A design method for a high-speed railway tunnel and a buffer structure

Abstract

The application provides a kind of global regulation high-speed railway tunnel, buffer structure design method, comprising: at the tunnel entrance, the rising time of initial compression wave is extended by buffer structure, so that the pressure rise is divided into two stages, and the pressure gradient amplitude is reduced;Pressure chamber is arranged in the tunnel, so that the compression wave oscillates in the pressure chamber several times, dissipates the energy of pressure wave to relieve the pressure wave and the pressure gradient amplitude;At the same time, local suction method can also be used on the inner wall of the tunnel to further reduce the intensity of the initial compression wave;At the tunnel exit, increase the buffer structure porosity, guide the airflow through the hole to dissipate energy outside, further relieve the micro-pressure wave amplitude at the tunnel exit.The application realizes effective relief of the alternating pressure amplitude in the tunnel and the micro-pressure wave at the tunnel exit by step-by-step energy dissipation at the tunnel entrance-tunnel-tunnel exit, meets the aerodynamic requirements of train rapid passing through the tunnel under multiple operating conditions, and at the same time can meet the demand of two-way driving.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-speed train tunnel aerodynamics, and particularly relates to a high-speed railway tunnel and buffer structure design method with global regulation. BACKGROUND

[0002] When the compression wave formed when the train enters the tunnel propagates to the tunnel exit at the speed of sound, part of it will suddenly expand in the form of a pulse to the outside of the tunnel, producing micro-pressure waves. Micro-pressure waves will produce intense explosive noise at the tunnel exit, which will adversely affect the surrounding environment and residents' lives. With the increase of train speed, especially when the high-speed maglev train reaches 600km / h, the fluctuation of tunnel pressure wave caused by the restriction of air flow space is more severe when the train enters the tunnel, and the amplitude of micro-pressure wave produced at the tunnel exit is larger.

[0003] Currently, the main method to alleviate the amplitude of micro-pressure wave is to set a buffer structure at the entrance of high-speed rail tunnel, enlarge the cross section of the tunnel exit or add a horizontal passage at the tunnel exit. These methods can have good effect on high-speed trains with a speed of 400km / h and below, but with the increase of train speed, especially when the high-speed maglev train reaches 600km / h, the amplitude of alternating pressure in the tunnel and the amplitude of micro-pressure wave at the tunnel exit will increase sharply, resulting in the failure of existing relief measures. Therefore, it is urgent to propose a new high-speed railway tunnel and buffer structure design method with global regulation, so as to greatly alleviate the amplitude of pressure wave in the high-speed railway tunnel and the amplitude of micro-pressure wave at the tunnel exit. SUMMARY

[0004] The purpose of the present application is to provide a high-speed railway tunnel and buffer structure design method with global regulation, which involves the positions of tunnel entrance, tunnel interior and tunnel exit, in view of the deficiencies in the background art.

[0005] In order to achieve the above purpose, the present application provides a high-speed railway tunnel and buffer structure design method with global regulation, comprising:

[0006] At the tunnel entrance, the rising time of the initial compression wave is prolonged by the buffer structure, so that the pressure rise is divided into two stages, and the amplitude of the pressure gradient is reduced;

[0007] In the tunnel interior, a pressure reduction cavity is provided, so that the pressure wave oscillates multiple times in the pressure reduction cavity, dissipates the energy of the pressure wave and thus relieves the amplitude of the pressure wave and the pressure gradient; and / or local suction is provided on the tunnel interior wall, when the initial compression wave is transmitted to the local suction, the suction is opened to reduce the air flow of the compression wave, further reducing the intensity of the initial compression wave, so as to slow down the amplitude of the initial compression wave, the pressure gradient and the micro-pressure wave at the tunnel exit;

[0008] At the tunnel exit, the open ratio of the buffer structure is increased, the airflow is guided to flow outwards through the holes to dissipate energy, and the amplitude of the micro-air pressure wave at the tunnel exit is further relieved.

[0009] Further, at the tunnel entrance, the buffer structure is set as a cross-section expansion type non-opening buffer structure.

[0010] Further, at the tunnel exit, the buffer structure is set as a cross-section expansion type opening buffer structure.

