JP6561018B2 - Tunnel blast noise reduction device - Google Patents

Description

  The present invention can be installed in a short period of time without using large heavy machinery, can be easily removed after installation, and the excavation work can be resumed promptly, and the leakage and diffusion of back gas and dust to the wellhead side are prevented, In addition, the present invention relates to a blasting sound reduction device for a tunnel that can reduce the blasting sound compared to the conventional method and reduce the influence of the blasting sound on the surrounding environment.

  For example, blasting is used for excavation of a mountain tunnel, but the blasting sound generated on the face at the time of blasting includes an extremely low frequency region to a high frequency region, and very large energy is instantaneously generated. In particular, low-frequency sound and blast pressure are hardly attenuated in the mine, so even if the excavation progresses and the propagation distance from the face to the wellhead becomes long, the influence on the surrounding environment is large, and improvement has been desired in advance. .

Various proposals have been made to meet such demands.
For example, a sound insulation wall and a sound insulation door are provided facing the wellhead, and the sound insulation wall is constructed by installing a plurality of support columns, and a concrete or iron sound insulation panel is inserted into this support column. There is a sound-insulating wall structure that is configured to have a strength that can withstand the blast at the time of blasting, eliminates the need for welding and spraying of concrete during installation, and reduces labor during dismantling (see, for example, Patent Document 1).

  However, with such a sound insulation wall structure, it is necessary to place foundation concrete and struts, and to insert a sound insulation panel, which takes time for construction and requires the use of heavy machinery. In the structure closed by the sound insulation panel and the sound insulation door, there is a limit to the reduction of the blasting sound, and the reduction of the low frequency sound could not be expected.

  As another method, a tunnel low-frequency sound reduction device is provided between the face of the tunnel and the wellhead, and the reduction device is erected so that the panel rows having a U-shaped cross section are spaced apart from each other in the axial direction of the tunnel. In addition to partitioning both sides with partition walls, the spaced portions of the opposing panel rows are arranged in communication with each other, and the low frequency sound propagating between the panel rows is absorbed by the separated portions, and the absorbed low frequency sound is There is a tunnel low-frequency sound reduction device that absorbs resonance in a space between a panel row and a side wall portion of lining concrete (see, for example, Patent Document 2).

  However, this reduction device requires the construction of a large low-frequency sound reduction device in the tunnel pit, which increases the labor and cost of the large-scale construction, and also changes the resonance frequency of the panel row to change the resonance frequency. Since the frequency of the target sound to be reduced is adjusted, it is not possible to easily deal with various frequency reductions. Actually, it is limited to a limited frequency reduction, and the spacing between each panel row is made constant. It is difficult to reduce the frequency, and it is difficult to reduce the specific frequency. Moreover, when changing the resonance frequency, it is troublesome to adjust the separation dimension of each panel unit. was there.

  Furthermore, as another method, a tunnel silencer is provided between the tunnel face and the wellhead to mute the noise generated on the face side, and the silencer includes a metal plate duct arranged parallel to the axial direction of the tunnel. In addition to forming a large number of through holes on the circumferential surface of the duct, both ends of the duct are closed with bulkheads, and the through holes, their pitches, the length and volume of the duct are arbitrarily selected according to the conditions of the tunnel excavation site There is a tunnel silencer that is set to mute the noise generated on the face side due to the cross-sectional change in the pit by the duct and each partition wall (see, for example, Patent Document 3).

  However, this tunnel silencer requires the construction of a large duct in the tunnel pit, which increases the labor and cost of the construction, and the length of the through hole, its pitch, and duct according to the conditions of the tunnel excavation site. Therefore, the setting work is complicated, and the same conditions for the tunnel excavation site are adopted to simplify the work. However, it is difficult and arbitrary to judge the same condition of the excavation site. As a result, it was impossible to obtain a stable noise-reducing effect, and it was necessary to move the duct along with the progress of tunnel excavation, which caused the movement of the duct to become complicated, and the construction period was prolonged and the construction cost increased. .

  Furthermore, as another method, the tunnel well or the inside of the tunnel is closed with a predetermined partition, one end is opened in the tunnel well, the other end is closed, and a plurality of pipes having different path lengths are connected to the predetermined partition. Installed on the face side, the sound wave that entered the tube with a predetermined wavelength phase delayed by the reciprocation of the path length is formed in the opposite phase to the sound wave from the blasting sound source in the tunnel tunnel, and these are generated from the blasting sound source in the tube. There is a blasting sound muffling method for a tunnel that cancels the sound wave and mute (see, for example, Patent Document 4).

