A method for optimizing the layout of ventilation shafts in long tunnel sections

Abstract

This invention discloses a method for optimizing the layout of ventilation shafts in long tunnel sections, comprising the following steps: calculating the train operation curve within the long tunnel section; based on the required number of ventilation shafts *n*, initially determining the placement of each ventilation shaft and the length of each ventilation shaft section by dividing the long tunnel section into equal parts according to the principle of length; calculating the tracking interval time; verifying whether each ventilation shaft section can meet the tracking interval time requirement; if it cannot meet the requirement, adjusting the corresponding ventilation shaft positions and re-verifying until the tracking interval time requirement is met; and outputting the ventilation shaft layout scheme to the HMI interface. The advantages of this invention are: it meets the throughput requirements of long tunnel sections and also satisfies the safety constraint that only one train can pass through each ventilation shaft section.

Description

Technical Field

[0001] This invention relates to the field of rail transit signaling technology, and more specifically to a method for optimizing the layout design of ventilation shafts in long tunnel sections. Background Technology

[0002] Subways are enclosed spaces with high passenger density and limited evacuation conditions, making them extremely dangerous in the event of a fire. While train fires causing serious damage are rare, their impact is immense if they occur. Therefore, minimizing the impact of fires is a key focus of subway research, and the layout of intermediate ventilation shafts is one aspect of this.

[0003] According to the design specifications for urban rapid rail transit, the signaling system between two ventilation shafts in ATO mode only allows one train to operate at a time. If two trains are in a ventilation section, and a fire breaks out at the rear of the train in front, the train behind will be in a smoke-filled area, affecting passenger evacuation and potentially leading to more disastrous consequences.

[0004] Currently, the principle for determining whether to set up an intermediate ventilation shaft in actual engineering is as follows: determine the relationship between the pure running time T between the piston ventilation shafts at the ends of the tunnel section and the train interval.

[0005] If T > train interval, then the installation of an intermediate ventilation shaft needs to be considered;

[0006] If T < train interval, then intermediate ventilation shafts are not required.

[0007] The pure running time T between the piston ventilation shafts at the ends of the tunnel is the time difference between the moment the train head enters the piston ventilation shaft at the departure station and the moment the train tail exits the piston ventilation shaft at the arrival station.

[0008] This method is only applicable to ordinary long tunnel sections. If there are long tunnel sections, multiple ventilation shafts need to be installed within the section. Furthermore, the installation of these ventilation shafts must meet certain section design capacity requirements, such as a 150-second tracking interval.

[0009] Long tunnel sections refer to continuous tunnels with a length of 3 kilometers or more between two stations within a tunnel.

[0010] To ensure safe operation in long tunnel sections, the layout of ventilation shafts needs to guarantee both train safety (only one train is allowed per ventilation shaft section) and a 150-second interval.

[0011] Therefore, this invention proposes a ventilation shaft arrangement method to meet the requirements of mixed operation of trains with different formations. Summary of the Invention

[0012] The purpose of this invention is to address the shortcomings of the prior art by providing a ventilation shaft layout optimization design method for long tunnel sections. This ventilation shaft layout optimization design method divides the optimal ventilation shaft sections according to the time interval on the train's running curve in the long tunnel section, the location of the nearest ventilation shaft at the beginning and end of the tunnel.

[0013] The objective of this invention is achieved through the following technical solutions:

[0014] A method for optimizing the layout of ventilation shafts in long tunnel sections, characterized in that the method includes the following steps:

[0015] S1: Calculate the train running curve in a long tunnel section;

[0016] S2: Based on the required number of ventilation shafts n, the long tunnel section is divided into equal sections according to the principle of length to preliminarily determine the layout of each ventilation shaft and the length of the ventilation shaft section;

[0017] S3: Calculate the tracking interval time; verify whether each ventilation shaft section can meet the tracking interval time requirement. If it cannot meet the requirement, adjust the corresponding ventilation shaft position and re-verify until the tracking interval time requirement is met.

[0018] The tracking interval is equal to T0-T1; where T0 is the time when the rear of the preceding train clears the exit of the current ventilation shaft section; at time T0, the front of the following train is located at the most unfavorable safe braking distance from the entrance of the ventilation shaft section, and the time T1 at the most unfavorable safe braking distance is found through the train operation curve.