[0011] Further, the cross-section expansion type opening buffer structure is set as a gradually changing opening cross-section expansion type buffer structure, and the opening ratio gradually increases from the tunnel entrance end to the outer end.

[0012] Further, at both ends of the tunnel, the buffer structure is set as a gradually changing opening cross-section expansion type buffer structure, and the opening ratio gradually increases from the tunnel entrance end to the outer end.

[0013] Further, at both ends of the tunnel, the buffer structure is set as a cross-section expansion type buffer structure, and an opening with a switchable opening and closing state is arranged on the buffer structure, and when the train passes through the tunnel, the opening of the buffer structure at the tunnel entrance is closed, and the opening of the buffer structure at the tunnel exit is opened.

[0014] Further, the opening ratio of the buffer structure gradually increases from the tunnel entrance end to the outer end.

[0015] Further, an arched plate is arranged in the tunnel, a plurality of through holes are formed in the arched plate and are distributed along the length direction of the tunnel, a decompression cavity is formed between the arched plate and the tunnel wall after expansion, and one or more decompression cavities are arranged according to the length of the tunnel.

[0016] Further, an air suction section is arranged in the tunnel, one or more air suction sections are arranged according to the length of the tunnel, and the air suction speed direction is perpendicular to the wall surface.

[0017] The above-mentioned scheme of the present application has the following beneficial effects:

[0018] The full-range regulated high-speed railway tunnel and the buffer structure design method provided by the present application can realize effective relief of the amplitude of the alternating pressure in the tunnel and the micro-air pressure wave at the tunnel exit through classified and step-by-step energy dissipation. The relief measures at the tunnel entrance, in the tunnel and at the tunnel exit can be matched according to the train type, the train speed, the tunnel cross-section area, the buffer structure cross-section area, the buffer structure length, the opening ratio and the like, so as to meet the aerodynamic requirements of the train passing through the tunnel under multiple operation conditions, and at the same time, the bidirectional driving demand can be met.

[0019] Other beneficial effects of the present application will be described in detail in the following specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1This is a schematic diagram of the simulation model of the present invention;

[0021] Figure 2 This is a schematic diagram of the cross-sectional enlarged, hole-free buffer structure of the present invention;

[0022] Figure 3 This is a schematic diagram of the gradually enlarged opening cross-section buffer structure of the present invention;

[0023] Figure 4 This is a schematic diagram of the operation process of the maglev train of the present invention, wherein (a) is a schematic diagram of the running trajectory and the propagation of compression wave and expansion wave, and (b) is a curve of the tunnel wall pressure changing with time;

[0024] Figure 5 The time history curves of initial compression wave pressure and pressure gradient at the 1000m measuring point of this invention are shown (conditions 1-3).

[0025] Figure 6 The time history curves of initial compression wave pressure and pressure gradient at the 1000m measuring point of this invention are shown in the figure (conditions 2-4).

[0026] Figure 7 The time history curves of initial compression wave pressure and pressure gradient at a measuring point of 1000m under different buffer structures at the tunnel exit of the present invention (conditions 2-5);

[0027] Figure 8 This is a schematic diagram of the tunnel cavity structure of the present invention;

[0028] Figure 9 This is a front view of the cavity structure of the present invention;

[0029] Figure 10 This is a schematic diagram of the air intake section inside the tunnel according to the present invention. Detailed Implementation

[0030] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0031] It should be apparent that the aspects described herein can be embodied in a wide variety of forms and that any specific structure and / or function described herein is merely illustrative. Based on the teachings herein one skilled in the art should appreciate that an aspect described herein can be implemented independently of any other aspects and that an aspect described herein can be implemented both as any claim dependent on another and as an independent claim or claims. One skilled in the art should appreciate that an aspect described herein can be implemented as any element, combination of elements, or any combination of one or more elements and / or functions described herein.

[0032] It is also important to note that the use of the terms "preferably", "preferably", "more preferably", "most preferably" and the like are not always used consistently throughout. This is for the purpose of more clearly describing some embodiments together with various features and / or to avoid redundant restatements of preferred or appropriate aspects. However, it is intended that these terms be interpreted where appropriate by the persons skilled in the art in the light of the teachings and descriptions set forth herein.

