WO2003080997A1

WO2003080997A1 - Buffer plate

Info

Publication number: WO2003080997A1
Application number: PCT/JP2003/003559
Authority: WO
Inventors: Mikio Yamazaki; Masashi Suzuki; Satoru Kato; Takanobu Ogawa; Toshihiro Wakahara; Toshimitsu Tanaka
Original assignee: Central Japan Railway Company
Priority date: 2002-03-26
Filing date: 2003-03-24
Publication date: 2003-10-02
Also published as: JP4220716B2; TW200304522A; JP2003278488A

Abstract

A tunnel buffer plate (11) capable of eliminating or suppressing low frequency aerial vibration produced when a high speed vehicle rushes into and exits a tunnel, comprising a plurality of pressure loss holes (30) for regulating the pressure loss of the pressure wave produced between a high speed railcar rushing into or exiting the tunnel and a cover body (10), wherein the pressure loss holes (30) are disposed so that the quantity thereof is gradually reduced starting at one end of the cover body (10) toward the other end, whereby an intermediate state for providing a proper pressure loss can be formed between a light district and a tunnel district and an effect as if the high speed vehicle gradually rushes into the tunnel can be created, i.e., a variation in pressure gradient of the pressure wave can be made smooth and, as a result, the occurrence of the low frequency air vibration by the rushing wave or exiting wave of the high speed railcar can be eliminated or suppressed and the problem of rattling of the fittings of private houses near the tunnel can be solved.

Description

Description Buffer

The present invention relates to a shock absorber connected to an entrance and exit of a tunnel structure, and more particularly, to a shock absorber capable of eliminating or suppressing low-frequency air vibration generated by pressure waves generated when a high-speed vehicle enters and exits a tunnel structure. <Background Technology

As shown in Fig. 8A, when the head of a railway vehicle enters a tunnel, a compression wave is formed in the tunnel. This compression wave propagates through the tunnel at the speed of sound while increasing its pressure gradient, and when it reaches the opposite wellhead (exit), it is emitted as a pulse-like pressure wave from this wellhead. This pressure wave is called a micro-pressure wave and emits a sound called “dawn” when radiated from the wellhead. Therefore, measures have been considered as one of the environmental problems of high-speed railways. Then, since it was found that the level of the micro-pressure wave was almost proportional to the pressure gradient of the pressure wave that reached the tunnel exit, one of the countermeasures against the micro-pressure wave was that no sound was generated at the tunnel exit side. The pressure gradient formed at the entrance of the tunnel was reduced in advance.

Specifically, as a countermeasure on the ground side, a tunnel buffer consisting of a cover larger than the tunnel section is installed at the tunnel entrance side, side windows are formed at regular intervals on the side walls, and Measures were taken to reduce the pressure gradient of the pressure wave formed at the tunnel inlet by adjusting the opening amount. By installing a tunnel buffer with this configuration, Some achievements were made on the problem of reducing the sound emission at the exit side.However, when the train entered the tunnel at high speed, not only the above-mentioned problems at the tunnel exit side due to the micro-pressure wave but also the tunnel entrance The problem of so-called low-frequency air vibration occurs due to the rush wave (low frequency) generated on the side.

This low-frequency air vibration is a pulse-like pressure wave (rush wave) that is generated when a high-speed railway moves from a light section (outside the tunnel) to a tunnel section due to a change in cross-section of a structure near the train. This is a vibration phenomenon that occurs when radiation is emitted from the entrance of the tunnel to the surrounding area. This problem of low-frequency air vibration is particularly prominent in high-speed railways such as linear motor cars. If this low-frequency air vibration propagates along railway lines, it causes rattling of fittings in private houses around the tunnel. As shown in Fig. 8B, this low-frequency air vibration is also generated at the exit of the tunnel due to the exit wave (low frequency) generated when the train exits the tunnel at high speed.

Therefore, as a countermeasure for reducing the low frequency, conventionally, a buffer opening of the tunnel buffer was enlarged so as to have an enlarged shape, and an opening amount of a side window of the tunnel buffer was adjusted. . Specifically, in order to mitigate the change in cross section between the tunnel buffer and the tunnel, the ceiling on the open side of the tunnel buffer (the side opposite to the connection with the tunnel) is cut off in a V-shape, or the tunnel buffer is cut off. The approach was to reduce the opening of the side window toward the tunnel entrance.

