Underground comprehensive pipe gallery power cabin plugging selection method based on fire situation

Abstract

The invention discloses an underground comprehensive pipe gallery electric power cabin plugging selection method based on a fire situation, and relates to the technical field of urban underground management. According to the method, FDS fire dynamics simulation software is utilized to construct a blocked underground utility tunnel electric power cabin full-size model and a non-blocked underground utility tunnel electric power cabin full-size model, fire spreading conditions under the two models are simulated, extinguishing time and fire spreading images are recorded, and fire evolution under different conditions is determined; based on the extinguishing time and the fire spreading image, whether plugging is carried out or not is selected, the safety and fireproof performance of the underground comprehensive pipe gallery power cabin are improved, further spreading of the fire is stopped in time, the resident safety is improved, social resources are guaranteed, follow-up reconstruction is facilitated, and resource waste is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of urban underground management, and in particular to a method for selecting a plugging method for an electric compartment of an underground integrated pipe gallery based on a fire situation. Background Art

[0002] An urban underground utility corridor, specifically one that centralizes two or more municipal utility pipelines and related ancillary facilities within a single underground tunnel, with a central passageway for maintenance personnel, is a modern, intensive new type of underground tunnel. It typically accommodates a variety of pipeline types, such as engineering pipelines, electrical wires and cables, gas pipelines, thermal pipelines, optical fiber communications cables, water supply and drainage pipelines, and new energy supply pipelines. Because pipelines have varying fire hazard levels, pipelines of the same fire hazard category are generally placed in the same compartment, such as the power compartment, gas compartment, utility compartment, and sewage compartment.

[0003] Natural gas pipelines within integrated utility corridors have the highest fire hazard classification and are typically housed in separate gas compartments. Due to the large initial investment and unfavorable economic performance of gas compartments, they are rarely used in actual projects. The power compartment, second only to natural gas pipelines in fire hazard classification (Class C), is widely used and often considered the compartment with the highest fire risk within urban integrated utility corridors.

[0004] The power compartment of an integrated utility corridor is a narrow, long space with distinct structural characteristics, where its longitudinal dimensions are much greater than its lateral and vertical dimensions. A cable fire in one location can quickly spread and ignite surrounding cables and combustible materials. This can not only burn the cables and infrastructure within the corridor, causing widespread power and communication outages across the city, but can also damage the corridor's protective structure, leading to collapse and severe economic losses and casualties. Therefore, it is necessary to investigate the development and prevention of cable fires within the power compartment of an integrated utility corridor, and to determine whether cables within the compartment need to be sealed under different circumstances. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for selecting the plugging of the power compartment of an underground integrated pipeline corridor based on fire conditions, so as to improve the above-mentioned technical problems.

[0006] In order to achieve the above-mentioned object of the invention, the embodiment of the present invention provides the following technical solutions:

[0007] A method for selecting a plugging method for an electric compartment of an underground integrated pipe gallery based on a fire situation, comprising:

[0008] S1. Obtain the structural parameters of the power compartment of a city's underground integrated pipeline corridor;

[0009] S2. Based on the structural parameters, a full-scale model of the power compartment of the blocked underground utility corridor and a full-scale model of the power compartment of the non-blocked underground utility corridor are constructed;

[0010] S3. Run a full-scale model of the power compartment of a blocked underground utility corridor and a full-scale model of the power compartment of a non-blocked underground utility corridor to simulate a fire scenario and obtain corresponding fire operation results;

[0011] S4. Based on the fire operation results, determine whether the power compartment of the underground integrated pipeline corridor should be sealed.

[0012] Furthermore, the structural parameters include spatial structure data, dimension data and environmental parameters.

[0013] Furthermore, the method of constructing a full-scale model of the power compartment of a blocked underground integrated pipe gallery and a full-scale model of the power compartment of a non-blocked underground integrated pipe gallery based on the structural parameters includes:

[0014] S2-1. Select the cable type and formulate the cable material ratio;

[0015] S2-2, calculate characteristic diameter;

[0016] S2-3. Determine the resolution index of the dimensionless expression based on actual requirements and the FDS User Manual;

[0017] S2-4, determining a modeling grid size based on the characteristic diameter and the dimensionless expression resolution index;

[0018] S2-5. Based on the Froude similarity criterion, the cable type, the cable material ratio and the modeling grid size, the structural parameters are processed using FDS fire dynamics simulation software to construct the corresponding full-scale model of the power cabin of the blocked underground integrated pipeline corridor and the full-scale model of the power cabin of the non-blocked underground integrated pipeline corridor.