[0033] The present application provides a global regulation method for high-speed railway tunnel and buffer structure design, which realizes effective relief of the amplitude of alternating pressure in the tunnel and the amplitude of micro-pressure wave at the tunnel exit through classification and step-by-step energy dissipation. The relief measures at the tunnel entrance, in the tunnel and at the tunnel exit can be matched according to the train type, train speed, tunnel cross-sectional area, buffer structure cross-sectional area, buffer structure length, opening rate and the like to meet the aerodynamic requirements of high-speed trains passing through the tunnel under multiple operation conditions.

[0034] In the embodiment, a high-speed maglev train with five carriages is used for numerical simulation. The height H of the maglev train is 4.2 m, the total length is 31.12H, the train width is 0.88H, the train cross-sectional area S train is 11.95 m 2 , the speed is 600 km / h, the track adopts a T-shaped track beam, the track surface is 1.25 m away from the ground, and the vertical distance between the bottom of the train and the upper surface of the tunnel beam is 0.02 m. In order to reflect the generation and propagation process of the initial compression wave and other basic information, a 2 km single-track tunnel is selected, the clearance area S t is 92 m 2 , the tunnel blockage ratio is 0.13, and the model schematic diagram is shown in Figure 1 .

[0035] Figure 2 A cross-sectional expansion type non-opening buffer structure (type I buffer structure) is set at the tunnel portal, and the cross-sectional area is S h= 2S t , the length L of the buffer structure h = 100 m. Figure 3 The gradual opening hole section expansion type buffer structure (type II buffer structure) is provided with openings on the top and side of the section expansion type buffer structure, and the opening rate is the ratio of the opening area to the inner wall area per unit length of the buffer structure. The opening mode is a gradual opening, and in this numerical simulation case, the opening rate of the buffer structure near the tunnel entrance end to the outer end increases uniformly from 10% to 50%, i.e. the opening rate changes every 20 m from the tunnel entrance end on the 100 m buffer structure. In other embodiments, the opening mode of the buffer structure can also be a linearly varying opening rate, or a segmented number, a segmented distance, a different opening rate for each segment, etc. This is not a limitation. The opening shape of the buffer structure is a square hole, which is uniformly distributed along the tunnel wall surface. In order to explore the characteristics of the initial compression wave and the micro-pressure wave under different buffer structure types at the tunnel entrance, the working conditions of this paper are listed in Table 1.

[0036] Table 1 Different buffer structure working conditions

[0037]

[0038] In order to analyze the pressure change in the tunnel when the maglev train passes through the tunnel, a large number of measuring points are arranged on the tunnel wall surface at a vertical height of 2.45 m (half the height of the car), 4.5 m (the height of the car), and 9.5 m (the top of the tunnel) at a distance of 50 m, 100 m, 140 m, 150 m, 300 m, 500 m, 800 m, 1000 m, 1200 m, 1500 m, 1800 m, 1900 m from the tunnel entrance along the length direction of the tunnel. In addition, in order to study the basic characteristics of the micro-pressure wave at the tunnel exit, a series of micro-pressure wave monitoring points are arranged at the same height of 2.45 m at a distance of 10 m, 20 m, 30 m, 40 m and 50 m from the tunnel exit.

[0039] Firstly, in order to study the waveform characteristics of the initial compression wave when it propagates in the tunnel, the characteristics of the initial compression wave generated when the maglev train enters the tunnel with type I buffer structure at both ends (working condition 2) and type II buffer structure at both ends (working condition 3) are analyzed. The waveform analysis of the initial compression wave is carried out by taking the measuring point at a distance of 150 m from the tunnel entrance as an example. The running track of the maglev train, the propagation diagram of the compression wave and the expansion wave, and the curve of the tunnel wall pressure change with time are shown in Figure 4 Figure 4 ​It can be seen that when t = 0.3s, the train head enters the buffer structure entrance, and the initial compression wave begins to form; t = 0.9s, the train head enters the tunnel entrance, and the second compression wave begins to form. The generated compression wave propagates at the speed of sound to the direction of the tunnel exit. When the initial compression wave reaches the 150m measuring point in the tunnel, compared with working condition 2, the first stage pressure rise of working condition 3 is not obvious. Because the pressure inside the buffer structure is higher than the pressure outside, there is a pressure difference between the two, so the gas inside the buffer structure will be discharged to the outside of the buffer structure through the square hole, that is, at the opening position of the buffer structure, the gas flows out through the hole to the outside, causing the "bleeding" phenomenon. Because the opening rate of the buffer structure closest to the exit end is 50%, the opening rate is large, and the gas bleeding is more, so the pressure rise of the first stage is not obvious. When the second stage compression wave reaches the 150m measuring point on the tunnel wall, the pressure rises rapidly.

