JP3739642B2 - Model experiment method of tunnel pressure wave - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tunnel pressure wave model test method in a high-speed railway.
[0002]
[Prior art]
When the train enters the tunnel entrance, a pressure wave is formed in the tunnel, and this pressure wave propagates through the tunnel at almost the speed of sound. When this pressure wave reaches the outlet, a pulsed pressure wave is emitted to the outside and is observed as low-frequency air vibration. This pulsed pressure wave is called a “tunnel micro-pressure wave” and is known to be approximately proportional to the pressure gradient in front of the pressure wave inside the tunnel.
[0003]
This tunnel micro-pressure wave increases in proportion to the third power of the train speed, which may cause environmental problems peculiar to high-speed railways such as blasting sounds around the wellhead and rattling of house fittings. Such a problem has occurred since the opening of the Sanyo Shinkansen between Okayama and Hakata in 1975. In particular, the compression wave formed when the train head enters the tunnel generates a large tunnel micro-pressure wave at the tunnel exit with a long slab track. I found that it was generated. Many studies have been conducted so far to elucidate this phenomenon and develop countermeasures for reducing the phenomenon.
[0004]
FIG. 8 is an explanatory diagram of the phenomenon of generation of such tunnel micro-pressure waves.
[0005]
As shown in this figure, when the train 101 enters the tunnel entrance 103, a compression wave is formed. The compression wave propagates through the tunnel 102 at almost the speed of sound. When the compression wave reaches the tunnel exit 104, a pulse shape is formed. Of pressure waves. This pulsed pressure wave is called a tunnel micro-pressure wave. Reference numeral 105 denotes the radiation state of the tunnel micro-pressure wave.
[0006]
As one of the means of this research and development, model experiments using model trains and model tunnels to simulate the phenomenon when trains enter the tunnel are effective and are currently being carried out. In the model experiment, if you try to capture the moment of entry to the tunnel entrance at the top of the train, which is most important in the phenomenon of tunnel micro-pressure waves, the model tunnel required for this need not be so long, for example 60 minutes When simulating a train running at a speed of about 200 to 300 km / h with a scale model of about 1, it is sufficient that the total length of the model train is about 1 m and the total length of the model tunnel is about 10 m.
[0007]
By the way, as aerodynamic phenomena related to trains and tunnels, in addition to this tunnel micro-pressure wave, “tunnel entry wave” in which a pulsed pressure wave is released directly from the entrance to the outside when entering the tunnel, "Tunnel exit wave" in which a pulsed pressure wave is radiated directly from the exit, and a phenomenon in which a pressure wave is generated when a train passes through a cross-section change section inside a tunnel, such as an equipment mine, an inclined shaft, or a tunnel intermediate station There are many phenomena. These are generally smaller than the tunnel micro-pressure wave, and have not been a problem so far. However, there is a possibility that low-frequency air vibration problems similar to those of tunnel micro-pressure waves may occur due to future train speed increases and future floating railways in practical use. There is.
[0008]
For the research and development of these pressure wave phenomena, the model experiment using the above-mentioned experimental device is considered to be one of the effective means like the tunnel micro pressure wave.
[0009]
FIG. 9 is a block diagram of an example of such a conventional model experiment apparatus.
[0010]
In this figure, 201 is a model train, 202 is a piano wire for guiding the model train, 203 is a launching device, 204 is a speed sensor, 205 is a model tunnel, 206 is a pressure gauge provided in the model tunnel 205, 207 is It is a braking device.
[0011]
FIG. 10 is an explanatory diagram of a tunnel entry / exit wave.
[0012]
As shown in this figure, when a train 301 enters and exits a tunnel 302, a pressure wave is formed not only inside the tunnel 302 but also outside the tunnel 302 and propagates to the surroundings. Reference numeral 303 denotes a tunnel entrance, 304 denotes a tunnel exit, 305 denotes the tunnel entry wave, and 306 denotes the tunnel exit wave.
[0013]
As described above, tunnel entry / exit waves are generally smaller than tunnel micro-pressure waves and have not been a problem so far. However, there is a possibility that it may become a problem in the future speeding up of trains and the practical application of future floating railways, and it is necessary to clarify the phenomenon and develop a countermeasure for reducing it. As one of the tools for that purpose, a model experiment that has been conducted for tunnel micro-pressure waves can be considered.