[0019] The calculation method for the train's running curve is as follows: The train's running curve in a long tunnel section is divided into four stages: the starting stage, the acceleration stage, the cruising stage, and the station braking stage. Data points for each moment in each of these stages are calculated and recorded. These data points include speed, acceleration, kilometer marker position, and the most unfavorable safe braking distance. The data points are then fitted and connected to obtain the train's running curve. The formulas for calculating speed and kilometer marker position at each moment are:

[0020]

[0021] In the formula:

[0022] v i For the present i The speed of time;

[0023] ai For the present i Acceleration at any moment;

[0024] s i For the present i The kilometer marker position at that moment;

[0025] △t The calculation period is the duration between adjacent moments. △t ≤500ms.

[0026] The calculation method for the most unfavorable safe braking distance is as follows: the braking distance of the train under the most unfavorable condition includes three stages;

[0027] The calculation method for the distance traveled during the first stage of uncontrolled acceleration is as follows:

[0028]

[0029] The second stage braking distance calculation method is as follows:

[0030]

[0031] The method for calculating the braking distance in the third stage is as follows:

[0032]

[0033] The most unfavorable safe braking distance is s = s 1 + s 2 + s 3 ;

[0034] In the formula:

[0035] △t For the calculation period;

[0036] a runaway This represents the runaway acceleration value.

[0037] a grade This represents the acceleration value caused by the slope.

[0038] v 0 The initial speed at which the train begins emergency braking under the most unfavorable conditions;

[0039] t 1 The duration of the runaway acceleration during the first phase. t1 =∑ △t ;

[0040] s 1 The first stage of uncontrolled acceleration covers a certain distance;

[0041] v 1 This is the speed at which the first stage of uncontrolled acceleration ends.

[0042] t 2 This refers to the duration of the runaway acceleration during the second phase. t 2 =∑ △t ;

[0043] s 2 The operating distance for switching to emergency braking in the second stage;

[0044] v 2 This is the speed value for switching to emergency braking in the second stage;

[0045] a eb This is the minimum guaranteed emergency braking rate for the train;

[0046] s 3 This refers to the emergency braking distance in the third stage.

[0047] The minimum length of each ventilation shaft section is greater than the length of the train.

[0048] The advantages of this invention are that it meets the throughput requirements of long tunnel sections and also meets the safety restriction that only one train can pass through each ventilation shaft section. Attached Figure Description

[0049] Figure 1 This is a flowchart of the ventilation shaft layout optimization design method in this invention;

[0050] Figure 2 This is a schematic diagram illustrating the calculation of the train tracking interval before and after the ventilation shaft in this invention;

[0051] Figure 3 This is a schematic diagram of the train operation curve in the long tunnel section of this invention;

[0052] Figure 4 This is a schematic diagram showing the composition of the ventilation shaft layout optimization design method module in this invention;

[0053] Figure 5 This is a schematic diagram of the most unfavorable safe braking distance curve in this invention. Detailed Implementation

[0054] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art:

[0055] Example: Figure 1 , 2 As shown in Figures 3, 4, and 5, this embodiment specifically relates to a method for optimizing the layout of ventilation shafts in long tunnel sections. The operation of this ventilation shaft layout optimization design method is as follows: Figure 4 The system implementation shown includes an HMI module and ventilation shaft layout algorithm module, train operation curve algorithm module, and train tracking interval time algorithm module, which are respectively connected to the HMI module; the ventilation shaft layout optimization design method includes the following steps:

[0056] S1: Based on the train's traction and braking parameters and track conditions, the train operation curve algorithm module calculates the train operation curve for long tunnel sections, including the train's speed, time, position, acceleration, and safe braking distance at each moment. The train operation curve is as follows: Figure 3 As shown, the train operation curve refers to the train's speed, acceleration, kilometer marker position, and most unfavorable safe braking distance at each moment within a long tunnel section. It should be noted that, in this embodiment, a long tunnel section refers to a continuous tunnel with a length of 3 kilometers or more between two stations.

[0057] like Figure 1 , 3 As shown, the train's operating curve within a long tunnel section is divided into four stages: the start-up stage, the acceleration stage, the cruising stage, and the braking stage upon entering the station. During train operation, the following constraints need to be considered: 1. Passenger comfort. 2. Gradient within the tunnel section. 3. Speed ​​limit within the tunnel section. 4. Train length. 5. Traction and braking characteristics constraints of the train.