[0040] Figure 5 The initial compression wave and the corresponding pressure gradient time history curve at a distance of 1000m from the tunnel entrance when the high-speed maglev train enters the tunnel entrance without a buffer structure (working condition 1), the tunnel ends with a type I buffer structure (working condition 2), and the tunnel ends with a type II buffer structure (working condition 3). It can be seen from the figure that: Figure 5 Compared with the buffer structure, the initial compression wave of the measuring point without the buffer structure is the steepest, and the corresponding pressure gradient amplitude is the largest. When the tunnel entrance is provided with a type I buffer structure (working condition 2), the initial compression wave pressure rise time of the measuring point and the pressure gradient peak value time are advanced. Mainly because 100m buffer structure is set at the tunnel entrance, the air in front of the train is compressed in advance, and the pressure rise is divided into two stages, so the pressure gradient appears two positive peaks: the first stage is when the train enters the buffer structure, the gas is disturbed, the pressure rises, and the pressure gradient appears the first peak. After the train enters the buffer structure for a certain distance, the disturbance of the gas flow begins to stabilize, and the pressure tends to be flat; the second stage is when the train enters the tunnel entrance, the cross-sectional area changes suddenly, the pressure rises, and the pressure gradient appears the second peak. Working condition 3 is to set a type II buffer structure at the tunnel entrance, and the square through hole is arranged along the direction of train running. During the train running, the air in front of the train is squeezed and the gas flow is discharged at the opening position of the buffer structure. The opening rate of the front end of the buffer structure in this embodiment is too large, and the train runs in the buffer structure like an open line, so the initial compression wave generated when the high-speed maglev train enters the buffer structure is too small, which leads to the pressure rise when the wave propagates to the measuring point is not obvious, and the first peak of the corresponding pressure gradient is not obvious, so the initial compression wave pressure amplitude and the pressure gradient amplitude are not significantly relieved.

[0041] Table 2 is the microbar wave amplitude of different measuring points at the outlet under different forms of buffer structure. From Table 2, it can be seen that the microbar wave amplitudes of the measuring points at the tunnel outlet 20 m and 50 m under working condition 3 are 140.2 Pa and 105.8 Pa respectively. Compared with working condition 2, although the initial compression wave pressure amplitude and the pressure gradient amplitude of working condition 3 are increased, the microbar wave amplitudes are reduced by 66.9% and 40.9% respectively; compared with working condition 1, the microbar wave amplitudes are reduced by 86.7% and 76.2% respectively, so the gradual opening cross-section expansion type buffer structure in working condition 3 can effectively reduce the microbar wave at the tunnel outlet.

[0042] Table 2 microbar wave amplitude of different measuring points

[0043]