[0019] Furthermore, the cable types include YC cables and RVV cables.

[0020] Furthermore, the calculation formula of the characteristic diameter is:

[0021] ;

[0022] in, represents the characteristic diameter, represents the fire heat release rate, 、 、 represent the ambient air concentration, specific heat capacity of air at constant pressure and ambient air temperature respectively, Represents the acceleration due to gravity.

[0023] Furthermore, the modeling grid size is determined based on the characteristic diameter and the dimensionless expression resolution index, and the corresponding formula is:

[0024] ;

[0025] in, represents the dimensionless expression resolution index, Indicates the modeling grid size in the X-axis direction.

[0026] Furthermore, the full-size model of the power cabin of the blocked underground integrated pipeline corridor and the full-size model of the power cabin of the non-blocked underground integrated pipeline corridor have the same structure, and the corresponding length, width and height are 200m, 4.5m and 2.9m respectively; the full-size model of the power cabin of the blocked underground integrated pipeline corridor also includes fireproof panels on both sides, which are used to block both sides of the full-size model of the power cabin of the blocked underground integrated pipeline corridor.

[0027] Furthermore, the full-scale model of the power compartment of the blocked underground utility corridor and the full-scale model of the power compartment of the non-blocked underground utility corridor are used to simulate fire scenarios, and corresponding fire operation results are obtained, including:

[0028] S3-1. Set the fire source location and simulate igniting the fire source;

[0029] S3-2. Using FDS fire dynamics simulation software, record the combustion conditions of the full-scale model of the power compartment of the blocked underground utility corridor and the full-scale model of the power compartment of the unblocked underground utility corridor, and output the corresponding flameout time and flame spread image;

[0030] The fire operation results include the flameout time and flame spread image corresponding to the full-size model of the power cabin of the blocked underground integrated pipeline corridor and the full-size model of the power cabin of the unblocked underground integrated pipeline corridor.

[0031] Furthermore, the determination of whether to seal the power compartment of the underground integrated pipe gallery based on the fire operation result includes:

[0032] Comparing the flameout times corresponding to the full-scale model of the blocked underground utility corridor power cabin and the full-scale model of the non-blocked underground utility corridor power cabin; if the flameout time of the full-scale model of the blocked underground utility corridor power cabin is less than the flameout time of the full-scale model of the non-blocked underground utility corridor power cabin, the underground utility corridor power cabin of the city is selected to be blocked; otherwise, evaluating the flame spread images corresponding to the full-scale model of the blocked underground utility corridor power cabin and the full-scale model of the non-blocked underground utility corridor power cabin to obtain a corresponding evaluation result; wherein the evaluation result is the degree of damage or the scope of damage;

[0033] Compare the damage degree or damage range corresponding to the full-size model of the blocked underground integrated pipeline corridor power cabin and the full-size model of the non-blocked underground integrated pipeline corridor power cabin; if the damage degree or damage range of the full-size model of the blocked underground integrated pipeline corridor power cabin is less than the damage degree or damage range of the full-size model of the non-blocked underground integrated pipeline corridor power cabin, then the underground integrated pipeline corridor power cabin of the city is chosen to be blocked; otherwise, the underground integrated pipeline corridor power cabin of the city is chosen not to be blocked.

[0034] The effective effects of the present invention are:

[0035] The present invention uses FDS fire dynamics simulation software to construct full-scale models of the power compartment of a blocked underground comprehensive pipeline corridor and a full-scale model of the power compartment of an unblocked underground comprehensive pipeline corridor, simulates the fire spread under the two models, and records the extinguishing time and fire spread image, and determines the fire evolution under different situations; based on the extinguishing time and fire spread image, it is determined whether to block the power compartment, thereby improving the safety and fire resistance of the power compartment of the underground comprehensive pipeline corridor, and promptly stopping the further spread of the fire, thereby improving the safety of residents and protecting social resources, and facilitating subsequent reconstruction and reducing resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 is a flow chart of a method in an embodiment of the present invention;

[0038] Figure 2 Schematic diagram of a full-scale model of the power compartment of the underground integrated pipeline gallery in an embodiment of the present invention;

