Method and system for determining tunnel temperature comfort zone range considering altitude and ground temperature

Abstract

The application discloses a tunnel temperature comfort zone range determination method considering altitude and ground temperature, relates to the tunnel engineering blasting construction technical field, and comprises the following steps: obtaining design required air volume under different conditions and different altitudes according to model parameters, environment parameters and design specifications; obtaining required air pipe wind speed and air supply temperature under different altitudes according to model parameters, environment parameters, design required air volume under different conditions and different altitudes; obtaining tunnel temperature field changes when the ground temperature is constant and the altitude changes and when the altitude is constant and the ground temperature changes according to the required air pipe wind speed and the air supply temperature under different altitudes; and obtaining the tunnel temperature comfort zone range under arbitrary altitude and ground temperature according to the tunnel temperature field changes when the ground temperature is constant and the altitude changes and when the altitude is constant and the ground temperature changes. The application can determine the tunnel temperature comfort zone range in the tunnel construction ventilation blasting stage under the special environment of high altitude and high ground temperature.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering blasting construction technology, and in particular to a method and system for determining the temperature comfort zone range inside a tunnel, taking into account altitude and ground temperature. Background Technology

[0002] Drill-and-blast method, also known as drilling and blasting construction, refers to a construction method that uses explosives to break up rock masses and create tunnels. It is used in the vast majority of railway tunnel projects in China. The construction period of the drill-and-blast method mainly includes five steps: drilling at the tunnel face, charging and blasting (blasting stage), muck removal (muck removal stage), frame erection, and wet spraying. The tunnel face, also called the tunnel face, is a term in tunnel construction referring to the working face that continuously advances during tunnel excavation (in coal mining, mining, or tunnel engineering). The blasting and muck removal stages require ventilation to remove and dilute pollutants and dust from the tunnel and lower the air temperature. In general tunnel construction, the design expectations for the scope of construction procedures have yielded relatively mature conclusions through numerous practical engineering applications and theoretical studies.

[0003] Due to the unique environment and geological conditions along the Sichuan-Tibet Railway, many tunnels face ventilation challenges caused by high altitude, high ground temperature, and the influence of altitude and ground temperature. Increased altitude leads to decreased air pressure, decreased air density, increased ground temperature, and increased air viscosity. Both altitude and ground temperature alter the airflow characteristics within the tunnel.

[0004] Airflow dilutes pollutant concentrations and carries pollutants away. However, when tunnels in special environments are constructed using the drill-and-blast method, the airflow characteristics change, and the ventilation effect directly affects the working time of the blasting and muck removal stages. The longer the construction period, the higher the construction budget. Therefore, it is crucial to reasonably control and predict the comfort zone range inside the tunnel in special environments to shorten the construction ventilation time and to rationally design the scope of construction procedures.

[0005] Because blasting and muck removal processes are significantly affected by airflow characteristics, the construction ventilation phase includes both blasting and muck removal stages. Previously, the operation time for blasting and muck removal was determined by engineering factors such as tunnel cross-section, surrounding rock grade, and construction scope. However, in geothermal environments, it is also necessary to ensure that the air temperature inside the tunnel is controlled below the standard limit (28℃). Furthermore, considering the influence of altitude on airflow characteristics, predicting the comfort zone range under different altitudes and geothermal conditions is crucial for improving construction ventilation efficiency, shortening the construction period, and selecting appropriate surrounding rock cooling methods.

[0006] Current methods for predicting the comfort zone during ventilation in high-altitude tunnel construction rely primarily on engineering experience and are mostly applied to low-altitude tunnels. However, high-altitude tunnel construction faces numerous controllable factors, presenting significant challenges and risks, and its operating costs and safety issues are also relatively prominent. Therefore, determining the comfort zone range within the tunnel during the ventilation and blasting phase of construction under the unique conditions of high altitude and high ground temperature has become a pressing issue for those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a method and system for determining the temperature comfort zone range inside a tunnel, taking into account altitude and ground temperature. This method can determine the temperature comfort zone range inside a tunnel during the ventilation and blasting stage of tunnel construction under special conditions of high altitude and high ground temperature.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] A method for determining the comfortable temperature zone inside a tunnel, taking into account altitude and ground temperature, the method comprising:

[0010] Obtain the tunnel's model parameters, environmental parameters, and design specifications;

[0011] Based on the model parameters, environmental parameters, and design specifications, the design air volume requirements under different conditions and the design air volume requirements at different altitudes are obtained.

[0012] Based on the model parameters, the environmental parameters, the design air volume required under different conditions, and the design air volume required at different altitudes, the duct velocity required for ventilation and the supply air temperature at different altitudes are obtained.

[0013] Based on the required duct velocity for ventilation and the supply air temperature at different altitudes, the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature remains constant and the altitude remains constant.

[0014] Based on the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant, the range of comfortable temperature inside the tunnel at any altitude and ground temperature is obtained.