[0044] In order to clarify the microbar wave relief mechanism at the tunnel outlet under working condition 3, working condition 4 is set, that is, the II type buffer structure is added at the tunnel inlet end, and the I type buffer structure is still used at the tunnel outlet end. Figure 6 The initial compression wave and the corresponding pressure gradient time history curves of the measuring points 1000 m away from the tunnel inlet under working condition 2 (both ends of the tunnel are I type buffer structure) and working condition 4 are compared, and working condition 3 (both ends of the tunnel are II type buffer structure) is introduced as a reference working condition. Working condition 2 and working condition 4 are different only in the buffer structure at the inlet end, and working condition 3 and working condition 4 are different only in the buffer structure at the outlet end. From Table 3, it can be seen that the initial compression wave and the corresponding pressure gradient time history curves of the measuring points 1000 m away from the tunnel inlet under working condition 3 and working condition 4 are basically the same, and the initial compression wave and the corresponding pressure gradient time history curves of the measuring points 1000 m away from the tunnel inlet under working condition 2 and working condition 4 are basically the same. Figure 6 It can be seen that the initial compression wave and the pressure gradient waveforms generated by the tunnel inlet end with and without the opening buffer structure are different. Without the opening buffer structure, the rising time of the pressure wave is effectively prolonged, so that the pressure rise is divided into two stages, and the pressure gradient amplitude is reduced. The II type buffer structure at the tunnel inlet under working condition 3 and working condition 4 has too large opening rate, so that the airflow is seriously discharged after the high-speed maglev train enters the buffer structure, resulting in that the pressure rise is not obvious when the train enters the buffer structure. Because the buffer structures at the tunnel inlet end of working condition 3 and working condition 4 are the same, the initial compression wave waveform and the corresponding pressure gradient waveform at the measuring points are basically the same, and it can be seen from Table 3 that the maximum initial compression wave pressure gradient values of the measuring points at different distances from the tunnel inlet under working condition 3 and working condition 4 are basically the same, and the maximum initial compression wave pressure gradient values at 100 m and 1900 m are 104.7 kPa / s and 191.5 kPa / s respectively. Compared with working condition 2, the maximum initial compression wave pressure gradient values are increased by 176.3% and 149.0% respectively. The initial compression wave pressure gradient values of working condition 3 and working condition 4 are all greater than that of working condition 2.

[0045] Table 3 maximum compression wave pressure value characteristics of the measuring points at different distances from the tunnel inlet end

[0046]

[0047] Table 4 is the micro-pressure wave amplitude of different distance measuring points outside the tunnel exit under working condition 2 and working condition 4, and working condition 3 is introduced as a reference working condition. From the table, it can be seen that: the micro-pressure wave amplitude of working condition 4 at the measuring points of 20m and 50m outside the tunnel exit is 758.5Pa and 306.3Pa respectively; the micro-pressure wave amplitude of working condition 2 at the measuring points of 20m and 50m outside the tunnel exit is 423.4Pa and 179.1Pa respectively; the micro-pressure wave amplitude of working condition 3 at the measuring points of 20m and 50m outside the tunnel exit is 140.2Pa and 105.8Pa respectively. Compared with working condition 2, the micro-pressure wave amplitude of working condition 4 increases by 79.1% and 71.0% respectively. Therefore, compared with no opening buffer structure, only setting the gradual opening cross-section expansion type buffer structure at the entrance end of the tunnel makes the maximum pressure value and the pressure gradient amplitude of the initial compression wave increase, thereby causing the micro-pressure wave amplitude at the tunnel exit to increase. Compared with working condition 3, although the maximum pressure gradient of the initial compression wave of working condition 4 is the same, the micro-pressure wave amplitude of working condition 4 at the measuring points of 20m and 50m outside the tunnel exit increases by 441.0% and 189.5% respectively, and the buffer structure types at the exit end of the two working conditions are different.

[0048] Table 4 micro-pressure wave amplitude of different measuring points

[0049]

[0050] Through analysis, it is found that when the opening rate of the buffer structure at the entrance end of the tunnel is too large, it will directly lead to the increase of the micro-pressure wave amplitude at the tunnel exit. Therefore, in order to further clarify the mechanism of the buffer structure, Figure 7 The initial compression wave and the corresponding pressure gradient time history curve of the measuring point 1000m away from the tunnel entrance under working condition 2 (both ends of the tunnel are type I buffer structure) and working condition 5 (the entrance end is type I buffer structure and the exit end is type II buffer structure) are compared, and working condition 3 (both ends of the tunnel are type II buffer structure) is introduced as a reference working condition. The buffer structure at the exit end of working condition 2 and working condition 5 is different. From Figure 7 It can be seen that: because the buffer structure at the entrance end of the tunnel under working condition 2 and working condition 5 is the same, the initial compression wave shape and the corresponding pressure gradient shape of the measuring point are basically coincided. The maximum pressure gradient value of the initial compression wave under working condition 2 and working condition 5 is less than that under working condition 3.