[0039] Figure 3 Schematic diagram of the fire source position in an embodiment of the present invention;

[0040] Figures 4(a) to 4(g) are flame spread images of a full-scale model of a power compartment of a non-blocked underground utility corridor according to an embodiment of the present invention at different times; Figure 4(a) is a flame spread image corresponding to 10 seconds, Figure 4(b) is a flame spread image corresponding to 60 seconds, Figure 4(c) is a flame spread image corresponding to 130 seconds, Figure 4(d) is a flame spread image corresponding to 200 seconds, Figure 4(e) is a flame spread image corresponding to 350 seconds, Figure 4(f) is a flame spread image corresponding to 420 seconds, and Figure 4(g) is a flame spread image corresponding to 470 seconds.

[0041] Figures 5(a) to 5(b) are schematic diagrams showing the degree of damage to a full-scale model of a power compartment in a non-blocked underground utility corridor according to an embodiment of the present invention; Figure 5(a) is a front view showing the degree of damage, and Figure 5(b) is a top view showing the degree of damage;

[0042] Figures 6(a) to 6(g) are flame spread images of a full-scale model of a power compartment of a sealed underground utility corridor at different times in an embodiment of the present invention; Figure 6(a) is a flame spread image corresponding to 10 seconds, Figure 6(b) is a flame spread image corresponding to 60 seconds, Figure 6(c) is a flame spread image corresponding to 130 seconds, Figure 6(d) is a flame spread image corresponding to 200 seconds, Figure 6(e) is a flame spread image corresponding to 350 seconds, Figure 6(f) is a flame spread image corresponding to 420 seconds, and Figure 6(g) is a flame spread image corresponding to 470 seconds.

[0043] FIG7 (a) to FIG7 (b) are schematic diagrams showing the degree of damage of a full-scale model of a power compartment of a sealed underground utility corridor according to an embodiment of the present invention; FIG7 (a) is a front view showing the degree of damage, and FIG7 (b) is a top view showing the degree of damage;

[0044] Figures 8(a) to 8(f) are temperature change curves of the thermocouple bundle at different positions of the experimental platform corresponding to working condition 1 in an embodiment of the present invention; Figure 8(a) is a temperature change curve of the thermocouple bundle at 0 m from the center of the experimental platform, Figure 8(b) is a temperature change curve of the thermocouple bundle at 0.5 m from the center of the experimental platform, Figure 8(c) is a temperature change curve of the thermocouple bundle at 1 m from the center of the experimental platform, Figure 8(d) is a temperature change curve of the thermocouple bundle at 3 m from the center of the experimental platform, Figure 8(e) is a temperature change curve of the thermocouple bundle at 5 m from the center of the experimental platform, and Figure 8(f) is a temperature change curve of the thermocouple bundle at 7 m from the center of the experimental platform;

[0045] Figures 9(a) to 9(f) are temperature change curves of the thermocouple bundle at different positions of the experimental platform corresponding to working condition 2 in an embodiment of the present invention; Figure 9(a) is a temperature change curve of the thermocouple bundle at 0 m from the center of the experimental platform, Figure 9(b) is a temperature change curve of the thermocouple bundle at 0.5 m from the center of the experimental platform, Figure 9(c) is a temperature change curve of the thermocouple bundle at 1 m from the center of the experimental platform, Figure 9(d) is a temperature change curve of the thermocouple bundle at 3 m from the center of the experimental platform, Figure 9(e) is a temperature change curve of the thermocouple bundle at 5 m from the center of the experimental platform, and Figure 9(f) is a temperature change curve of the thermocouple bundle at 7 m from the center of the experimental platform;

[0046] Figures 10(a) to 10(f) are temperature change curves of the thermocouple bundle at different positions of the experimental platform corresponding to working condition 3; among them, Figure 10(a) is the temperature change curve of the thermocouple bundle at 0 m from the center of the experimental platform, Figure 10(b) is the temperature change curve of the thermocouple bundle at 0.5 m from the center of the experimental platform, Figure 10(c) is the temperature change curve of the thermocouple bundle at 1 m from the center of the experimental platform, Figure 10(d) is the temperature change curve of the thermocouple bundle at 3 m from the center of the experimental platform, Figure 10(e) is the temperature change curve of the thermocouple bundle at 5 m from the center of the experimental platform, and Figure 10(f) is the temperature change curve of the thermocouple bundle at 7 m from the center of the experimental platform;