[0014]
[Problems to be solved by the invention]
The research on tunnel micro-pressure waves so far has mainly focused on the compression wave formed when the train head enters the tunnel , as described above. Therefore, it was sufficient for the conventional model experiment to capture only the moment when the top of the model train entered. However, as for other pressure wave phenomena to be studied in the future, the phenomenon over the entire length of the train from the head to the tail is important, and it is necessary to take a longer time to measure the model experiment than that for the conventional tunnel micro-pressure wave. is there. However, the devices that have been used in the research of conventional tunnel micro-pressure waves have the following problems.
[0015]
As shown in FIG. 8, the pressure wave formed in the model tunnel at the time of entry of the model train propagates at almost the speed of sound, and radiates the tunnel micro-pressure wave at the exit of the model tunnel. At this time, the pressure wave in the tunnel is reflected at the exit (open end reflection) and returns to the entrance side through the tunnel. That is, the pressure wave in the tunnel is repeatedly reflected at the entrance and exit many times, and reciprocates between them at almost the speed of sound, and radiates a tunnel micro-pressure wave every time it is reflected.
[0016]
Due to this property, for example, the following occurs during model experiments.
[0017]
(1) At the exit, when trying to measure the tunnel exit wave when the train exits the tunnel, the tunnel micro-pressure wave due to reflection is radiated many times in a short time at the exit, so the exact exit wave of the tunnel There are restrictions on measurement.
[0018]
(2) At the entrance, when trying to measure the tunnel entry wave when the train enters the tunnel, the pressure wave at the beginning of the train is reflected at the exit, and the tunnel micro-pressure wave is emitted at the entrance. In an experiment using a long model train, a tunnel micro-pressure wave is radiated from the entrance before the entire length of the train has entered the entrance, and there are restrictions on accurate measurement of the tunnel entry.
[0019]
(3) At the middle part of the tunnel, when trying to measure the pressure wave generated when the train passes through the cross-section change part in the tunnel, the pressure wave at the time of entry remains in the tunnel while reciprocating. In this case, there are restrictions on the accurate measurement of the pressure wave generated.
[0020]
In order to clear the problems (1) to (3), it is desirable to make the length of the model tunnel as long as possible. In other words, if the distance between the tunnel entrance and the exit is increased, it takes time for the pressure wave in the tunnel to reciprocate between them, so a time margin that is not affected by this pressure wave is created, and the target phenomenon is accurately detected. It becomes easy to measure. However, due to cost and space constraints, it is not easy to manufacture an experimental apparatus having a length necessary to sufficiently clear the problems (1) to (3).
[0021]
Therefore, the present invention provides a semi-infinite or infinite length tunnel with no entrance or exit when conducting an experiment using a model tunnel having a relatively short overall length, which has been used in conventional tunnel micro-pressure wave research. It is intended to provide a model experiment method for tunnel pressure wave that can be simulated at low cost and accurately and under ideal conditions according to the purpose of the experiment.
[0022]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides
[1] In the model experiment method for pressure waves inside and outside the tunnel, when the experiment is conducted using a model tunnel with a short overall length, the pressure wave formed at the tunnel entrance when the model train enters, and the pressure wave By reducing the influence of reflection at the tunnel exit, an infinite or semi-infinite tunnel can be easily simulated.
[0023]
[2] In [1] above model the experimental procedure tunnel pressure wave described, together with placing the slit at the inlet side of the model tunnel, a microphone arranged near the pressure gauge and or tunnel outlet in said model tunnel, the tunnel It is characterized by measuring the pressure wave inside and outside the tunnel when the model train exits the tunnel on the exit side.
[0024]
[3] In [1] above model the experimental procedure tunnel pressure wave described, with placing orifice to the model tunnel exit, a microphone placed in a pressure gauge and or tunnel entrance near the said model tunnel, the tunnel The pressure wave inside and outside the tunnel is measured when the model train enters the tunnel at the entrance side of the tunnel.
[0025]
[4] In [1] above model the experimental procedure tunnel pressure wave described, the side slits on the model tunnel entrance mouth, the place orifice model tunnel exit, a further pressure gauge within said model tunnel It is arranged to measure the pressure wave when the model train passes through the cross-section changing part in the tunnel at the middle part of the tunnel.
[0026]
In the present invention, the orifice means not only a circulation port having a single hole, but also a reflected wave reduction effect using a perforated plate having an opening ratio (ratio of opening area to tunnel cross-sectional area) of the same degree as that. It has a broad meaning including those that play.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0028]
FIG. 1 is a diagram showing a tunnel pressure wave model test method according to the first embodiment of the present invention. In this embodiment, a slit is provided at the entrance of the tunnel, and a tunnel exit wave near the tunnel exit is measured. Fig. 1 (a) shows an example of the measurement of pressure waves radiated from the tunnel entrance without conventional slits (without countermeasures), and Fig. 1 (b) shows the case where a slit is installed at the entrance of the tunnel to the outside. Measurement examples of the radiated pressure wave are shown.
