define the carbon concentration gradient at the tunnel entrance and interior interface based on the tunnel entrance and interior carbon emission rates.

7. The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel according to claim 6 is characterized by: In S3.1, based on the external-entrance-tunnel carbon emission diffusion equation, the carbon emission rates at the tunnel entrance and inside are solved to monitor the carbon footprint inside and outside the tunnel in real time. The specific method is as follows: ； ； in, is the carbon emission rate at the tunnel entrance; is the carbon discharge rate inside the tunnel; is the cross-sectional area of ​​the tunnel entrance; is the cross-sectional area of ​​air circulation inside the tunnel; is the rate of change of carbon concentration at the tunnel entrance; is the rate of change of carbon concentration inside the tunnel.

8. The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel according to claim 7 is characterized by: In S3.2, the carbon concentration gradient at the tunnel entrance and internal boundary is defined based on the tunnel entrance and internal carbon emission rates, and the specific method is as follows: ； in, is the carbon concentration gradient at the internal interface of the tunnel entrance.

9. The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel according to claim 8 is characterized by: In S4, based on the carbon concentration gradient at the internal boundary of the tunnel entrance, the Rayleigh-Taylor instability principle is used to determine whether there is carbon emission accumulation in the tunnel, and dynamically optimize the construction strategies inside and outside the tunnel. The specific method steps are as follows: S4.

1. Based on the carbon concentration gradient at the internal boundary of the tunnel entrance, the second-order derivative of the carbon emission rate with height is calculated using the finite difference approximation method: ； in, is the carbon emission rate; is the height; is the second-order derivative of carbon emission rate with height; is the carbon concentration gradient at the interface between the tunnel entrance and the interior at the current moment; is the carbon concentration gradient at the interface between the tunnel entrance and the interior at the previous moment; for height changes; S4.

2. Use the Rayleigh-Taylor instability principle to determine whether there is carbon emission accumulation in the tunnel: If satisfied , then the carbon concentration gradient at the junction of the tunnel entrance and the interior is large, there may be carbon emissions accumulation inside the tunnel, and it is necessary to optimize the construction strategies inside and outside the tunnel; If not satisfied , the carbon concentration difference inside and outside the tunnel is small, and the carbon footprint inside and outside the tunnel continues to be monitored in real time; among them, is the acceleration due to gravity, is the air density inside the tunnel, is the air density at the tunnel entrance.

10. The BIM-based intelligent monitoring and management method for carbon footprint in the construction process of a high-speed railway tunnel according to claim 9 is characterized in that: The optimization strategy for tunnel internal and external construction is as follows: In satisfying When the carbon concentration gradient at the internal interface of the tunnel entrance is large, the following measures are taken: reduce the operating time of high-carbon emission equipment in the tunnel, immediately evacuate employees in the tunnel, and add mechanical fans to improve air flow in the tunnel.

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