[0047] Figures 11(a) to 11(f) are temperature change curves of the thermocouple bundle at different positions of the experimental platform corresponding to working condition 4; among them, Figure 11(a) is the temperature change curve of the thermocouple bundle at 0 m from the center of the experimental platform, Figure 11(b) is the temperature change curve of the thermocouple bundle at 0.5 m from the center of the experimental platform, Figure 11(c) is the temperature change curve of the thermocouple bundle at 1 m from the center of the experimental platform, Figure 11(d) is the temperature change curve of the thermocouple bundle at 3 m from the center of the experimental platform, Figure 11(e) is the temperature change curve of the thermocouple bundle at 5 m from the center of the experimental platform, and Figure 11(f) is the temperature change curve of the thermocouple bundle at 7 m from the center of the experimental platform. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and represented in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0049] See also Figure 1 This embodiment provides a method for selecting a plugging method for an underground utility corridor power compartment based on a fire situation, which includes:

[0050] S1. Obtain the structural parameters of the power compartment of a city's underground integrated pipeline corridor;

[0051] The structural parameters include spatial structural data, dimension data and environmental parameters.

[0052] S2. Based on the structural parameters, a full-scale model of the power compartment of the blocked underground utility corridor and a full-scale model of the power compartment of the non-blocked underground utility corridor are constructed;

[0053] The Froude model, pressure model, and analogy model are three reliable experimental models for studying fires in narrow and long spaces, each corresponding to different similarity criteria. Each model has its own specific application scenarios. Among them, the pressure model is mainly applicable to flow and combustion processes where the Rayleigh number (Re) has a significant impact, while the analogy model uses two fluid media with different densities to simulate the smoke flow process. Compared with the pressure model and analogy model, the Froude model is mainly applicable to buoyancy-driven smoke flow and heat conduction processes and can be carried out under normal conditions. Therefore, the full-scale model of the power compartment of the blocked underground integrated pipeline corridor and the full-scale model of the power compartment of the unblocked underground integrated pipeline corridor adopts the Froude scale model.

[0054] The method of constructing a full-scale model of the power compartment of a blocked underground utility corridor and a full-scale model of the power compartment of a non-blocked underground utility corridor based on the structural parameters includes:

[0055] S2-1. Select the cable type and formulate the cable material ratio;

[0056] The cable types include YC cables and RVV cables.

[0057] S2-2, calculate characteristic diameter;

[0058] The calculation formula of the characteristic diameter is:

[0059] ;

[0060] in, represents the characteristic diameter, Indicates the fire heat release rate in kW. 、 、 They represent the ambient air concentration, specific heat capacity of air at constant pressure and ambient air temperature, respectively, and their units are kg / m 3 , kJ / (kg·k), K, Indicates the acceleration due to gravity in m / s 2 .

[0061] S2-3. Determine the dimensionless expression resolution index based on actual requirements and the FDS user manual. In the FDS user manual, the dimensionless expression resolution index ranges from 4 to 16.

[0062] S2-4, determining a modeling grid size based on the characteristic diameter and the dimensionless expression resolution index;

[0063] The modeling grid size is determined based on the characteristic diameter and the dimensionless expression resolution index, and the corresponding formula is:

[0064] ;

[0065] in, represents the dimensionless expression resolution index, Indicates the modeling grid size in the X-axis direction. The corresponding grid sizes in the Y-axis and Z-axis directions are the same as the grid size in the X-axis direction. The modeling grid size of the present invention is 0.1m.

[0066] S2-5. Based on the Froude similarity criterion, the cable type, the cable material ratio, and the modeling grid size, the structural parameters are processed using FDS fire dynamics simulation software to construct corresponding full-scale models of the power compartment of the blocked underground utility corridor and the power compartment of the unblocked underground utility corridor. To better simulate the flow of fire smoke during a fire, that is, a typical thermal buoyancy-driven motion process, the Froude similarity criterion is used to construct the full-scale models of the power compartment of the blocked underground utility corridor and the power compartment of the unblocked underground utility corridor.