[0029]
In these drawings, 1 is a model train, 2 is a launching device, 3 is a conventional model tunnel, 4 is a pressure gauge provided in the model tunnel 3, 5 is a microphone, 11 is a model tunnel (with a slit on the entrance side), 12 is It is a tunnel entrance side slit.
[0030]
As shown in FIG. 1B, by installing a slit 12 that is sufficiently longer than the train on the side of the tunnel entrance, as shown in FIGS. 2 and 3, the pressure wave front formed in the model tunnel 11 when the train enters. It is possible to greatly relax the pressure gradient and reduce the tunnel micro-pressure wave radiated at the exit. This can simulate the conditions of a train traveling in a semi-infinite tunnel without an entrance, and is suitable for conducting an experiment for measuring the exit wave of a tunnel when the train exits the tunnel, for example, on the exit side.
[0031]
FIG. 2 shows the pressure waveform in the tunnel before and after installation of the inlet slit 12 measured by the pressure gauge 4 in the tunnel in FIG. Compared with the vicinity of 53 ms), the gradient of the pressure wave front surface when the slit 12 is present (around 30 to 50 ms) is greatly relaxed.
[0032]
FIG. 3 is a radiation pressure waveform measured before and after installation of the entrance slit 12 measured by the microphone 5 in the vicinity of the tunnel exit in FIG. The model train 1 has exited around 120 to 135 ms at the exit, but before installation of the slit 12, the tunnel micro-pressure wave due to the pressure wave formed when entering the entrance was observed several times before exiting the exit. Yes. However, it can be seen that the installation of the slit 12 significantly reduces these tunnel micro-pressure waves, and the tunnel exit wave upon exit exit is accurately measured.
[0033]
FIG. 4 is a diagram showing a tunnel pressure wave model test method according to the second embodiment of the present invention. In this embodiment, an exit orifice is installed, and a tunnel rush wave near the tunnel entrance is measured. Fig. 4 (a) shows an example of the measurement of pressure waves radiated from the tunnel entrance without conventional orifices (without countermeasures), and Fig. 4 (b) shows that the orifice is installed at the exit of the tunnel. Measurement examples of the radiated pressure wave are shown.
[0034]
As shown in FIG. 4 (b), if the orifice 22 is installed at the exit of the model tunnel 21, the pressure wave formed in the model tunnel 21 at the time of entry of the model train 1 reaches the exit as shown in FIG. The reflection at the opening end can be greatly reduced. This can simulate the conditions of a train traveling in a semi-infinite tunnel without an exit, and is suitable for conducting an experiment for measuring a tunnel entry wave when a train enters a tunnel, for example, on the tunnel entrance side.
[0035]
FIG. 5 shows the pressure waveform in the tunnel before and after installation of the outlet orifice 22 measured by the pressure gauge 4 in the model tunnel 21 in FIG. The pressure wave in the vicinity of 30 to 38 ms is formed at the entrance of the inlet, and the reflected wave (48 to 56 ms) is greatly reduced by the installation of the outlet orifice 22. Thereby, the tunnel micro-pressure wave radiated when the reflected wave reaches the entrance can be greatly reduced.
[0036]
FIG. 6 is a diagram showing a tunnel pressure wave model experiment method according to the third embodiment of the present invention, in which both the entrance slit and the exit orifice are installed, and the train has a cross section change portion in the tunnel in the middle of the tunnel. Suitable for measuring pressure waves as they pass. In this embodiment, FIG. 6 (a) shows the pressure wave measurement of a conventional tunnel without a slit / orifice (without countermeasures), and FIG. 6 (b) shows the pressure wave when an inlet side slit and an outlet orifice are installed in a model tunnel. Each example of measurement is shown.
[0037]
If both the entrance side slit 12 and the exit orifice 22 are installed in the model tunnel 31 as shown in FIG. 6B, as shown in FIG. 7, the train traveling in an infinite length tunnel without entrance and exit is shown. This makes it possible to simulate conditions, and is suitable, for example, for an experiment in which a pressure wave is measured when a train passes through a cross-section changing portion in a tunnel at an intermediate portion of the tunnel. Reference numeral 32 denotes a pressure gauge provided in the tunnel 31.