  However, in order to obtain a reliable and precise silencing effect, this tunnel blasting sound silencing method provides multiple pipes with different path lengths all over the ceiling surface toward the tunnel entrance. The arrangement becomes complicated and complicated, and the installation of the pipe is heavy using heavy machinery, and it takes a lot of time and labor to remove the pipe at the end of excavation, which increases the construction period and costs. There were problems such as encouraging soaring prices.

  Furthermore, as another method for reducing the blasting sound of a tunnel, a soundproof wall is provided on the tunnel entrance side and the inner side of the tunnel, and a box-shaped Helmholtz resonator assembly is disposed between the soundproof walls, and the blasting sound is transmitted to the assembly. Some are reduced by introducing them into the end openings (see, for example, Patent Document 5).

  However, this method of reducing blasting sound requires the production of a large number of Helmholtz resonator assemblies and placement between the soundproof walls, and the construction of a new soundproof wall and a large number of Helmholtz resonator assemblies as excavation progresses. There was a problem that the arrangement was required and the construction period was prolonged and the construction cost increased.

In this way, the method using absorption and resonance of the blasting sound has problems that the production of components is generally complicated and installation work is large, and the construction period is prolonged and the construction cost is increased. There is a problem that the desired and stable effect cannot be obtained for the silencing effect.
Accordingly, various methods using bag bodies filled with air have been proposed as other tunnel blasting sound reduction methods for solving such problems.

For example, air is filled into a strong, flexible and lightweight fiber bag-like protective device, and this is installed in a screen in a pit separated from the face and closed, and the outer surface of the protective device such as a string or bar There is a protection device such as blasting provided with a posture adjusting means (for example, see Patent Document 6).
This protective device is easy to manufacture and can be used easily, and it has the advantage that the posture of the protective device can be easily adjusted by the posture adjusting means, and the protective device can be easily installed and removed. There was a problem that it was difficult to form a self-supporting posture at the time, and there was a limit to installation in a large-area mine.

  In order to solve this problem, a protective bag body filled with air is attached to a mounting frame, and the frame is constructed by separating the face side gate-type frame and the well-portion side gate-type frame in the front-rear direction. The protective bag body of each section divided into a plurality of sections in the mine is held, the bag body is formed by dividing the section in the mine into a plurality of sections, and the outer peripheral edge of each bag body is formed on the bottom surface or inner periphery of the tunnel. The mounting base is movably installed on the bottom of the tunnel, and after blasting, the protective bag is shrunk and the inside of the mine is maintained, and the mounting base is pulled to the face side. There is a protection device for tunnel blasting that efficiently performs excavation work of a tunnel having a cross section (see, for example, Patent Document 7).

  However, since this protective device for blasting holds each layer of protective bag body between the face side gate type frame and the pit side gate type frame, the impact of the protective bag body due to stepping stones and blasts is large, There was a risk of damage and breakage, and there was concern that the gas and dust would leak and diffuse to the wellhead side.

  For this reason, an air-absorbing bag body and an air-tight bag body, which are filled with air, are installed back to back in the tunnel tunnel, and the surface of the shock-absorbing bag body faces the face and the air-tight bag body The surface of the air bag is arranged toward the wellhead side, a plurality of exhaust ports are formed on the other side of the shock absorbing bag body, an air exhaust opening is provided in the airtight bag body corresponding to the exhaust port, and blasting is performed. The air from the shock absorbing bag is exhausted from the exhaust port by the blast and flying stones at the time, and this is exhausted from the opening to the inside of the pit to contract the shock absorbing bag to absorb the impact of flying stones and blasts. On the other hand, there is a protective device for tunnel blasting in which the shock absorbing bag body and the airtight bag body are superposed and set up and held between a pair of mounts installed in the mine (for example, (See Patent Document 8).

  However, this protective device for tunnel blasting requires a bag body that exclusively absorbs the shock and a bag body that prevents the leakage of the subsequent gas, and forms a plurality of openings in them, making the structure complicated and difficult to manufacture. In addition, the two-layer structure of the shock absorbing bag body and the airtight bag body held between the mounts does not provide sufficient shock absorbing effect and prevention of leakage of the back gas and dust. There was anxiety that it leaked and spread.