[0051] In order to clarify the mechanism of this difference, the airflow flow condition of the initial compression wave reaching the tunnel exit under different working conditions is simulated. Because the pressure inside the buffer structure is greater than the pressure outside, the airflow will flow to the outside through the square hole, thereby causing the airflow to leak, and the energy of the initial compression wave to dissipate, and the strength to weaken, so the gradual opening cross-section expansion type buffer structure at the exit end can effectively slow down the micro-pressure wave amplitude.

[0052] Table 5 is the micro-pressure wave amplitude of the measuring points at different distances from the tunnel exit under working conditions 2 and 5, and working condition 3 is taken as a reference. As can be seen from Table 5, the micro-pressure wave amplitude of working condition 5 at the measuring points 20 m and 50 m from the tunnel exit is 67.7 Pa and 51.7 Pa respectively; and the micro-pressure wave amplitude of working condition 2 at the measuring points 20 m and 50 m from the tunnel exit is 423.4 Pa and 179.1 Pa respectively. Compared with working condition 2, the micro-pressure wave amplitude of working condition 5 is reduced by 84.0% and 71.1% respectively. Under the condition that the buffer structure at the entrance end is the same, the gradual opening cross-section expansion type buffer structure at the tunnel exit can effectively reduce the micro-pressure wave amplitude. Compared with working condition 3, the micro-pressure wave amplitude of working condition 5 at the measuring point 20 m from the tunnel exit is reduced by 51.7% and 51.1% respectively. Therefore, the non-uniform buffer structure design method at both ends of the tunnel portal can further alleviate the micro-pressure wave amplitude at the tunnel exit.

[0053] Table 5 is the micro-pressure wave amplitude of the measuring points at different distances from the tunnel exit under working conditions 2 and 5, and working condition 3 is taken as a reference. As can be seen from Table 5, the micro-pressure wave amplitude of working condition 5 at the measuring points 20 m and 50 m from the tunnel exit is 67.7 Pa and 51.7 Pa respectively; and the micro-pressure wave amplitude of working condition 2 at the measuring points 20 m and 50 m from the tunnel exit is 423.4 Pa and 179.1 Pa respectively. Compared with working condition 2, the micro-pressure wave amplitude of working condition 5 is reduced by 84.0% and 71.1% respectively. Under the condition that the buffer structure at the entrance end is the same, the gradual opening cross-section expansion type buffer structure at the tunnel exit can effectively reduce the micro-pressure wave amplitude. Compared with working condition 3, the micro-pressure wave amplitude of working condition 5 at the measuring point 20 m from the tunnel exit is reduced by 51.7% and 51.1% respectively. Therefore, the non-uniform buffer structure design method at both ends of the tunnel portal can further alleviate the micro-pressure wave amplitude at the tunnel exit.

[0054]

[0055] From the above, it can be concluded that:

[0056] When the gradual opening cross-section expansion type buffer structure is used at both ends of the tunnel, the micro-pressure wave amplitude at the tunnel exit can be effectively reduced. The micro-pressure wave amplitude at the measuring point 20 m from the tunnel exit is 140.2 Pa, which is reduced by 66.9% compared with the condition that the cross-section expansion type buffer structure without opening is used at both ends of the tunnel, and is reduced by 86.7% compared with the condition that no buffer structure is used.

[0057] When the gradual opening cross-section expansion type buffer structure is used at the entrance end of the tunnel, due to the large opening rate, the "flow leakage" phenomenon occurs after the high-speed maglev train enters the buffer structure, which causes the pressure rise of the train when entering the buffer structure to be not obvious, and thus the maximum pressure value and the pressure gradient of the initial compression wave are increased. When the gradual opening cross-section expansion type buffer structure is used at the entrance end of the tunnel and the cross-section expansion type buffer structure without opening is used at the exit end of the tunnel, the micro-pressure wave amplitude at the measuring point 20 m from the tunnel exit is 758.5 Pa, which is increased by 79.1% compared with the condition that the cross-section expansion type buffer structure without opening is used at both ends of the tunnel.