However, even if such notches and side windows are provided, air vibration is generated due to the sudden pressure increase when the train passes through the side window after passing through the end of such V-shaped notch. Therefore, the above measures did not solve the problem drastically. Disclosure of the invention Therefore, an object of the present invention is to provide a tunnel buffer capable of eliminating or suppressing low-frequency air vibration generated when a high-speed vehicle enters and exits a tunnel.

In view of the above problems, the shock absorber of the present invention has an elongate cover having an open portion at one end and the other end connected to the entrance of the tunnel structure, and a plurality of the cover is provided on the wall surface of the cover, The vehicle is provided with a pressure loss hole for adjusting a pressure loss of a pressure wave generated between a high speed vehicle that attempts to enter or exit the tunnel structure and the cover. A plurality of the pressure loss holes are provided in the circumferential direction (that is, a direction perpendicular to the longitudinal direction of the cover) in the vicinity of one end of the cover, and gradually decrease from one end to the other end of the cover. It is arranged in. The “tunnel structure” here includes not only a general tunnel but also a tunnel-like structure (a hood-like structure) (hereinafter, these are simply referred to as Γ tunnels).

The “pressure loss hole” here is a hole having an opening smaller than that of the side window generally seen in the above-described conventional technology, and is an effective pressure of a pressure wave generated between the high-speed vehicle and the cover. Loss can be expected. In other words, in the conventional side window, this pressure wave is released to the outside without giving a significant pressure loss, but in this buffer, the `` pressure loss hole '' with a certain level of pressure loss is provided. A relatively large number is provided, each of which suppresses rapid fluctuations in pressure waves. A relatively large number of the “pressure loss holes” are provided in the circumferential direction (or width direction) near one end of the cover, and the number thereof is increased toward the other end along the longitudinal direction of the cover. It is gradually decreasing.

That is, for example, when a high-speed vehicle enters a tunnel, the pressure loss and the pressure gradient are substantially zero in front of the cover without a wall surface (light section), whereas the pressure loss in the tunnel section with a wall surface is substantially zero. Theoretically becomes infinite, and the pressure gradient rises sharply at the entrance. So this In order to mitigate the change in pressure gradient between the light section and the tunnel section, an intermediate state where moderate pressure loss is provided by a tunnel buffer with multiple pressure loss holes is formed, It creates the effect of entering or exiting a tunnel.

Then, in order to gradually change the intermediate state and smoothly connect the light section and the tunnel section, first, a relatively large number of pressure loss holes are arranged near the opening of the cover to reduce the pressure loss relatively. It is made smaller, and the steep rise of the pressure gradient of the pressure wave (rush wave) suppresses the rise. The pressure loss is gradually increased by gradually reducing the pressure loss hole toward the tunnel entrance, thereby preventing a sudden change in the pressure gradient at the tunnel entrance. In other words, by gradually reducing the pressure loss hole from the open side of the cover toward the tunnel entrance, the pressure loss of the pressure wave generated between the high-speed vehicle and the cover is gradually increased, The change in the pressure gradient is smoothed toward the tunnel entrance. When a high-speed vehicle exits the tunnel, the pressure drop holes gradually increase from the tunnel entrance to the opening of the tunnel buffer. The pressure loss of the pressure wave generated between and gradually decreases, but the same is true in that the change in the pressure gradient is smoothed.

With this configuration, it is possible to obtain the same effect as reducing the cross-sectional change of the structure when the high-speed vehicle enters or exits the tunnel. Generation of low-frequency air vibration can be eliminated or suppressed. In other words, it is possible to solve the problem of rattling of the fittings of a private house around the tunnel due to low-frequency air vibration generated when a high-speed vehicle enters or exits the tunnel at a high speed.

Such a buffer, when configured as, for example, a tunnel buffer for a high-speed railway, exhibits its effect particularly remarkably. High-speed train runs through a tunnel This is because, among high-speed vehicles, the speed is particularly high, and the higher the speed, the greater the pressure energy around the vehicle, and the lower frequency air vibration is likely to affect the area around the tunnel entrance. This problem is considered to be particularly prominent in a high-speed railway such as a linear motor car with a traveling speed of about 500 km_h, so the effect of the present invention is particularly remarkably exhibited. Become.

At this time, the opening ratio of the cover wall surface due to the pressure loss hole is formed to be 10 to 20% at the extreme end near the one end, and is gradually reduced toward the other end. It is effective. This is because, as described in the embodiments described later, when the aperture ratio is set as described above, the effect of suppressing low-frequency air vibration is particularly effectively exerted.