Japanese Patent Laid-Open No. 2007-27785 Japanese Patent Laying-Open No. 2015-83756 Japanese Patent No. 5788888 Japanese Patent No. 5454369 JP 2014-74328 A Japanese Patent No. 3818985 JP 2014-227786 A JP 2014-227787 A

  The present invention solves such problems, can be installed in a short period of time without using large heavy machinery, can be easily removed after installation, and the excavation work can be resumed promptly, and the rear gas and dust to the wellhead side An object of the present invention is to provide a blasting sound reduction device for a tunnel that can prevent leakage and diffusion, reduce the blasting sound compared to the conventional method, and reduce the influence of the blasting sound on the surrounding environment. .

According to the first aspect of the present invention, a bag body infused with air is installed in a well separated from the face of the tunnel, and the side peripheral surfaces of the bag body are installed on the inner surface and the bottom surface of the well so that the inside of the well can be closed. In the blasting sound reduction device for a tunnel having a device, the bag body is installed in three layers, and the air pressure of the bag body arranged on the face side and the bag body arranged on the most well side opposite to the face side is set. Set to approximately the same pressure, and set the air pressure of the intermediate bag body to a lower pressure than the air pressure of the bag body located closest to the face side or the face side opposite the face side, and compress the face side bag body The displacement is absorbed by the intermediate bag, and the blast sound, blast and shock are buffered, and the displacement of the intermediate bag is held by the last bag, making the three-layer bag safe and stable. I try to install it.

The invention of claim 2 divides the cross section in the tunnel mine into a plurality of sections, superimposes and installs three layers of bags in each section, and places the air pressure of the intermediate bag on the face side. Set the air pressure of the bag body located on the farthest side opposite to the face side to a higher pressure than the air pressure of the intermediate bag body, and smooth the compression displacement of the face side bag body. Absorbs and cushions, and the tension displacement acts on the bag body arranged on the most wellhead side opposite to the adjacent face side, and the air pressure of the bag body arranged on the most wellhead side opposite to the face side is intermediate. The air pressure of the bag body is set to be higher than the air pressure of the bag body, so that the tension or compression displacement of the intermediate bag body is strongly received, and applied to excavation of a tunnel with a large cross section. Absorbed by the intermediate bag, it dampens blasting sound, blast and impact .

The invention of claim 1 sets the bag body in three layers, and sets the air pressure of the bag body arranged on the face side and the bag body arranged on the most well side opposite to the face side to substantially the same pressure. Since the air pressure of the intermediate bag body is set to be lower than the air pressure of the bag body arranged on the face side or the face side opposite to the face side, the compression displacement of the face side bag body is set to the intermediate part. It absorbs by the bag body, cushions blasting sound, blast and shock, and holds the displacement of the middle bag body by the last bag body, so that the three-layer bag body can be installed safely and stably it can.

The invention of claim 2 divides the cross section in the tunnel mine into a plurality of sections, superimposes and installs three layers of bags in each section, and places the air pressure of the intermediate bag on the face side. Since the air pressure of the bag body arranged on the most well side opposite to the face side is set to be higher than the air pressure of the intermediate bag body, the compression displacement of the face side bag body is smooth. It absorbs and cushions, and the tension displacement acts on the bag body arranged on the most wellhead side opposite to the adjacent face side, and the air pressure of the bag body arranged on the most wellhead side opposite to the face side is intermediate. It can be set to a pressure higher than the air pressure of the bag body of the section, and can strongly accept the tension or compression displacement of the bag body of the middle section, and can be applied to excavation of a tunnel with a large section, and the bag body on the face side can be compressed displacement is absorbed by the bag body of the middle part, it is buffered blasting sound and blast and shock That.

It is sectional drawing which shows typically the condition which installed the protective device of the basic composition applied to this invention in the tunnel of a tunnel. It is sectional drawing which expands and shows the protection apparatus of the basic composition applied to this invention. It is sectional drawing which expands and shows the principal part of FIG. It is sectional drawing which shows typically the condition at the time of the blast of the protection apparatus of the basic composition applied to this invention.