[0015] Optionally, obtaining the design air volume requirement under different conditions and the design air volume requirement at different altitudes based on the model parameters, the environmental parameters, and the design specifications specifically includes:

[0016] The design air volume requirements under different conditions are calculated based on the model parameters, environmental parameters, and design specifications. The design air volume requirements under different conditions include the calculated air volume for minimum wind speed, the calculated air volume for maximum number of workers, the calculated air volume for forced ventilation, and the calculated air volume for diluting internal combustion exhaust gases.

[0017] The design air volume at zero altitude is obtained based on the design air volume under the different conditions described above.

[0018] Based on the altitude correction factor and the design air volume required at zero altitude, the design air volume required at different altitudes is calculated.

[0019] Optionally, obtaining the duct velocity required for ventilation and the supply air temperature at different altitudes based on the model parameters, the environmental parameters, the design air volume requirements under different conditions, and the design air volume requirements at different altitudes specifically includes:

[0020] Based on the model parameters, the design air volume required under different conditions, and the design air volume required at different altitudes, calculate the duct velocity required for ventilation.

[0021] Calculate the air supply temperature at different altitudes based on the environmental parameters.

[0022] Optionally, the step of obtaining the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant, based on the duct velocity required for ventilation and the supply air temperature at different altitudes, specifically includes:

[0023] Based on the required duct velocity for ventilation and the supply air temperature at different altitudes, finite element analysis was used to obtain the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant.

[0024] Optionally, obtaining the comfortable temperature range inside the tunnel at any altitude and ground temperature based on the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the altitude remains constant and the ground temperature changes specifically includes:

[0025] Based on the change in temperature field inside the tunnel when the ground temperature remains constant and the altitude changes, a temperature calculation formula under altitude changes is obtained by data fitting.

[0026] Based on the changes in the temperature field inside the tunnel when the altitude remains constant and the ground temperature changes, a temperature calculation formula under ground temperature changes is obtained by data fitting.

[0027] Based on the temperature calculation formulas for altitude changes and ground temperature changes, the comfortable temperature range inside the tunnel at any altitude and ground temperature is calculated.

[0028] The present invention also provides the following solutions:

[0029] A system for determining the comfortable temperature zone range inside a tunnel, taking into account altitude and ground temperature, the system comprising:

[0030] The parameter and specification acquisition module is used to acquire the tunnel's model parameters, environmental parameters, and design specifications.

[0031] The module for obtaining the required air volume is used to obtain the required air volume under different conditions and the required air volume at different altitudes based on the model parameters, the environmental parameters and the design specifications.

[0032] The duct velocity and supply air temperature acquisition module is used to obtain the duct velocity and supply air temperature required for ventilation at different altitudes based on the model parameters, the environmental parameters, the design air volume required under different conditions, and the design air volume required at different altitudes.

[0033] The temperature field change module is used to obtain the temperature field change in the tunnel when the ground temperature remains constant and the temperature field change in the tunnel when the ground temperature remains constant, based on the duct wind speed required for ventilation and the air supply temperature at different altitudes.

[0034] The temperature comfort zone range acquisition module is used to obtain the temperature comfort zone range inside the tunnel at any altitude and ground temperature based on the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant.

[0035] Optionally, the design requires the air volume to be obtained module, which specifically includes:

[0036] The design air volume calculation unit under different conditions is used to calculate the design air volume under different conditions based on the model parameters, the environmental parameters and the design specifications; the design air volume under different conditions includes the calculated air volume for minimum wind speed, the calculated air volume for maximum number of workers, the calculated air volume for forced ventilation and the calculated air volume for diluting internal combustion exhaust gas;

[0037] A unit for obtaining the design air volume at zero altitude is used to obtain the design air volume at zero altitude based on the design air volume under the different conditions described above.

[0038] The design air volume calculation unit at different altitudes is used to calculate the design air volume at different altitudes based on the altitude correction coefficient and the design air volume at zero altitude.

[0039] Optionally, the module for obtaining the duct air velocity and supply air temperature specifically includes:

[0040] The duct velocity calculation unit is used to calculate the duct velocity required for ventilation based on the model parameters, the design air volume required under different conditions, and the design air volume required at different altitudes.

[0041] The air supply temperature calculation unit is used to calculate the air supply temperature at different altitudes based on the environmental parameters.

[0042] Optionally, the temperature field change obtaining module specifically includes:

[0043] The temperature field change unit is used to obtain the temperature field change in the tunnel when the ground temperature remains constant and the temperature field change in the tunnel when the ground temperature changes, based on the duct wind speed required for ventilation and the air supply temperature at different altitudes, using finite element analysis.

[0044] Optionally, the module for obtaining the temperature comfort zone range specifically includes:

[0045] The temperature calculation formula under altitude change is obtained by a unit, which is used to obtain the temperature calculation formula under altitude change by data fitting based on the change of temperature field in the tunnel when the ground temperature is constant and the altitude changes.

[0046] The temperature calculation formula under ground temperature change is obtained by a unit, which is used to obtain the temperature calculation formula under ground temperature change by data fitting based on the change of temperature field in the tunnel when the altitude is constant and the ground temperature changes.

[0047] The temperature comfort zone calculation unit is used to calculate the temperature comfort zone range inside the tunnel at any altitude and ground temperature based on the temperature calculation formula under altitude change and the temperature calculation formula under ground temperature change.