[0067] The full-size model of the power cabin of the blocked underground integrated pipeline corridor and the full-size model of the power cabin of the non-blocked underground integrated pipeline corridor have the same structure, and the corresponding length, width and height are 200m, 4.5m and 2.9m respectively; the full-size model of the power cabin of the blocked underground integrated pipeline corridor also includes fireproof panels on both sides, which are used to block both sides of the full-size model of the power cabin of the blocked underground integrated pipeline corridor.

[0068] S3. Run a full-scale model of the power compartment of a blocked underground utility corridor and a full-scale model of the power compartment of a non-blocked underground utility corridor to simulate a fire scenario and obtain corresponding fire operation results;

[0069] The fire scenario simulation is performed on the full-scale model of the power compartment of the blocked underground comprehensive pipeline corridor and the full-scale model of the power compartment of the non-blocked underground comprehensive pipeline corridor to obtain corresponding fire operation results, including:

[0070] S3-1. Set the fire source location and simulate igniting the fire source;

[0071] S3-2. Using FDS fire dynamics simulation software, record the combustion conditions of the full-scale model of the power compartment of the blocked underground utility corridor and the full-scale model of the power compartment of the unblocked underground utility corridor, and output the corresponding flameout time and flame spread image;

[0072] The fire operation results include the flameout time and flame spread image corresponding to the full-size model of the power cabin of the blocked underground integrated pipeline corridor and the full-size model of the power cabin of the unblocked underground integrated pipeline corridor.

[0073] S4. Based on the fire operation results, determine whether the power compartment of the underground integrated pipeline corridor should be sealed.

[0074] The determination of whether to seal the power compartment of the underground integrated pipe gallery based on the fire operation results includes:

[0075] Comparing the flameout times corresponding to the full-scale model of the blocked underground utility corridor power cabin and the full-scale model of the non-blocked underground utility corridor power cabin; if the flameout time of the full-scale model of the blocked underground utility corridor power cabin is less than the flameout time of the full-scale model of the non-blocked underground utility corridor power cabin, the underground utility corridor power cabin of the city is selected to be blocked; otherwise, evaluating the flame spread images corresponding to the full-scale model of the blocked underground utility corridor power cabin and the full-scale model of the non-blocked underground utility corridor power cabin to obtain a corresponding evaluation result; wherein the evaluation result is the degree of damage or the scope of damage;

[0076] Compare the damage degree or damage range corresponding to the full-size model of the blocked underground integrated pipeline corridor power cabin and the full-size model of the non-blocked underground integrated pipeline corridor power cabin; if the damage degree or damage range of the full-size model of the blocked underground integrated pipeline corridor power cabin is less than the damage degree or damage range of the full-size model of the non-blocked underground integrated pipeline corridor power cabin, then the underground integrated pipeline corridor power cabin of the city is chosen to be blocked; otherwise, the underground integrated pipeline corridor power cabin of the city is chosen not to be blocked.

[0077] In one embodiment, the power compartment of the utility corridor in a certain area is selected, and the corresponding structural parameters are obtained to construct the corresponding full-scale model of the power compartment of the blocked underground utility corridor and the full-scale model of the power compartment of the non-blocked underground utility corridor, such as Figure 2 shown.

[0078] Place the ignition device just below the bottom of the bridge as the fire source location, e.g. Figure 3 shown.

[0079] The fire scenario simulation was performed using FDS fire dynamics simulation software. The flame spread images of the full-scale model of the power compartment of the non-blocked underground integrated pipeline corridor at different times are shown in Figures 4(a) to 4(g). In the non-blocked case, the flame did not show a V-shape when the cable was ignited at the beginning. At 60s, the flame could be seen touching the ceiling of the pipeline corridor, and the ceiling flame spread to both sides, showing the unique V-shape of the cable fire. At 130s, the cable above the ignition source was burned, and obvious gaps could be seen. At 200s, the cable burned in a V-shape, and the cables on each layer spread to both sides. At around 350s, the fire development reached its peak, and it could be seen that the middle part of the cable had been burned. At 420s, the flame could be seen to be smaller, just as the heat release rate curve corresponds to the heat release rate dropped to about 7000kW at 420s. However, at 470s, the flame was seen to reignite violently near the openings on both sides of the pipeline corridor, and the heat release rate increased. By the end of the simulation, partial flames could be seen at the opening of the pipeline corridor. The damage degree corresponding to the full-scale model of the power compartment of the non-blocked underground integrated pipeline corridor is shown in Figure 5 (a) and Figure 5 (b). The damage degree of the full-scale model of the power compartment of the non-blocked underground integrated pipeline corridor is as follows: most of the cables in the middle are burned, and the cables near the opening of the pipeline corridor have been burned to a large extent.