[0058] When the tunnel exit is a gradual opening section expansion type buffer structure, the internal pressure of the buffer structure is greater than the external pressure, and the airflow flows to the outside through the square hole under the action of the pressure difference. Compared with the buffer structure without an opening, the initial compression wave is weakened after the airflow leaks, and the micro-pressure wave intensity generated at the port is weakened. When the tunnel exit end is a gradual opening section expansion type and the entrance end is a section expansion type buffer structure without an opening, the micro-pressure wave amplitudes at a distance of 20 m and 50 m from the tunnel exit are 67.7 Pa and 51.7 Pa, respectively. Compared with the section expansion type buffer structure without an opening at both ends, the micro-pressure wave amplitudes are reduced by 84.0% and 71.1%, respectively.

[0059] Therefore, based on the purpose of bidirectional driving of the train, the same type of buffer structure is arranged at both ends of the tunnel portal, which can achieve good micro-pressure wave relief effect, and the gradual opening section expansion type buffer structure at both ends is better than the section expansion type buffer structure without an opening at both ends. However, with the increase of the speed of the train, the micro-pressure wave amplitude presents an exponential growth. In order to further improve the micro-pressure wave relief effect and reduce the harm caused by the micro-pressure wave, a non-uniform type is used at both ends of the tunnel portal, which can be adjusted and switched according to the driving direction of the train, that is, the tunnel entrance end is switched to a section expansion type buffer structure without an opening, and the tunnel exit end is switched to a gradual opening section expansion type buffer structure. When driving in the opposite direction, the buffer structure forms at both ends is switched, which can further relieve the micro-pressure wave amplitude at the tunnel exit and achieve the best overall relief effect.

[0060] In addition, based on the foregoing analysis, when the initial compression wave propagates into the tunnel, the pressure will rapidly rise. Therefore, in order to further improve the relief effect, one or more pressure relief cavities can be arranged inside the intensification point tunnel, so that the pressure wave oscillates multiple times in the pressure relief cavity, dissipates the energy of the pressure wave, and further relieves the amplitude of the pressure wave and the pressure gradient.

[0061] The embodiment further adds an arched plate in the tunnel on the basis of the working condition 5. A plurality of through holes are arranged on the arched plate and distributed along the length direction of the tunnel, so that a pressure relief cavity is formed between the arched plate and the tunnel wall. The thickness of the arched plate is 0.26 m. The through holes are arranged in three rows along the axial direction of the arched plate and are distributed on the left side, the right side and the top of the arched plate. The through holes in each row are arranged symmetrically on the cross section of the arched plate. The through holes in the same row are arranged at equal distances along the axial direction of the arched plate, and the distance between the holes is 5 m. There are 19 square holes with a size of 4 m*4 m in each row, as shown in Figs. 5 and 6. Figure 8 、 Figure 9

[0062] ​Further demonstrated by numerical simulation, compared with the working condition 5 without setting the arched plate, the micro-pressure wave amplitude at the measuring points 20 m and 50 m at the tunnel exit is 53.9 Pa and 42.3 Pa respectively, and the weakening effect is 20.3% and 18.1% respectively. Compared with the working condition 2 without setting the arched plate, the micro-pressure wave amplitude at the measuring points 20 m and 50 m at the tunnel exit is reduced by 87.2% and 76.3% respectively.

[0063] Table 6 Micro-pressure wave amplitude at different measuring points at the tunnel exit

[0064]

[0065] In addition, based on the foregoing analysis, when the initial compression wave reaches the measuring point in the tunnel, the pressure will rise rapidly. Therefore, in order to further improve the mitigation effect, a local air suction mode can also be used on the inner wall of the tunnel. When the initial compression wave reaches the place, the air suction is started to reduce the air flow of the compression wave and further reduce the intensity of the initial compression wave, so as to slow down the amplitude of the initial compression wave, the pressure gradient and the micro-pressure wave at the tunnel exit, as shown in Figure 10