[0058] To ensure passenger comfort during the initial acceleration phase at the platform, the train uses a relatively low acceleration to move from a standstill. Generally, the starting acceleration is taken as 0.3 m / s². 2 -0.5 m / s 2 Within the range.

[0059] During the acceleration phase, in order to increase the train's speed as quickly as possible and reduce the train's running time within the section, the train accelerates according to the maximum performance of the vehicle to reach the maximum speed limit of the section.

[0060] During the cruise phase, to overcome the effects of gradient and other resistances and maintain a speed close to the limit, the train is permitted to apply a certain traction braking rate. If the train speed is within a certain range below the maximum speed limit during the cruise phase, the train is permitted to activate the coasting function. During coasting, the train's traction braking rate is 0. The coasting function module can be turned on or off while the train is running on a section of track.

[0061] During the braking phase before entering the station, the train's speed and position values ​​at each moment are calculated based on the target distance between the train and the platform stopping point, as well as the train's usual braking rate.

[0062] The data points for each moment in each stage of the train's journey are calculated and recorded. These data points include speed, acceleration, kilometer marker position, and the most unfavorable safe braking distance. The data points are then fitted and connected to obtain the train's running curve. The formulas for calculating speed and kilometer marker position at each moment are as follows:

[0063]

[0064] In the formula:

[0065] v i For the present i The speed of time;

[0066] a i For the present i Acceleration at any moment;

[0067] s i For the present i The kilometer marker position at that moment;

[0068] △t The calculation period is the duration between adjacent moments, which can be understood as the resolution of each moment. It can be 100ms or 200ms, but cannot exceed 500ms, otherwise it will affect the accuracy of the final result.

[0069] S2: Using the ventilation shaft layout algorithm module, based on the determined tracking interval time requirements of the long tunnel section and the number of ventilation shafts set, the location of the ventilation shafts and the length of each ventilation shaft section are initially determined; the initial layout method refers to first dividing the long tunnel section according to the principle of equal division of the length, and it is necessary to ensure that the minimum length of each ventilation shaft section must be greater than the train length.

[0070] S3: Calculate the tracking interval time using the train tracking interval time algorithm module; verify whether each ventilation shaft section can meet the tracking interval time requirements. If it cannot meet the requirements, adjust the corresponding ventilation shaft positions and re-verify until the tracking interval time requirements are met; if the positions of some ventilation shafts in the middle are fixed by the designer and cannot be modified, the system will automatically adjust the positions of other ventilation shafts to meet the input tracking interval requirements.

[0071] like Figure 2 The diagram illustrates the method for calculating the tracking interval in long tunnel sections. During the tracking process between the preceding and following trains in the ventilation shaft section, it is necessary to ensure that when the rear of the preceding train leaves the current ventilation shaft section, the following train cannot possibly enter the ventilation shaft section of the preceding train, even under the most unfavorable circumstances. Assume that the moment the preceding train clears the exit of the current ventilation shaft section is T0. At this moment T0, the front of the following train is located at the most unfavorable safe braking distance from the entrance of the ventilation shaft section. The moment T1 at the most unfavorable safe braking distance is found through the train running curve. The calculation of the most unfavorable safe braking distance is referenced... Figure 5 As shown. Therefore, the tracking interval for this ventilation shaft section is equal to (T0 - T1).

[0072] The most unfavorable safe braking distance is determined based on the failure of the service brakes. The entire process of applying air brakes consists of three stages. The first stage is when the train outputs an uncontrolled acceleration due to a failure in the train's braking system after the braking command is issued. The second stage is when the train detects uncontrolled acceleration and switches to air brakes. During this stage, the traction / braking force output by the train is 0. The third stage is the entire emergency braking process of applying air brakes until the train stops.

[0073] The calculation method for the distance traveled during the first stage of uncontrolled acceleration is as follows:

[0074]

[0075] The second stage braking distance calculation method is as follows:

[0076]

[0077] The method for calculating the braking distance in the third stage is as follows:

[0078]

[0079] The entire most unfavorable safe braking distance is s = s 1 + s 2 + s 3 .

[0080] In the formula:

[0081] △t For the calculation period;

[0082] a runaway This represents the runaway acceleration value.