Further, it is desirable that the pressure loss hole is formed from near one end to near the other end of the cover. Experimental results have shown that the effect of reducing the sound generated at the tunnel exit side by the above-mentioned micro-pressure wave can be enhanced by maintaining the opening ratio in the vicinity of the tunnel entrance and exit of the cover at a low rate. Because.

According to this configuration, the problem of low-frequency air vibration can be solved at one end of the cover, and the problem due to the micro-pressure wave can be simultaneously solved at the other end, and the pressure loss hole is provided at the other end. Since it has a configuration that is gradually reduced toward the end, both effects can be continuously and smoothly exerted.

Specifically, the opening ratio of a portion of the cover from the tunnel entrance (for example, a portion from the center of the cover to the vicinity of the tunnel entrance) is about 1% (preferably 0.8% to 0.9%). Experimental results show that if the pressure is maintained at, the effect of reducing the sound generated by the micro-pressure wave at the exit of the tunnel will increase. Further, in order to obtain an effective pressure loss at each pressure loss hole, the Reynolds number of the airflow passing through the pressure loss hole needs to be a certain value or more (100 or more). Experimental results show that the pressure loss coefficient becomes constant when the Reynolds number becomes constant.

For this reason, it is preferable that the pressure loss hole be formed so that the hole diameter or the hole width is such that the individual pressure loss coefficient at each pressure loss hole when the high-speed vehicle passes through the cover is substantially constant.

However, if the pressure loss hole is too large, there is a concern that the pressure wave radiated from the pressure loss hole will increase.For example, in the case of high-speed railways, the hole diameter or hole width of the pressure loss hole is the average cross section of the vehicle. It is desirable to be about 1/10 or less of the scale.

In consideration of such circumstances, the buffer for high-speed railway is preferably formed so that the hole diameter or hole width of the pressure loss hole is about 10 mm or more and 100 mm or less.

This is because it is considered that a hole diameter or hole width of about 10 mm is enough to secure the Reynolds number for the buffer for high-speed railway. Further, the preferable pressure loss is almost determined by the ratio between the thickness of the wall of the cover and the size of the pressure drop hole (hole diameter or hole width). However, the thickness of the wall of the cover must be reduced, and in this case, the strength of the cover cannot sufficiently withstand the fluctuating pressure when a vehicle passes. Also, when the hole diameter or the hole width is small, a so-called “whistle” sound is easily generated, which causes a problem of noise. On the other hand, if it is larger than 100 O mm, the pressure wave radiated from the pressure loss hole becomes large.

However, when the hole diameter or the hole width is small, it is necessary to form a large number of pressure loss holes, and thus there is a problem that the processing cost of the buffer increases. Conversely, if the hole diameter or hole width is large, especially when the pressure loss hole is provided on the upper wall of the cover, an operator throws an object into the pressure loss hole or works on the cover. There is a concern that problems such as falling accidents may occur. For this reason, it is preferable that the hole diameter or the hole width is formed to be about 100 mm or more and about 300 mm or less.

It has also been found that the whistle sound of the pressure drop hole is greatly affected by the shape of the peripheral edge. In particular, when the cover is made of a steel plate or the like, it may occur due to remaining burrs at the time of forming the pressure drop hole.

Therefore, it is preferable that the peripheral edge of the pressure loss hole is chamfered because such a problem can be avoided.

Further, the buffer may include an enclosing wall connected to one end of the cover, and the enclosing wall may be formed such that the side wall gradually increases from the roadbed surface toward one end of the cover. The technology for providing such an enclosing wall is a known technology, but by combining with the configuration of the present invention, a remarkable effect that has not been achieved in the past can be exhibited.

That is, in such a configuration, for example, when a railway vehicle tries to enter a tunnel, the surrounding wall is gradually enlarged, so that the pressure gradient of the pressure wave between the railway vehicle and the surrounding wall can be gradually increased. it can. When the railway vehicle reaches the cover, a suitable pressure loss is applied to the pressure loss hole, and the pressure gradient of the pressure wave can be smoothly increased to reach the tunnel section. As a result, the change in the pressure gradient between the clear section and the tunnel section can be further reduced, and low-frequency air vibration can be more effectively eliminated or suppressed.