[0080] Figures 6(a) through 6(g) show flame spread images of the full-scale model of the power compartment of a blocked underground utility corridor at different times. Under the blocked condition, the flame development was relatively consistent in the early stages of the two conditions. At 310 seconds, the fire in the cable corridor reached its peak under the blocked condition, with the heat release rate reaching its maximum. The flames had already spread extensively to both sides of the corridor. However, no rekindling was observed under the blocked condition. The corresponding damage levels for the full-scale model of the power compartment of a blocked underground utility corridor are shown in Figures 7(a) and 7(b). The damage level for the full-scale model of the power compartment of a blocked underground utility corridor is as follows: most of the cables in the center were burned, while cables near the openings on both sides of the corridor showed no obvious signs of burning, a significant difference from the unblocked condition.

[0081] It can be seen that the choice of sealing the power compartment of the integrated pipeline corridor in the area can further prevent the spread of fire, reduce the loss of social resources, and facilitate subsequent reconstruction.

[0082] In another embodiment, an experimental platform corresponding to a full-scale model of a sealed underground utility corridor power compartment and a full-scale model of an unsealed underground utility corridor power compartment was constructed at a scale of 1:10, with the corresponding length, width, and height being 20m, 0.45m, and 0.23m, respectively. The main surface of the utility corridor power compartment experimental model corresponding to the experimental platform is made of high-temperature resistant fireproof board; for ease of observation, the front of the utility corridor power compartment experimental model is made of fireproof glass; the entire utility corridor power compartment experimental model is constructed of a steel frame, and all steel frames are combined. A cable tray is installed at the center (10m) of the utility corridor power compartment experimental model. The cable tray is made of stainless steel and has a total of 6 layers, with a spacing of 2.0cm between each layer. The cable tray is designed to be movable, facilitating the placement and removal of cables before and after the experiment. The cables are secured with wire from both sides and straightened to prevent uneven cable arrangement due to collapse in the middle of the cable.

[0083] A propane gas ignition device is placed directly below the bottom of the bridge (the fire source) to ignite the cable, extinguishing it after it is ignited. A camera is set up directly in front of the fireproof glass to record the combustion changes and flame spread of the cable during the combustion process.

[0084] Thermocouple bundles were placed at 0m, 0.5m, 1m, 3m, 5m, and 7m from the center of the test model of the integrated pipeline corridor power compartment. Thermocouple bundles near the fire source were all high-temperature K-type armored thermocouples with a diameter of 1mm and a measurement temperature range of 0 to 1000°C. Thermocouple bundles near other locations were all medium- and low-temperature standard K-type thermocouples with a wire diameter of 2 x 0.3mm and a sheath diameter of 1.5mm. All temperature data was recorded and stored in real time using an MT-X multi-channel temperature collector with a sampling frequency of 1s.

[0085] The YC and RVV cables were tested. Both were 3×4 cables with an inner core consisting of three copper wires with a cross-sectional area of ​​4 square millimeters and a diameter of approximately 11 mm. The cable material parameters are shown in Table 1.

[0086] Table 1

[0087]

[0088] The different experimental working condition settings of YC cable and RVV cable are shown in Table 2.

[0089] Table 2

[0090]

[0091] For both YC cables and RVV cables, when blocked, the corresponding self-extinguishing time is shorter than that when not blocked.

[0092] As shown in Figures 8(a) to 8(e), after ignition in Condition 1, the temperature directly above the fire source rises rapidly; around 120 seconds later, the ceiling reaches its maximum temperature, reaching 750°C. As the distance from the fire source increases, the maximum ceiling temperature to the left of the fire source decreases. For example, the maximum ceiling temperature to the left of the fire source drops from 450°C to 5°C. This decrease in flue gas temperature is due to heat exchange with the wall and heat loss from the entrained air during the smoke spread process.