[0038]
FIG. 7 shows the pressure waveform in the tunnel before and after installation of the inlet slit 12 and the outlet orifice 22 measured by the pressure gauge 32 in the tunnel 31 in FIG. However, in order to clarify the effect of the entrance slit and the exit orifice, this waveform was measured in a model tunnel having no cross-sectional change part such as a branch pit. By installing the inlet slit 12, the slope of the pressure wave front at the time of entry (around 22-25ms) is remarkably relaxed, and by installing the outlet orifice 22, the reflection at the open end of the pressure wave at the time of entry (around 52-58ms) is also greatly improved. It has been eased. The pressure wave in the vicinity of 58 to 64 ms before the slit / orifice is installed is a pressure wave in the vicinity of 52 to 58 ms further reflected at the opening end at the inlet, but this is naturally reduced. The pressure drop in the vicinity of 28 to 35 ms is obtained by capturing the negative pressure around the train when the model train 1 passes just beside the pressure gauge 32. This is one of the basic phenomena observed even in the middle part of the infinite length tunnel, and should not be the object of relaxation or reduction in the present invention.
[0039]
In addition, the effect that an exit orifice reduces the opening end reflection of a pressure wave is decided by the opening ratio, and may become smaller than the cross-sectional area of a model train depending on the case. In this case, the model train will collide with the orifice at the exit.For example, if the target phenomenon is measured before this collision, such as the measurement of the tunnel rush wave at the entrance side, There is no problem. However, the material of the orifice may be appropriately selected so that the model train is not destroyed at the time of collision, or if possible, the orifice may be opened and closed so that the route is opened only when the model train passes the exit.
[0040]
In addition, this invention is not limited to the said Example, A various deformation | transformation is possible based on the meaning of this invention, and they are not excluded from the scope of the present invention.
[0041]
【The invention's effect】
As described above in detail, according to the present invention, pressure waves inside and outside a tunnel in a high-speed railway can be accurately measured at a low cost with a model tunnel having a short overall length.
[Brief description of the drawings]
FIG. 1 is a diagram showing a tunnel pressure wave model test method according to a first embodiment of the present invention.
FIG. 2 is a diagram showing measurement results (No. 1) by a tunnel pressure wave model test method according to the first embodiment of the present invention.
FIG. 3 is a diagram showing measurement results (No. 2) by a tunnel pressure wave model test method according to the first embodiment of the present invention.
FIG. 4 is a diagram showing a tunnel pressure wave model test method according to a second embodiment of the present invention.
FIG. 5 is a diagram showing a measurement result of a tunnel pressure wave model test method according to a second embodiment of the present invention.
FIG. 6 is a diagram showing a tunnel pressure wave model test method according to a third embodiment of the present invention.
FIG. 7 is a diagram showing a measurement result of a tunnel pressure wave model test method according to a third embodiment of the present invention.
FIG. 8 is an explanatory diagram of a phenomenon of generation of tunnel micro-pressure waves.
FIG. 9 is a configuration diagram of an example of a conventional model experiment apparatus.
FIG. 10 is an explanatory diagram of tunnel entry / exit waves.
[Explanation of symbols]
1 Model train 2 Launcher 3 Conventional model tunnel (no countermeasures)
4,32 Pressure gauge 5 Microphone 11 Model tunnel (with entrance side slit)
12 Slit 21 Model tunnel (with exit orifice)
22 Orifice 31 Model tunnel (with entrance side slit and exit orifice)

Claims (4)

In the model experiment method for pressure waves inside and outside the tunnel,
When conducting experiments using a model tunnel with a short overall length, by reducing the influence of pressure waves formed at the tunnel entrance when the model train enters and the reflection of the pressure waves at the tunnel exit, A model test method for tunnel pressure waves, which is a model that simulates a semi-infinite tunnel easily. In model experiments method tunnel pressure wave according to claim 1, together with placing the slit at the inlet side of the model tunnel, a microphone arranged near the pressure gauge and or tunnel outlet in said model tunnel models at the tunnel outlet A model test method for tunnel pressure waves, characterized by measuring pressure waves inside and outside the tunnel as the train exits the tunnel. In model experiments method tunnel pressure wave according to claim 1, together with placing the orifice in said model tunnel exit, the microphone was placed in a pressure gauge and or tunnel entrance near in the model tunnel, at the inlet side of the tunnel A model test method for tunnel pressure waves, characterized by measuring the pressure waves inside and outside the tunnel when the model train enters the tunnel. In model experiments method according to claim 1, wherein the tunnel pressure wave, a side slit in the model tunnel entrance mouth, the place orifice model tunnel exit, further arranged a pressure gauge within said model tunnel, the tunnel A tunnel pressure wave model experiment method characterized by measuring a pressure wave when a model train passes through a cross-section change section in a tunnel at an intermediate portion.

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