However, at this time, if the pressure loss holes are also distributed on the side wall of the cover, the pressure loss holes will appear suddenly continuously on the surrounding wall where the holes are not provided, and the pressure distribution due to the pressure wave will be disturbed. This may cause noise and vibration.

Therefore, in the case where an enclosure wall having no hole is provided, it is preferable that the pressure loss hole is provided mainly in the upper wall of the cover. According to such a configuration, since the space above the surrounding wall gradually narrows toward the cover, the pressure loss hole is provided in the upper wall, so that the space becomes smaller continuously. It can create a situation that is becoming increasingly aerodynamic and can be connected very smoothly. As a result, generation of low-frequency air vibration can be more effectively eliminated or suppressed.

In addition, by providing a pressure drop hole in the upper wall, even if some air vibration remains, the air vibration can be reduced due to its diffraction effect, and the running noise of high-speed vehicles can be further reduced. Can be. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view showing a schematic configuration of a buffer according to an embodiment of the present invention.

2A, 2B, and 2C are explanatory diagrams showing the configuration of the tunnel buffer according to the embodiment.

FIG. 3 is an explanatory diagram showing the analysis conditions of the numerical analysis performed to construct the tunnel buffer of the embodiment.

FIG. 4 is a graph showing the results of the numerical analysis of FIG.

FIG. 5 is an explanatory view of a model according to a model experiment performed to construct the tunnel buffer of the embodiment.

FIG. 6 is an explanatory diagram of a model according to a model experiment performed to construct the tunnel buffer of the embodiment.

7A, 7B, 7C, and 7D are graphs showing the results of the model experiment, and

8A and 8B are explanatory diagrams showing the problems of the conventional technology. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In this embodiment, the buffer of the present invention is constructed in a tunnel buffer of a high-speed railway.

FIG. 1 is a perspective view showing a schematic configuration of the tunnel buffer.

As shown in Fig. 1, the tunnel buffer 1 is composed of a long cover 10 having a total length of about 100 m, a width of about 14 m, and a height of about 7 m. 1 O a and the other end is connected to the entrance of tunnel T.

As shown in the plan view of the tunnel buffer 1 in FIG. 2A, the cover 10 is composed of a rectangular frame-shaped frame formed by connecting a plurality of H-shaped steels (not shown) in a grid pattern. And a PC board (prestress concrete board) 22.

As shown in FIG. 2B, the steel plate 21 has a rectangular main body having a length L 約 of about 2 m, a width W 1 of about 1 m, and a thickness t 1 of about 9 mm. A plurality of pressure loss holes 30 penetrating in the direction are provided. The pressure loss hole 30 is formed by a pressure generated between a high-speed railway vehicle (linear motor car: not shown in this embodiment: not shown) entering the tunnel T or leaving the tunnel T and the cover 10. It is a hole for giving a suitable pressure loss to waves. In this embodiment, the pressure loss hole 30 is formed as a circular hole having a diameter of 100 mm, and a peripheral edge thereof is chamfered (not shown) to prevent a so-called whistle sound.

However, there are a plurality of steel plates 21 having different numbers of pressure loss holes 30 (in the present embodiment, a maximum of 32 and a minimum of 2) due to the setting of the aperture ratio described later.

On the other hand, as shown in FIG. 2C, the PC board 22 has a rectangular main body having a length L2 of about 2 m, a width W2 of about 1 m, and a thickness t2 of about 70 mm.

Then, as shown in FIG. 2A, the upper wall 11 of the cover 10 is formed by a plurality of steel plates 21 (scattered patterns in the figure) and PC boards 22 (no patterns in the figure) in a fixed manner. The side walls 12 of the cover 10 are P Only the C plate 22 is arranged without a plurality of gaps. Therefore, in this embodiment, only the upper wall 11 of the tunnel buffer 1 has a porous structure. Further, the steel plate 21 and the PC plate 22 are selectively arranged such that the pressure loss hole 30 gradually decreases from the open portion 10a side of the cover 10 toward the entrance and exit of the tunnel T.

In this embodiment, a fixed area (about 14 m) at the end of the tunnel buffer 1 on the side of the tunnel entrance is a step-eliminated section, and no pressure loss hole 30 is provided.

Next, evaluation of the arrangement of the pressure loss holes provided in the cover will be described. In other words, the inventors have verified by numerical analysis and model experiments the arrangement of the pressure drop holes suitable for countermeasures against low-frequency air vibration generated when a high-speed vehicle enters and exits a tunnel. Hereinafter, these results will be described.