[0066] In this embodiment, an air suction structure is additionally arranged in the tunnel without a buffer structure. The air suction structure is located at a position one vehicle length away from the tunnel entrance (i.e. 130.7 m away from the tunnel entrance), and the boundary condition is defined as a velocity inlet. The air suction is performed at a speed of 50 m / s and vertically to the tunnel section. The micro-pressure wave under the action of the air suction structure is compared with that without the buffer structure, as shown in Table 6. The main conclusions are as follows: when the air suction structure is added in the tunnel, the micro-pressure wave amplitude at the tunnel exit can be effectively slowed down. The micro-pressure wave amplitude at the measuring point 20 m at the tunnel exit is 571 Pa, which is 45.5% slower than 1048 Pa at the measuring point 20 m at the tunnel exit without the air suction structure.

[0067] Table 7 Micro-pressure wave at the tunnel exit with the air suction structure and without the air suction structure

[0068]

[0069] ​In summary, in combination with train type, train speed, tunnel cross-sectional area, buffer structure cross-sectional area, buffer structure length, and opening rate, a smooth pressure gradient model is established at the tunnel entrance position, the initial compression wave pressure is maximized by the buffer structure at the tunnel entrance position, and the optimal mitigation of the aerodynamic effect of the tunnel entrance is ensured. Inside the tunnel, a pressure relief chamber is provided, so that the pressure wave oscillates multiple times in the pressure relief chamber, dissipates the pressure wave energy, and / or a local air suction method is used on the inner wall of the tunnel, when the initial compression wave is transmitted to this place, the air suction is opened, the air flow of the compression wave is reduced, so as to further mitigate the pressure wave and the pressure gradient amplitude. When the pressure wave is transmitted to the tunnel outlet, the opening rate of the buffer structure is gradually increased, the airflow is guided to flow to the outside through the hole, the "bleeding" phenomenon occurs, the energy is further dissipated, and finally the initial compression wave and the pressure gradient amplitude of the high-speed railway tunnel and the outlet micro-pressure wave amplitude are greatly mitigated.

[0070] The above is the preferred embodiment of the present application, it should be pointed out that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A design method for high-speed railway tunnels and buffer structures with full-domain control, characterized in that, include: At the tunnel entrance, a buffer structure is used to extend the rise time of the initial compression wave, so that the pressure rise is divided into two stages, thereby reducing the pressure gradient amplitude. Inside the tunnel, a pressure relief chamber is set up so that the compression wave oscillates multiple times within the chamber, dissipating the pressure wave energy; and / or local air intake is provided on the tunnel wall. When the initial compression wave reaches the local air intake point, the air intake is activated to reduce the air flow of the compression wave and decrease the intensity of the initial compression wave. At the tunnel exit, the permeability of the buffer structure is increased to guide the airflow through the holes to dissipate energy to the outside and alleviate the amplitude of the micro-pressure wave at the tunnel exit. At the tunnel entrance, a buffer structure with an enlarged cross-section and no openings is installed. At the tunnel exit, a buffer structure with an enlarged cross-section and an open-type buffer structure is installed. The cross-section enlarged opening buffer structure is set as a gradually increasing opening cross-section enlarged buffer structure, with the opening ratio gradually increasing from the end near the tunnel entrance to the outer end, uniformly increasing from 10% to 50%; The tunnel is a single-track tunnel, designed for bidirectional train travel. The buffer structure is equipped with openings that can be switched between open and closed states. The buffer structure is adjusted and switched according to the train's direction of travel. When a train passes through the tunnel, the openings of the buffer structure at the tunnel entrance are closed, and the openings of the buffer structure at the tunnel exit are open.

2. The design method for high-speed railway tunnels and buffer structures with full-domain control according to claim 1, characterized in that, An arched plate is installed inside the tunnel, with multiple through holes distributed along the length of the tunnel. A pressure relief cavity is formed between the arched plate and the tunnel wall after widening. One or more pressure relief cavities are set according to the length of the tunnel.

3. The design method for high-speed railway tunnels and buffer structures with full-domain control according to claim 1, characterized in that, An air intake section is set up inside the tunnel. One or more air intake sections are set up according to the length of the tunnel, and the air intake speed direction is perpendicular to the wall.

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