[0093] As shown in Figure 9 (a) to Figure 9 (e), after the ignition of working condition 2, the temperature directly above the fire source position rises rapidly, and the ceiling reaches the highest temperature of 790°C around 70 seconds, indicating that the blocking method in the cable fire in the corridor will cause the temperature at the middle fire source to intensify; at the same time, by comparing the temperatures of each point corresponding to working conditions 1 and 2 on the left side of the fire source position, it can be seen that the temperature of working condition 1 is higher than that of working condition 2. For example, the maximum ceiling temperature corresponding to working condition 1 at 3m to the left of the fire source position is 27°C, while the temperature at the same position in working condition 2 is 15°C. For example, the maximum ceiling temperature corresponding to working condition 1 at 5m to the left of the fire source position is 15°C, while the temperature at the same position in working condition 2 is 9°C. This shows that the existence of blocking on both sides of the corridor inhibits the movement of high-temperature smoke in the corridor to both sides, thereby preventing the spread of the fire.

[0094] As shown in Figures 10(a) to 10(e), after ignition in Condition 3, the temperature directly above the fire source reaches its maximum temperature of 750°C around 40 seconds after ignition. The temperatures at various points on the left side also indicate that the ceiling has the highest temperature, decreasing with increasing distance from the ceiling, forming a distinct smoke stratification. Furthermore, due to the settling of the smoke layer, the maximum temperature on the left side of the ceiling decreases as the distance from the fire source increases.

[0095] As shown in Figures 11(a) to 11(e), due to the blocking method used on both sides of the tunnel in this area, after ignition in Condition 4, the corresponding temperature at the ceiling directly above the fire source reached a maximum temperature of 800°C, which is higher than the 750°C in Condition 3. At the same time, the temperature rise at each point on the left side shows that the temperature on the left side of Condition 4 is slightly lower than that of Condition 3. This indicates that the blocking method causes the high-temperature smoke in the tunnel to concentrate in the center of the tunnel. Therefore, the temperature at the ceiling corresponding to Condition 4 is higher than that of Condition 3, while the temperature on both sides of Condition 4 is lower than that of Condition 3. This verifies the fire operation results corresponding to the full-scale model of the power compartment of the blocked underground integrated tunnel and the full-scale model of the power compartment of the unblocked underground integrated tunnel. In this area, the blocking method on both sides can effectively control the high-temperature smoke in the tunnel to move to the sides, concentrating the high temperature in the center of the tunnel and preventing the fire source from receiving fresh air, resulting in rapid self-extinguishing, thus achieving the purpose of preventing and controlling tunnel cable fires.

[0096] Based on the experimental data of the above-mentioned experimental platform, the blocking of the power compartment of the integrated pipeline corridor can better prevent the spread of fire, and the degree of loss and self-extinguishing time are smaller.

[0097] In summary, the present invention uses FDS fire dynamics simulation software to construct full-scale models of the blocked underground utility corridor power compartment and the non-blocked underground utility corridor power compartment, simulates the fire spread under the two models, and records the extinguishing time and fire spread image, and determines the fire evolution under different situations; based on the extinguishing time and fire spread image, it is determined whether to block the compartment, thereby improving the safety and fire resistance of the underground utility corridor power compartment, and promptly stopping the further spread of the fire, thereby improving the safety of residents and protecting social resources, and facilitating subsequent reconstruction and reducing resource waste.

[0098] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for selecting the plugging of the power compartment of an underground integrated pipe gallery based on fire conditions, characterized in that: include: S1. Obtain the structural parameters of the power compartment of an underground comprehensive pipeline corridor in a certain city; S2. Based on the structural parameters, a full-scale model of the power cabin of the blocked underground utility corridor and a full-scale model of the power cabin of the non-blocked underground utility corridor are constructed; S3. Run the full-scale model of the blocked underground utility corridor power compartment and the full-scale model of the non-blocked underground utility corridor power compartment to simulate the fire scenario and obtain the corresponding fire operation results; S4. Based on the fire operation results, determine whether the power compartment of the underground integrated pipeline corridor should be sealed.

2. The method for selecting the plugging of the power compartment of the underground integrated pipe gallery based on the fire situation according to claim 1 is characterized in that: The structural parameters include spatial structural data, dimension data and environmental parameters.