[Numerical analysis results]

First, a plurality of holes (pressure loss holes) were provided on the wall surface of the cover of the tunnel buffer, and the holes were gradually reduced from one end of the cover (buffer erotic: open side) to the other end (the tunnel entrance side). Assuming a case, a numerical analysis was performed on the relationship between the aperture ratio distribution on the wall surface of the cover of the tunnel buffer and the pressure wave reduction effect. Specifically, as a tunnel buffer having an opening ratio distribution in which the opening ratio of the cover gradually decreases, a plurality of patterns with different opening ratios at the extreme end near the buffer erotic are set, and a high-speed railway vehicle is set for each of them. We analyzed the pressure fluctuations of the rush wave (pressure wave) when rushing. FIG. 3 is an explanatory diagram showing the analysis conditions of the numerical analysis, and FIG. 4 is a graph showing the analysis results.

As shown in the conceptual diagram of a high-speed railway vehicle viewed from above in Fig. 3, the numerical analysis simulates the eccentric running of a high-speed railway vehicle, where the diameter of the tunnel is D, and the total length of the tunnel buffer is L (= 25.0 D), buffer the evaluation point of air vibration. 5.0 D from the high-speed railway car running eccentrically at the entrance. The running speed of the high-speed railway vehicle was set at 500 km / h. Then, the length of the porous wall where the pressure loss holes are arranged is L p (= L / 2 = 12.5 D) from the buffer inlet, and four types of porous walls with different aperture ratio distributions are set. did.

In other words, as shown in the lower part of Fig. 3, a graph showing the relationship between the opening ratio distribution and the distance from the buffer inlet, the aperture ratio in the vicinity of the inlet of the buffer is 8) and the porous wall with 14.1% (thick solid line) Numerical analysis was performed for a 28.2% porous wall (1) (dashed line), a 42.3% porous wall (3) (dotted line), and a 7.05% porous wall (1) (dotted line). The horizontal axis of the graph represents the dimensionless distance that represents the distance X from the buffer inlet to the length LP of the porous wall, and the vertical axis represents the aperture ratio at the dimensionless distance. Each of these perforated walls is set so that the opening ratio gradually decreases from the buffer entrance to the tunnel entrance (exit), and the center of the tunnel buffer (X = L p == 1/2 L ) Is set so that the opening rate becomes zero.

Figure 4 shows the time-series data of the pressure fluctuation of the pressure wave when it is assumed that the high-speed railway vehicle is traveling 0.2 D eccentrically (traveling 0.2 D from the center of the tunnel buffer). Represents. The evaluation point is 5.0 D from the high-speed railcar at the buffer entrance position (X = 0.0 D) as described above. The horizontal axis represents the measurement time (s) when the time at which the tip of the high-speed railcar passes through the buffer entrance is 0.0 (s), and the vertical axis represents the pressure fluctuation at the measurement time. In addition, this analysis was also performed in the case where no pressure drop hole was provided (no opening: thin solid line) as a comparative example, in addition to the porous walls 1 to 5 described above. Note that there is a negative value for the time (s), which means that the pressure fluctuation is analyzed before the high-speed railway vehicle enters the tunnel buffer. As can be seen from these figures, in each case, there is a negative pressure peak near time 0.1 (s) and a positive pressure near time 0.5 (s). Since these peak values (amplitude) mean the magnitude (intensity) of the pressure wave, focusing on the peak values, the porous wall ① (j8 = 14.1), the porous wall Wall ② (= 28.2), perforated wall ③ (j8 = 42.3), perforated wall ④ () 8 = 7.05), no aperture (] 8 = 0.0) . Therefore, it was found that the maximum pressure reduction effect was obtained when the opening ratio near the buffer inlet was in the range of 10 to 20%.

[Model test results]

Subsequently, a model experiment was performed based on the results of the above numerical analysis. The upper part of FIG. 5 is a plan view showing the model M of the tunnel buffer, the right part is a sectional view, and the lower part is a side view.

This model M is about 134 models of the actual tunnel buffer 1 and was created by processing a steel plate. The total length L of the cover M 1 of the model M is 2941 mm, and the length L p of the porous wall portion provided with the pressure loss hole (indicated by a point in the figure) is 1 from the buffer inlet. It is formed to be 470 mm (= 1/2 L). The cross section is larger than the cross section of the tunnel model t (diameter D), and has a width W of 440 mm and a height H of 220 mm. A track R is eccentrically laid to one side on the left and right sides from the tunnel buffer to the inside of the tunnel t, and a high-speed railway model (not shown) can be run along the track R.