[0048] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0049] This invention discloses a method and system for determining the comfortable temperature zone range inside a tunnel, taking into account altitude and ground temperature. Specifically designed for the special environments of high altitude and high ground temperature, this method considers the influence of altitude and ground temperature on the comfortable temperature zone range inside the tunnel. It determines the comfortable temperature zone range inside the tunnel during the ventilation and blasting stage of tunnel construction under these special environments. By using model parameters, environmental parameters, and design specifications, the design air volume required under different conditions and at different altitudes is obtained. Based on these parameters, the duct velocity required for ventilation and the supply air temperature at different altitudes are also obtained. Furthermore, based on these duct velocity and supply air temperature, the changes in the tunnel temperature field when altitude changes while ground temperature remains constant, and the changes in the tunnel temperature field when ground temperature changes while altitude remains constant, are obtained. Finally, based on these changes in the tunnel temperature field when altitude changes while ground temperature remains constant, and the changes in the tunnel temperature field when ground temperature changes while altitude remains constant, the comfortable temperature zone range inside the tunnel at any altitude and ground temperature is obtained. This allows for the determination of the comfortable temperature zone range inside the tunnel during the ventilation and blasting stage of tunnel construction under the special environments of high altitude and high ground temperature. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 A flowchart illustrating an embodiment of the method for determining the comfortable temperature zone range inside a tunnel considering altitude and ground temperature according to the present invention;

[0052] Figure 2 A schematic diagram illustrating the implementation process of the method for determining the comfortable temperature zone range inside a tunnel, taking into account altitude and ground temperature, according to the present invention.

[0053] Figure 3 This is a schematic diagram of step 1-1 of the present invention;

[0054] Figure 4 This is a schematic diagram of steps 1-2 of the present invention;

[0055] Figure 5 This is a schematic diagram of steps 1-3 of the present invention;

[0056] Figure 6 This is a schematic diagram of the temperature change fitting curves at various monitoring points of TH0 in this invention;

[0057] Figure 7 This is a schematic diagram of steps 1-4 of the present invention;

[0058] Figure 8 This is a schematic diagram of the fitting curves for different geothermal temperature variations according to the present invention;

[0059] Figure 9 This is a structural diagram of an embodiment of the system for determining the comfortable temperature range inside a tunnel, taking into account altitude and ground temperature, according to the present invention. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] The purpose of this invention is to provide a method and system for determining the temperature comfort zone range inside a tunnel, taking into account altitude and ground temperature. This method can determine the temperature comfort zone range inside a tunnel during the ventilation and blasting stage of tunnel construction under special conditions of high altitude and high ground temperature.

[0062] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0063] Figure 1 This is a flowchart illustrating an embodiment of the method for determining the comfortable temperature zone inside a tunnel, taking into account altitude and ground temperature, according to the present invention. See also... Figure 1 The method for determining the comfortable temperature zone inside the tunnel, taking into account altitude and ground temperature, includes:

[0064] Step 101: Obtain the tunnel's model parameters, environmental parameters, and design specifications.

[0065] In step 101, the model parameters include the tunnel cross-sectional area, tunnel length, duct diameter, and distance from the duct inlet to the tunnel face; the environmental parameters include the annual average temperature, altitude, and ground temperature of the tunnel location; and the design specifications include the "Guiding Manual for Ventilation Technology and Standardized Management in Railway Tunnel Construction", "Railway Tunnel Construction Specifications" (TB10120-2002), and "Highway Tunnel Construction Technical Specifications".

[0066] Step 102: Based on the model parameters, environmental parameters, and design specifications, obtain the design air volume requirements under different conditions and at different altitudes.

[0067] Step 102 specifically includes:

[0068] The design air volume requirement is calculated based on model parameters, environmental parameters, and design specifications under different conditions. The design air volume requirement under different conditions includes the calculated air volume for minimum wind speed, the calculated air volume for the maximum number of workers, the calculated air volume for forced ventilation, and the calculated air volume for diluting internal combustion exhaust gases.

[0069] The design air volume at zero altitude is obtained based on the design air volume under different conditions.

[0070] Based on the altitude correction factor and the design air volume at zero altitude, calculate the design air volume at different altitudes.

[0071] Step 103: Based on the model parameters, environmental parameters, design air volume requirements under different conditions, and design air volume requirements at different altitudes, obtain the duct velocity required for ventilation and the supply air temperature at different altitudes.

[0072] Step 103 specifically includes:

[0073] Based on the model parameters, the required air volume under different conditions, and the required air volume at different altitudes, calculate the duct velocity required for ventilation.

[0074] Calculate the air supply temperature at different altitudes based on environmental parameters.

[0075] Step 104: Based on the duct wind speed required for ventilation and the supply air temperature at different altitudes, obtain the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature remains constant and the altitude remains constant.

[0076] Step 104 specifically includes:

[0077] Based on the required duct velocity for ventilation and the supply air temperature at different altitudes, finite element analysis was used to obtain the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant.

[0078] Step 105: Based on the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant, the range of the comfortable temperature zone inside the tunnel at any altitude and ground temperature is obtained.