3. The method for selecting the plugging of the power compartment of the underground integrated pipe gallery based on the fire situation according to claim 1 is characterized in that: The method of constructing a full-scale model of a power cabin for a blocked underground utility corridor and a full-scale model of a power cabin for a non-blocked underground utility corridor based on structural parameters includes: S2-1. Select the cable type and formulate the cable material ratio; S2-2, calculate characteristic diameter; S2-3. Determine the resolution index of the dimensionless expression based on actual requirements and the FDS User Manual; S2-4, determining a modeling grid size based on the characteristic diameter and the dimensionless expression resolution index; S2-5. Based on the Froude similarity criterion, the cable type, the cable material ratio and the modeling grid size, the structural parameters are processed using FDS fire dynamics simulation software to construct the corresponding full-size model of the power cabin of the blocked underground comprehensive pipeline corridor and the full-size model of the power cabin of the non-blocked underground comprehensive pipeline corridor.

4. The method for selecting the plugging of the power compartment of the underground integrated pipe gallery based on the fire situation according to claim 3 is characterized in that: The cable types include YC cables and RVV cables.

5. The method for selecting the plugging of the power compartment of the underground integrated pipe gallery based on the fire situation according to claim 3 is characterized in that: The calculation formula of the characteristic diameter is: ； in, represents the characteristic diameter, represents the fire heat release rate, , , represent the ambient air concentration, specific heat capacity of air at constant pressure and ambient air temperature respectively, Represents the acceleration due to gravity.

6. The method for selecting the plugging of the power compartment of the underground integrated pipe gallery based on the fire situation according to claim 5 is characterized in that: The modeling grid size is determined based on the characteristic diameter and the dimensionless expression resolution index, and the corresponding formula is: ； in, represents the dimensionless expression resolution index, Indicates the modeling grid size in the X-axis direction.

7. The method for selecting the plugging of the power compartment of the underground integrated pipe gallery based on the fire situation according to claim 3 is characterized in that: The full-size model of the power cabin of the blocked underground comprehensive pipeline corridor and the full-size model of the power cabin of the non-blocked underground comprehensive pipeline corridor have the same structure, and the corresponding length, width and height are 200m, 4.5m and 2.9m respectively; the full-size model of the power cabin of the blocked underground comprehensive pipeline corridor also includes fireproof panels on both sides, which are used to block both sides of the full-size model of the power cabin of the blocked underground comprehensive pipeline corridor.

8. The method for selecting the plugging of the power compartment of the underground integrated pipe gallery based on the fire situation according to claim 1 is characterized in that: The operation of the full-scale model of the power cabin of the blocked underground utility corridor and the full-scale model of the power cabin of the non-blocked underground utility corridor is used to simulate the fire scenario, and the corresponding fire operation results are obtained, including: S3-1. Set the fire source location and simulate igniting the fire source; S3-2, using FDS fire dynamics simulation software to record the combustion conditions of the full-size model of the power cabin of the blocked underground utility corridor and the full-size model of the power cabin of the unblocked underground utility corridor, and output the corresponding flameout time and flame spread image; The fire operation results include the flameout time and the flame spread image corresponding to the full-size model of the power cabin of the blocked underground comprehensive pipeline corridor and the full-size model of the power cabin of the unblocked underground comprehensive pipeline corridor.

9. The method for selecting the plugging of the power compartment of the underground integrated pipe gallery based on the fire situation according to claim 8 is characterized in that: The determination of whether to seal the power compartment of the underground utility corridor based on the fire operation result includes: Compare the flameout times corresponding to the full-size model of the blocked underground utility corridor power cabin and the full-size model of the non-blocked underground utility corridor power cabin; if the flameout time of the full-size model of the blocked underground utility corridor power cabin is less than that of the non-blocked underground utility corridor power cabin, the underground utility corridor power cabin of the city is selected to be blocked; otherwise, evaluate the flame spread images corresponding to the full-size model of the blocked underground utility corridor power cabin and the full-size model of the non-blocked underground utility corridor power cabin to obtain corresponding evaluation results; wherein, the evaluation results are the degree of damage or the scope of damage; Compare the damage degree or damage range corresponding to the full-size model of the power cabin of the blocked underground comprehensive pipeline corridor and the full-size model of the power cabin of the unblocked underground comprehensive pipeline corridor; if the damage degree or damage range of the full-size model of the power cabin of the blocked underground comprehensive pipeline corridor is less than the damage degree or damage range of the full-size model of the power cabin of the unblocked underground comprehensive pipeline corridor, the power cabin of the underground comprehensive pipeline corridor of the city is chosen to be blocked; otherwise, the power cabin of the underground comprehensive pipeline corridor of the city is chosen not to be blocked.

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