[0083] a grade This represents the acceleration value caused by the slope.

[0084] v 0 The initial speed at which the train begins emergency braking under the most unfavorable conditions;

[0085] t 1 The duration of the runaway acceleration during the first phase. t 1 =∑ △t ;

[0086] s 1 The first stage of uncontrolled acceleration covers a certain distance;

[0087] v 1 This is the speed at which the first stage of uncontrolled acceleration ends.

[0088] t 2 This refers to the duration of the runaway acceleration during the second phase. t 2 =∑ △t ;

[0089] s 2 The operating distance for switching to emergency braking in the second stage;

[0090] v 2 This is the speed value for switching to emergency braking in the second stage;

[0091] a eb This is the minimum guaranteed emergency braking rate for the train;

[0092] s 3 This refers to the emergency braking distance in the third stage.

[0093] The minimum length of each ventilation shaft section is greater than the length of the train.

[0094] S4: If the ventilation shaft layout meets the requirements, output the HMI interface. In this embodiment, the HMI module is primarily responsible for human-computer interaction with designers. This includes inputting and editing basic route data, vehicle data, etc. Based on the calculation results from other modules, it provides graphical displays, including real-time plotting and display of various curves for easy viewing and analysis by designers.

[0095] The ventilation shaft layout optimization design method in this embodiment can meet the throughput requirements of long tunnel sections, while also meeting the safety restriction that only one train can pass through each ventilation shaft section.

Claims

1. A method for optimizing the layout of ventilation shafts in long tunnel sections, characterized in that... The ventilation shaft layout optimization design method includes the following steps: S1: Calculate the train running curve in a long tunnel section; The calculation method for the train's running curve is as follows: The train's running curve in a long tunnel section is divided into four stages: the starting stage, the acceleration stage, the cruising stage, and the station braking stage. Data points for each moment in each of these stages are calculated and recorded. These data points include speed, acceleration, kilometer marker position, and the most unfavorable safe braking distance. The data points are then fitted and connected to obtain the train's running curve. The formulas for calculating speed and kilometer marker position at each moment are: ； In the formula: v i For the present i The speed of time; a i For the present i Acceleration at any moment; s i For the present i The kilometer marker position at that moment; △t The calculation period is the duration between adjacent moments. △t ≤500ms; S2: Based on the required number of ventilation shafts n, the long tunnel section is divided into equal sections according to the principle of length to preliminarily determine the layout of each ventilation shaft and the length of the ventilation shaft section; S3: Calculate the tracking interval time; verify whether each ventilation shaft section can meet the tracking interval time requirement. If it cannot meet the requirement, adjust the corresponding ventilation shaft position and re-verify until the tracking interval time requirement is met. The tracking interval is equal to T0-T1; where T0 is the time when the rear of the preceding train clears the exit of the current ventilation shaft section; at time T0, the front of the following train is located at the most unfavorable safe braking distance from the entrance of the ventilation shaft section, and the time T1 at the most unfavorable safe braking distance is found through the train operation curve. The calculation method for the most unfavorable safe braking distance is as follows: the braking distance of the train under the most unfavorable condition includes three stages; The calculation method for the distance traveled during the first stage of uncontrolled acceleration is as follows: ； The second stage braking distance calculation method is as follows: ； The method for calculating the braking distance in the third stage is as follows: ； The most unfavorable safe braking distance is s = s 1 + s 2 + s 3 ; In the formula: △t For the calculation period; a runaway This represents the runaway acceleration value. a grade This represents the acceleration value caused by the slope. v 0 The initial speed at which the train begins emergency braking under the most unfavorable conditions; t 1 The duration of the runaway acceleration during the first phase. t 1 =∑ △t ; s 1 The first stage of uncontrolled acceleration covers a certain distance; v 1 This is the speed at which the first stage of uncontrolled acceleration ends. t 2 This refers to the duration of the runaway acceleration during the second phase. t 2 =∑ △t ; s 2 The operating distance for switching to emergency braking in the second stage; v 2 This is the speed value for switching to emergency braking in the second stage; a eb This is the minimum guaranteed emergency braking rate for the train; s 3 This refers to the emergency braking distance in the third stage. The minimum length of each ventilation shaft section is greater than the length of the train.

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