[0079] Step 105 specifically includes:

[0080] Based on the change in temperature field inside the tunnel when the ground temperature remains constant and the altitude changes, a formula for calculating temperature under altitude changes is obtained by fitting data.

[0081] Based on the changes in the temperature field inside the tunnel when the altitude remains constant and the ground temperature changes, a temperature calculation formula under ground temperature changes is obtained by fitting the data.

[0082] Based on the temperature calculation formulas for altitude changes and ground temperature changes, the comfortable temperature range inside the tunnel at any altitude and ground temperature is calculated.

[0083] The technical solution of the present invention is illustrated below with a specific embodiment:

[0084] Figure 2 This is a schematic diagram illustrating the implementation process of the method for determining the comfortable temperature zone inside a tunnel, taking into account altitude and ground temperature, according to the present invention. See also... Figure 2 The present invention provides a method for determining the comfortable temperature zone inside a tunnel, taking into account altitude and ground temperature. The process is detailed below:

[0085] In step 1-1, the model parameters and environmental parameters of the tunnel are obtained, and the design air volume required under different conditions and at different altitudes is calculated based on the model parameters, environmental parameters and design specifications.

[0086] In this invention, the design specifications refer to the "Guiding Manual for Ventilation Technology and Standardized Management in Railway Tunnel Construction", "Railway Tunnel Construction Specifications" (TB10120-2002), and "Technical Specifications for Highway Tunnel Construction".

[0087] In this invention, the purpose of calculating the required air volume is to determine the duct velocity required for ventilation.

[0088] In steps 1-2, based on the tunnel model parameters, environmental parameters, and design air volume requirements, the required duct velocity and supply air temperature at different altitudes are determined.

[0089] In steps 1-3, the temperature calculation formula under altitude change is determined based on the change in temperature field inside the tunnel caused by altitude change.

[0090] In steps 1-4, the temperature calculation formula under the influence of ground temperature changes on the temperature field inside the tunnel is determined.

[0091] In steps 1-5, the temperature comfort zone range inside the tunnel is predicted based on the temperature calculation formula at any altitude and ground temperature.

[0092] Figure 3 A schematic diagram of step 1-1 is provided. See also... Figure 3 In step 1-1-1, the model parameters and environmental parameters of the tunnel are obtained.

[0093] This invention requires obtaining the following model parameters for the tunnel: tunnel cross-sectional area A (m²) 2 The tunnel length is L1 (m), the duct diameter is L2 (m), and the distance from the duct inlet to the tunnel face is L3 (m). The tunnel cross-sectional shape does not affect the calculation results, but the cross-sectional area will affect the required air volume calculation. The cross-sectional area A in the actual project can be substituted into the required air volume calculation formula in Table 1.

[0094] This invention requires obtaining environmental parameters: the annual average temperature, altitude, and ground temperature of the tunnel location.

[0095] In step 1-1-2, the required air volume for different situations is calculated according to the design specifications.

[0096] The required design air volume for different situations is calculated according to the "Guidance Manual for Ventilation Technology and Standardized Management in Railway Tunnel Construction", as shown in the table below:

[0097] Table 1 Calculation of different air volume requirements

[0098]

[0099]

[0100] In step 1-1-3, the design air volume at zero altitude was obtained.

[0101] This invention primarily targets smoke extraction during the blasting stage; therefore, the required air volume is designed to be Q = max(Q V Q P Q b If this method is applied to the slag removal stage, the required air volume is Q = max(Q V Q PQ b Q S ).

[0102] In step 1-1-4, the required air volume for the design at different altitudes is obtained.

[0103] The above values ​​represent the design air volume at zero altitude. The design air volume at different altitudes is calculated by multiplying the zero altitude air volume by the altitude correction factor K. γ get.

[0104]

[0105] In the formula: Z Z Altitude, in meters (m).

[0106] The purpose of calculating the required air volume for the design is to obtain the air velocity in the duct.

[0107] Figure 4 A schematic diagram of steps 1-2 is provided. See also... Figure 4 In step 1-2-1, the duct velocity is calculated.

[0108] The duct velocity is obtained by dividing the required design air volume by the cross-sectional area of ​​the duct.

[0109]

[0110] In the formula: V f Where is the duct velocity, m / s; Q is the design air volume, m³ / s. 3 / min; L2 is the duct diameter, m; L2 value is determined by actual construction design.

[0111] In step 1-2-2, the air supply temperature T0 at zero altitude is obtained.

[0112] To simplify calculations, the supply air temperature is based on the inlet air temperature T0 (the inlet air temperature T0 is the inlet air temperature at zero altitude; in practical applications, it is taken as the annual average temperature at the tunnel location), ignoring the warming effect of the fan and duct on the airflow.

[0113] In steps 1-2-3, the supply air temperature T at different altitudes is obtained. h .

[0114]

[0115] In the formula: T h The temperature at altitude H is given in °C; ΔH represents the temperature at altitude H and the temperature at altitude T0. h The difference in elevation between them, m; g t The temperature gradient is 0.5–0.7℃ / (100m).