A large number of pressure loss holes formed in circular holes having a diameter of 10 mm were provided. The arrangement is as shown in the figure, and the number of the tunnel buffer is set so as to gradually decrease from one end to the other end. Specifically, based on the results of the numerical analysis described above, the analysis results showed that the best results were obtained when the opening ratio near the buffer inlet was 14%, and as a comparative example, the opening ratio was 45%. A model experiment was carried out for the one with the aperture ratio of zero (fully closed). In addition, in this model experiment, as shown in Fig. 6, a tunnel buffer with a pair of triangular walls S (enclosure wall) connected to one end of a cover M1 having an aperture ratio of 14% was also tested. Go. The triangular wall S is formed by processing a steel plate into a right-angled triangle having an elevation angle of 0 (15 degrees in the present embodiment), and is formed so that its height matches the height H of the cover Ml. . That is, the triangular wall S is formed so as to gradually increase from the roadbed surface toward one end of the cover M1.

In this model experiment, a high-speed railway model was run at about 500 km / h along the track R, and passed through the model M and the tunnel model t. The pressure measurement point (evaluation point) was located at a distance of 5.0 D (D: diameter of tunnel t) from the center of track R at the entrance of the buffer. The results are shown in FIGS. 7A to 7D. Figure 7A shows the experimental results for a fully closed (zero aperture ratio), and Figure 7B shows the experimental results for an aperture ratio of 45% near the buffer inlet. Fig. 7C shows the experimental results with an aperture ratio of 14%, and Fig. 7D shows the experimental results with an aperture ratio of 14% when the above-mentioned triangular wall S was further installed. I have. The horizontal axis in each figure represents the measurement time (s), and the vertical axis represents the pressure fluctuation at the measurement time.

As can be seen from FIGS. 7A to 7D, the pressure peak value (edge portion) greatly appears around time 0.42 (s) and around time 0.43 (s) for the fully closed type. I have. On the other hand, for those with an aperture ratio of 45%, the amplitude of the corresponding peak value is somewhat smaller. Then, when the aperture ratio becomes 14%, the amplitude of the peak value becomes smaller, and it can be seen that the amplitude of the peak value almost disappears in the case where the triangular wall S is provided. Note that these graphs are the results obtained by measuring the pressure energy (pressure field) generated near the vehicle due to the high speed of the vehicle and the air vibration generated from the shock absorber. Pressure energy (pressure field) is the traveling speed and vehicle This phenomenon occurs due to factors such as the cross-sectional area and cannot be completely suppressed by the tunnel buffer. In Fig. 7D, the air vibration is greatly reduced, and the waveform is similar to the pressure change due to the pressure energy (pressure field).

That is, since the low frequency air vibration is caused by the magnitude of the peak value (that is, the size of the pressure wave), the problem of the low frequency air vibration can be solved by setting the aperture ratio to 14% and further providing the triangular wall S. It can be seen that it is greatly suppressed.

Returning to FIGS. 2A to 2C, based on the results of the numerical analysis and the model experiment described above, in the tunnel buffer 1 of the present embodiment, the aperture ratio at the outermost end near one end of the cover 10 is shown. The steel plate 21 (claw pressure loss hole 30) is arranged so as to be 10 to 20%, and is configured to gradually decrease toward the other end.

As described above, according to the tunnel buffer 1 of the present embodiment, the pressure of the pressure wave generated between the high-speed railway vehicle entering the tunnel T or exiting from the tunnel T and the cover 10. A plurality of pressure loss holes 30 for adjusting the loss are provided, and the pressure loss holes 30 are disposed so as to gradually decrease from one end of the cover 10 to the other end thereof.

Therefore, it is possible to form an intermediate state in which an appropriate pressure loss is applied between the light section and the tunnel section, creating an effect as if a high-speed railway vehicle gradually enters the tunnel T. can do. In other words, the steep rise of the pressure gradient of the pressure wave (rush wave) suppresses the rise, and the change of the pressure gradient can be made smooth. As a result, it is possible to eliminate or suppress the occurrence of low-frequency air vibration due to the rush wave of the high-speed railway vehicle, and it is possible to solve the rattling problem of the fittings of the private house around the tunnel.