[0116] Figure 5A schematic diagram of steps 1-3 is provided. See also... Figure 5 In step 1-3-1, finite element analysis is performed on the test conditions to obtain the influence of constant ground temperature and altitude change on the temperature field inside the tunnel.

[0117] In this embodiment, a standard double-track railway tunnel (also known as a double-track railway, which refers to a railway with two main lines within a certain mileage range, with separate up and down lines, and trains traveling in opposite directions running on different tracks) is selected as the cross-section, with a cross-sectional area of ​​82m². 2 The duct diameter is 1.8m. The physical model dimensions, duct layout location, and origin (0, 0, 0) position are as follows: Figure 6 As shown, the air duct inlet is 20m from the tunnel face. Table 2 shows the working conditions, which are the changes in the temperature field inside the tunnel when the surrounding rock temperature is constant at 40℃ and the altitude is 0km, 2km, 4km, and 6km. The air supply temperature is set according to the ambient temperature measured in the project, and is referenced from the Sichuan-Tibet Railway project. The excavation face temperature is the residual temperature of the tunnel face after the explosive explosion, which is 70℃ here.

[0118] Table 2 Test Conditions

[0119]

[0120]

[0121] The CFD (Computational Fluid Dynamics) numerical method was used to simulate the airflow changes and temperature field distribution within the tunnel under various transient conditions. Multiple monitoring points were selected along the longitudinal direction of the tunnel to monitor the temperature changes at each location during the transient development of the airflow.

[0122] In step 1-3-1, the temperature calculation formula under altitude changes is determined based on the fitting results of altitude and location data.

[0123] Figure 6 Temperature distribution curves within the tunnel under TH0 condition are presented. To qualitatively analyze the temperature changes within the tunnel after ventilation stabilizes, the temperature variation trend under TH0 condition is obtained by fitting temperature and location. Figure 6 The standard limit line with T=28℃ was marked, and the temperature field distribution law at different locations in the TH0 working condition tunnel can be obtained. The temperature change curve is divided into three stages. In the first stage, the temperature rise rate is relatively fast, and the comfortable range that meets the specifications is within the range of X<100m. In the range of 150≤X≤400m, the temperature rises slowly. After X>400m, the temperature rises rapidly, and the temperature recovers to 40℃ at X=585m. It was found that T and X in the tunnel have a cubic nonlinear relationship.

[0124] Formulas for calculating the temperature field distribution at various locations within the tunnel under different altitude factors (TH0-TH6) during fitting working conditions:

[0125] T = B + B1X + B2×10 -4 X 2 +B3×10 -7 X 3 (4a)

[0126] B = 23.457 - 4.969H + 0.073H 2 (4b)

[0127] B1=0.05717+0.01425H+1.8125×10 -4 H 2 (4c)

[0128] B2=-1.70975-0.37094H-0.00911H 2 (4d)

[0129] B3=1.80456+0.34141H+0.01453H 2 (4e)

[0130] In the formula: T is the temperature, °C; H is the altitude, km; X is the distance from the working face, m;

[0131] Formulas (4a) to (4e) can be used to obtain the temperature change inside the tunnel at any altitude with a surrounding rock temperature of 40℃, and can also be used to predict the distance between the 28℃ isotherm and the tunnel face at any altitude.

[0132] Figure 7 A schematic diagram of steps 1-4 is provided. See also... Figure 7 In step 1-4-1, finite element analysis is performed on the test conditions to obtain the influence of ground temperature change at constant altitude on the temperature field inside the tunnel.

[0133] In this embodiment, a standard double-track railway tunnel is selected as the cross-section, with a cross-sectional area of ​​82m². 2 The duct diameter is 1.8m. The physical model dimensions, duct layout location, and origin (0, 0, 0) position are as follows: Figure 6 As shown, the air duct inlet is 20m from the working face. Table 3 shows the temperature field changes at an altitude of 4km and ground temperatures of 40℃, 50℃, 60℃, 70℃, and 80℃. The air supply temperature is set based on the ambient temperature measured in the project, referencing the Sichuan-Tibet Railway project; the excavation face temperature is the residual temperature of the working face after the explosive detonation, selected as 70℃ here.

[0134] Table 3 Test Conditions

[0135]

[0136] The CFD (Computational Fluid Dynamics) numerical method was used to simulate the airflow changes and temperature field distribution within the tunnel under various transient conditions. Multiple monitoring points were selected along the longitudinal direction of the tunnel to monitor the temperature changes at each location during the transient development of the airflow.

[0137] In step 1-4-1, the temperature calculation formula under the ground temperature change is determined based on the fitting results of the ground temperature and location data.

[0138] Figure 8 Temperature distribution curves inside the tunnel under HT4, HT5, HT6, HT7, and HT8 operating conditions are given. (See [reference]) Figure 8 It was found that T and X have a cubic nonlinear relationship within the tunnel.

[0139] The formula for calculating the temperature change at different locations in the tunnel under the fitted working conditions HT4-HT8 is as follows:

[0140] T = C + C1X + C2×10 -4 X 2 +C3×10 -7 X 3 (5a)

[0141] C=-3.87837+0.2301T′+1.40214×10 -5 T′ 2 (5b)

[0142] C1=0.00901+0.00286T′-4.7514×10 -6 T′ 2 (5c)

[0143] C2=0.04529-0.09584T′+2.67621×10 -4 T′ 2 (5d)

[0144] C3=-0.46055+0.11463T′-4.22264×10 -4 T′ 2 (5e)

[0145] In the formula: T is the temperature, °C; X is the distance from the working face, m; T' is the ground temperature, °C;

[0146] Formulas (5a) to (5e) can be used to obtain the temperature change inside the tunnel at any ground temperature at an altitude of 4km, and can also be used to obtain the distance of the 28℃ isotherm from the tunnel face.

[0147] In steps 1-5, the temperature comfort zone range inside the tunnel is predicted based on the temperature calculation formula at any altitude and ground temperature.

[0148] The method for determining the comfortable temperature zone inside a tunnel, taking into account altitude and ground temperature, is applied to the range of isotherm distributions from the tunnel face when the tunnel has an altitude of 6300m, a ground temperature of 55℃, and a predicted temperature of 28℃.

[0149] Substituting H = 6300 into formulas (4a) to (4e) and T' = 55℃ into formulas (5a) to (5e), ​​we obtain formulas (6) and (7):

[0150] T=-4.95033+0.15414X-4.40825×10 -4 ×X 2 +4.53214×10 -7 ×X 3 (6)

[0151] T=8.81954+0.15194X-4.41636×10 -4 ×X 2 +4.56675×10 -7 ×X 3 (7)

[0152] Substituting T = 28℃ into formula (6), we get X = 610m; substituting T = 28℃ into formula (7), we get X = 392m.

[0153] As shown in Table 4, formula (6) is for case 2, and formula (7) is for case 3. Compare the range of distance X from the working face at 28℃ in the three cases:

[0154] Table 4 Comparison of the three scenarios

[0155]

[0156] Comparing scenarios 1 and 2, with increasing altitude, the distance X from the working face to the 28℃ zone increases; comparing scenarios 1 and 3, with increasing ground temperature, the distance X from the working face to the 28℃ zone decreases. Therefore, the distance X from the working face to the 28℃ zone at a ground temperature of 55℃ and an altitude of 6.3km is ∈ (X3). <X<X2),X∈(392,610)。

[0157] In actual tunnel construction, determining the ventilation length is one of the important factors that troubles those involved. To determine the ventilation length, a parameter is introduced. In drill-and-blast excavation, excluding transportation operations, the working area spans from the front face to the lining trolley at the rear. The length of this working area is called the secondary lining step distance L0. The ventilation length is taken as the smaller value between the secondary lining step distance and the smoke exhaust safety distance.

[0158] L0=k0l0 (8)

[0159] In the formula, k0 is the safety factor, which is taken as 1.2; l0 is the length of the stun gun throw, which was calculated to be 88.8m, and L0 is calculated to be 107m.

[0160] The temperature comfort zone X∈(392,610) calculated above covers the secondary lining step distance, and therefore can meet the specification requirements for the temperature within the space of an excavation cycle.

[0161] To make this invention more universal, the effects of various parameter selections on the formula are explained below:

[0162] (1) The present invention uses the standard cross section of a double-track railway tunnel as the physical model. The cross section shape will not affect the calculation results, but the cross section area will affect the calculation of the required air volume. The cross section area in the actual project is substituted into the above-mentioned design required air volume calculation process.

[0163] (2) The duct diameter is 1.8m, and the duct velocity is calculated by dividing the required air volume by the duct cross-sectional area.

[0164] (3) The advance per cycle varies depending on the grade of the surrounding rock. The higher the grade of the surrounding rock, the smaller the advance per cycle.

[0165] (4) Assuming uniform CO generation within the smoke grenade throwing range, the formula for the smoke grenade throwing distance l0 is:

[0166]

[0167] It is known that the throwing distance of the smoldering material is affected by the mass of the explosive.

[0168] (5) Ambient temperature: The temperature is obtained from on-site measurements, or the ambient temperature at other altitudes is calculated from the known ambient temperature at a certain location.

[0169] Compared with existing technologies, this invention provides a calculation method for determining the comfort temperature zone range within a tunnel, considering the influence of altitude and ground temperature. Specifically, it's a prediction method that considers the impact of altitude and ground temperature on the comfort zone range of a tunnel. This method takes into account the combined effects of both factors, as wind tunnel tests and field measurements cannot capture the coupled influence of these two factors. Therefore, numerical simulation is the method with the lowest time and economic cost, and the results have practical significance. While field measurements are generally more reliable, they are too difficult to perform, and wind tunnel tests struggle to simulate air density changes caused by altitude. Numerical simulation better addresses these issues. In actual tunnel construction, multiple parameters such as tunnel cross-section, ventilation method, duct diameter and placement, and surrounding rock strength vary. This invention considers various parameter settings, flexibly adapting to different tunnel projects and reproducing actual construction conditions. Drill-and-blast construction is widely used in tunnel excavation. Blasting produces various harmful gases and dust. In the special environment of high altitude and high ground temperature, strict requirements are placed on ventilation design. Air temperature directly affects the respiratory health of workers and directly restricts the rational arrangement of construction procedures within the tunnel, indirectly affecting construction progress and budget. The method of this invention has low computational time cost, can simulate various working conditions, has flexible parameter usage, and has a wide range of applications. The results obtained can be combined with multiple methods to verify the rationality and safety of the design.