In the above embodiment, the case where the high-speed railway vehicle enters the tunnel T has been described as an example. However, the same effect can be obtained when the vehicle exits the tunnel T. Obtainable. That is, according to the configuration of the above embodiment, the pressure loss hole 30 gradually increases from the tunnel entrance to the opening 10a of the tunnel buffering hole. The pressure loss of the pressure wave generated between the high-speed rail car and the cover 10 gradually decreases, but the same is true in that the change in the pressure gradient is smoothed.

Therefore, even when a high-speed railway vehicle exits the tunnel T, the occurrence of low-frequency air vibration due to the exit wave can be eliminated or suppressed, and as a result, the problem of rattling of the fittings of the private house around the tunnel can be solved. be able to.

As described above, the embodiments of the present invention have been described. However, the embodiments of the present invention are not limited to the above-described embodiments, and may take various forms within the technical scope of the present invention. Needless to say.

For example, in the above-described embodiment, the cover 10 of the tunnel buffer 1 has a rectangular cross section formed by using a large number of rectangular steel plates 21 and PC plates 20. Is not limited to such a shape, and for example, may be formed in a semicircular cross section. Instead of using a large number of steel plates or PC plates, it is also possible to construct a cover using, for example, a reinforced concrete, and then form a pressure loss hole at a predetermined location. Furthermore, although an example in which a plurality of circular pressure loss holes 30 are formed in the steel plate 21 has been described, the pressure loss holes may be formed in other shapes such as a square hole.

In the above embodiment shown in FIGS. 2A to 2C, the enclosure wall (corresponding to the triangular wall S) was not mentioned, but as can be seen from the model experiment, the effect of reducing the pressure wave is good. Therefore, it is preferable that a similar triangular wall is provided. Also, in the above model experiment, a configuration was shown in which a triangular wall S with an elevation angle of 15 degrees was provided as a surrounding wall, but if the elevation angle is 0 degrees or less (preferably 15 degrees or less), Good effect can be obtained I know from another experiment.

Furthermore, in the above-described embodiment, the description has been given of the tunnel buffer for a high-speed railway. In addition, as a measure against noise in densely populated houses and as a measure against snow in heavy snowfall areas, the installation of a tunnel-like structure (hood) in the lighting structure (viaduct, etc.) can be assumed. In this case, there is no actual tunnel, but the situation is similar to the existence of a tunnel entrance. Naturally, in this case, it is also possible to apply a buffer using a perforated plate (that is, a buffer using a perforated plate (steel plate 21 in the above embodiment) is not applicable only to the tunnel. However, the same performance as that of the present invention can be obtained by installing the device in a location exhibiting a similar appearance.) Industrial applicability

As described above in detail, according to the present invention, low-frequency air vibration generated when a high-speed vehicle enters and exits a tunnel can be eliminated or suppressed.

Claims

The scope of the claims

1. a long cover having an open portion at one end and the other end connected to the entrance of the tunnel structure;

A plurality of pressure drops provided on the wall surface of the cover to adjust pressure loss of a pressure wave generated between the high-speed vehicle entering the tunnel structure or exiting the tunnel structure and the cover. Holes and

A buffer with

A plurality of the pressure loss holes are provided in the circumferential direction near one end of the cover, and are arranged so as to gradually decrease from one end to the other end of the cover. .

2. The buffer according to claim 1, wherein the buffer is configured as a tunnel buffer for a high-speed railway.

3. The method according to claim 1, wherein an opening ratio of a wall surface of the cover by the pressure loss hole is 10% to 20% at an outermost portion near the one end. Buffer as described.

4. The buffer according to any one of claims 1 to 3, wherein the pressure loss hole is formed from near one end to near the other end of the cover.

5. The pressure loss hole is formed such that its hole diameter or hole width is such that the individual pressure loss coefficient in the pressure loss hole when the high-speed vehicle passes through the cover is substantially constant. The buffer according to any one of claims 1 to 4, characterized in that:

6. The shock absorber according to any one of claims 1 to 5, wherein the peripheral edge of the pressure loss hole is chamfered.

7. The buffer according to any one of claims 1 to 6, further comprising:

An enclosure wall connected to one end of the cover,

The enclosing wall has a side wall that gradually increases from a track surface toward one end of the cover. A buffer which is formed as described above.

8. The buffer according to any one of claims 1 to 7, wherein the pressure loss hole is provided in an upper wall of the cover.