[0170] Furthermore, this invention proposes a prediction formula for the temperature comfort zone range within tunnels under the influence of two environmental factors: altitude and ground temperature. This provides a theoretical basis for predicting the duration of construction ventilation. The method and calculation formula for determining the comfort zone range within tunnels under the influence of altitude and ground temperature proposed in this invention can determine the temperature comfort zone range during the ventilation and blasting stage of tunnel construction in special environments, clarify the temperature change pattern, provide a theoretical basis for the rational design of tunnel construction sequence layout, and ensure the safety and economic applicability of ventilation in drill-and-blast tunnel construction.

[0171] Figure 9 This is a structural diagram of an embodiment of the system for determining the comfortable temperature zone range inside a tunnel, taking into account altitude and ground temperature, according to the present invention. See also... Figure 9 The system for determining the comfortable temperature zone inside the tunnel, taking into account altitude and ground temperature, includes:

[0172] The parameter and specification acquisition module 901 is used to acquire the tunnel's model parameters, environmental parameters, and design specifications.

[0173] The design air volume requirement module 902 is used to obtain the design air volume requirement under different conditions and the design air volume requirement at different altitudes based on model parameters, environmental parameters and design specifications.

[0174] The design requires the following components in module 902 to obtain airflow:

[0175] The design air volume calculation unit under different conditions is used to calculate the design air volume under different conditions based on model parameters, environmental parameters and design specifications. The design air volume under different conditions includes the calculated air volume for minimum wind speed, the calculated air volume for the maximum number of workers, the calculated air volume for forced ventilation and the calculated air volume for diluting internal combustion exhaust gas.

[0176] The zero-altitude design air volume acquisition unit is used to obtain the design air volume at zero altitude based on the design air volume under different conditions.

[0177] The design air volume calculation unit at different altitudes is used to calculate the design air volume at different altitudes based on the altitude correction factor and the design air volume at zero altitude.

[0178] The duct velocity and supply air temperature acquisition module 903 is used to obtain the duct velocity and supply air temperature required for ventilation at different altitudes based on model parameters, environmental parameters, design air volume requirements under different conditions, and design air volume requirements at different altitudes.

[0179] The duct air velocity and supply air temperature measurement module 903 specifically includes:

[0180] The duct velocity calculation unit is used to calculate the duct velocity required for ventilation based on model parameters, design air volume requirements under different conditions, and design air volume requirements at different altitudes.

[0181] The air supply temperature calculation unit is used to calculate the air supply temperature at different altitudes based on environmental parameters.

[0182] The temperature field change module 904 is used to obtain the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant, based on the duct wind speed required for ventilation and the air supply temperature at different altitudes.

[0183] The temperature field change is obtained from module 904, which specifically includes:

[0184] The temperature field change element is used to obtain the temperature field change in the tunnel when the ground temperature remains constant and the altitude changes, based on the duct wind speed required for ventilation and the air supply temperature at different altitudes.

[0185] The temperature comfort zone range module 905 is used to obtain the temperature comfort zone range inside the tunnel at any altitude and ground temperature based on the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant.

[0186] The temperature comfort zone range is specifically included by module 905 as follows:

[0187] The temperature calculation formula under altitude change is obtained by using a unit to calculate the temperature under altitude change based on the change of temperature field inside the tunnel when the ground temperature remains constant and the altitude changes.

[0188] The temperature calculation formula under ground temperature variation is obtained by using data fitting to obtain the temperature calculation formula under ground temperature variation based on the change of temperature field inside the tunnel when the altitude remains constant.

[0189] The temperature comfort zone calculation unit is used to calculate the temperature comfort zone range inside the tunnel at any altitude and ground temperature based on the temperature calculation formulas for altitude changes and ground temperature changes.

[0190] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0191] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for determining the comfortable temperature zone range inside a tunnel, considering altitude and ground temperature, characterized in that, The method includes: Obtain the tunnel's model parameters, environmental parameters, and design specifications; the model parameters include the tunnel's cross-sectional area, tunnel length, duct diameter, and distance from the duct inlet to the tunnel face; the environmental parameters include the tunnel's location's average annual temperature, altitude, and ground temperature. Based on the model parameters, environmental parameters, and design specifications, the design air volume requirements under different conditions and the design air volume requirements at different altitudes are obtained. Based on the model parameters, the environmental parameters, the design air volume required under different conditions, and the design air volume required at different altitudes, the duct velocity required for ventilation and the supply air temperature at different altitudes are obtained. Based on the required duct velocity for ventilation and the supply air temperature at different altitudes, the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the altitude remains constant are obtained. Specifically, based on the required duct velocity for ventilation and the supply air temperature at different altitudes, finite element analysis is used to obtain the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the altitude remains constant. Based on the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the altitude changes while the altitude remains constant, the range of comfortable temperature inside the tunnel at any altitude and ground temperature is obtained. Specifically, this includes: obtaining a temperature calculation formula for altitude changes using data fitting based on the changes in the temperature field inside the tunnel when the ground temperature remains constant and the altitude changes; obtaining a temperature calculation formula for ground temperature changes using data fitting based on the changes in the temperature field inside the tunnel when the altitude remains constant and the ground temperature changes; and calculating the range of comfortable temperature inside the tunnel at any altitude and ground temperature based on the temperature calculation formulas for altitude changes and ground temperature changes.

2. The method for determining the comfortable temperature zone inside a tunnel considering altitude and ground temperature according to claim 1, characterized in that, The step of obtaining the design air volume requirement under different conditions and at different altitudes based on the model parameters, environmental parameters, and design specifications specifically includes: The design air volume requirements under different conditions are calculated based on the model parameters, environmental parameters, and design specifications. The design air volume requirements under different conditions include the calculated air volume for minimum wind speed, the calculated air volume for maximum number of workers, the calculated air volume for forced ventilation, and the calculated air volume for diluting internal combustion exhaust gases. The design air volume at zero altitude is obtained based on the design air volume under the different conditions described above. Based on the altitude correction factor and the design air volume required at zero altitude, the design air volume required at different altitudes is calculated.

3. The method for determining the comfortable temperature zone inside a tunnel considering altitude and ground temperature according to claim 1, characterized in that, The step of obtaining the required duct velocity and supply air temperature at different altitudes based on the model parameters, environmental parameters, design air volume requirements under different conditions, and design air volume requirements at different altitudes specifically includes: Based on the model parameters, the design air volume required under different conditions, and the design air volume required at different altitudes, calculate the duct velocity required for ventilation. Calculate the air supply temperature at different altitudes based on the environmental parameters.

4. A system for determining the comfortable temperature zone range inside a tunnel, taking into account altitude and ground temperature, characterized in that, The system includes: The parameter and specification acquisition module is used to acquire the tunnel's model parameters, environmental parameters, and design specifications. The module for obtaining the required air volume is used to obtain the required air volume under different conditions and the required air volume at different altitudes based on the model parameters, the environmental parameters and the design specifications. The duct velocity and supply air temperature acquisition module is used to obtain the duct velocity and supply air temperature required for ventilation at different altitudes based on the model parameters, the environmental parameters, the design air volume required under different conditions, and the design air volume required at different altitudes. The temperature field change acquisition module is used to obtain the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant, based on the duct wind speed required for ventilation and the supply air temperature at different altitudes; the temperature field change acquisition module specifically includes: a temperature field change acquisition unit, used to obtain the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the ground temperature changes while the altitude remains constant, based on the duct wind speed required for ventilation and the supply air temperature at different altitudes, using finite element analysis. The temperature comfort zone range acquisition module is used to obtain the temperature comfort zone range inside the tunnel at any altitude and ground temperature based on the changes in the temperature field inside the tunnel when the ground temperature remains constant and the changes in the temperature field inside the tunnel when the altitude remains constant and the ground temperature changes. The temperature comfort zone range acquisition module specifically includes: a temperature calculation formula acquisition unit for altitude changes, used to obtain a temperature calculation formula for altitude changes by using data fitting based on the changes in the temperature field inside the tunnel when the ground temperature remains constant and the altitude changes; a temperature calculation formula acquisition unit for ground temperature changes, used to obtain a temperature calculation formula for ground temperature changes by using data fitting based on the changes in the temperature field inside the tunnel when the altitude remains constant and the ground temperature changes; and a temperature comfort zone range calculation unit, used to calculate the temperature comfort zone range inside the tunnel at any altitude and ground temperature based on the temperature calculation formulas for altitude changes and ground temperature changes.

5. The system for determining the comfortable temperature zone inside a tunnel considering altitude and ground temperature according to claim 4, characterized in that, The module for obtaining the required air volume in the design specifically includes: The design air volume calculation unit under different conditions is used to calculate the design air volume under different conditions based on the model parameters, the environmental parameters and the design specifications; the design air volume under different conditions includes the calculated air volume for minimum wind speed, the calculated air volume for maximum number of workers, the calculated air volume for forced ventilation and the calculated air volume for diluting internal combustion exhaust gas; A unit for obtaining the design air volume at zero altitude is used to obtain the design air volume at zero altitude based on the design air volume under the different conditions described above. The design air volume calculation unit at different altitudes is used to calculate the design air volume at different altitudes based on the altitude correction coefficient and the design air volume at zero altitude.

6. The system for determining the comfortable temperature zone inside a tunnel considering altitude and ground temperature according to claim 4, characterized in that, The module for obtaining duct air velocity and supply air temperature specifically includes: The duct velocity calculation unit is used to calculate the duct velocity required for ventilation based on the model parameters, the design air volume required under different conditions, and the design air volume required at different altitudes. The air supply temperature calculation unit is used to calculate the air supply temperature at different altitudes based on the environmental parameters.

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