It is the front view which looked at the protective device which applied this invention to excavation of a large section tunnel from the wellhead side. It is a side view which expands and shows the protection-device mounting stand used for construction of the protection device which applied this invention to excavation of a large section tunnel. It is the front view which looked at the situation after construction of the protection device which applied the present invention to excavation of a large section tunnel from the face side, and is expanding and blocking up to each section in a mine.

  Hereinafter, the present invention will be described with reference to the illustrated embodiment. In FIGS. 1 to 4, reference numeral 1 denotes a tunnel that is being excavated. The protective device 4 is installed adjacently. In the figure, 2 a is the ceiling surface or inner peripheral surface of the mine 2, and 5 is the mouth side of the mine 2.

  The protective device 4 according to the embodiment is composed of a plurality of bag bodies 4a to 4c having the same shape or different thicknesses, and these are filled with a predetermined pressure of air inside and are substantially fan-shaped or rectangular having a curved surface on the outer periphery. Or a rectangular shape, and by arranging them in a plane, they are formed into a substantially semicircular or bullet shape that is substantially the same shape as the cross section of the mine 2 or the inner peripheral surface 2a, and is substantially the same thickness after air filling. It is formed in a thick plate.

  The air pressure of each bag body 4a to 4c is about 0. 18 to 0.2 MPa of the bag body 4a arranged on the face 3 side, and the bag body 4b at the middle position is about 0% of about 80% of the bag body 4a. The rearmost bag body 4c disposed on the wellhead 5 side is set to approximately the same pressure as the bag body 4a.

These bags 4a to 4c are formed into a predetermined shape by nylon (registered trademark) which is a tough, flexible, lightweight, thin (0.31 mm) synthetic fiber, and high strength, lightweight, thin ( A protective sheet 6 made of aramid fiber (0.9 mm) is coated or sewn.
Then, a robust and thin (0.85 mm) polyester explosion-proof sheet 7 is coated or sewn on the opposite surface side of the bag body 4a disposed on the face 3 side. In the figure, reference numeral 8 denotes a plurality of pressing fastener cloths provided on the opposing surfaces of the respective bag bodies 4a to 4c so that the bag bodies 4a to 4c can be easily attached and detached.

The tunnel blast noise reduction device configured as described above requires the production and installation of a plurality of protection devices 4 applied thereto.
The protective device 4 is manufactured in a bag shape using nylon (registered trademark), and the shape and dimension thereof is a substantially semicircular or a bullet-shaped partial shape substantially the same as the cross section of the pit 2 to be excavated. For example, it is formed into a substantially fan shape, a rectangle having a curved surface on the outer periphery, or a rectangle, and a protective sheet 6 made of aramid fiber is covered or sewn on the surface of the fabric.

Among these, for the bag body 4a installed on the face 3 side, an explosion-proof sheet 7 made of polyester is coated or sewn on a substantially half circumferential surface on the protective sheet 6.
Then, the press fastener cloth 8 is sewn to the upper and lower positions of the bag body 4a opposite to the explosion-proof sheet 7 and the corresponding positions of the front and rear surfaces of the bag bodies 4b and 4c.

As described above, the bag bodies 4a to 4c have slightly different shapes depending on the attachment positions, but the bag bodies 4a to 4c at the same attachment positions are manufactured to have the same shape and dimensions.
Moreover, since the production of each bag 4a to 4c is to sew a flexible fabric, it does not require a large-scale manufacturing facility and a wide manufacturing space that make full use of steel materials and concrete materials, and a conventional blast sound reduction device. Compared to the above, it can be easily manufactured, and after manufacturing or after use, the bag bodies 4a to 4c can be made compact by, for example, folding, and can be stored compactly.

When the bag bodies 4 a to 4 c thus manufactured are used for reducing the blasting sound, the bag bodies 4 a to 4 c are installed at predetermined positions in the pit 2 separated from the face 3.
In this case, the protective device 4 is configured by selecting one or two bag bodies 4b and 4c according to the construction conditions in addition to the bag body 4a to which the explosion-proof sheet 7 is sewn.
Therefore, when three bags 4a to 4c are installed in the mine 2, the bags 4a to 4c are carried into the position of the mine 2 separated from the face 3, and air is sequentially supplied to these through a blower (not shown). Inject and adjust to a predetermined air pressure to achieve the desired shock absorption effect and self-supporting.

For example, air is first injected into the bag body 4a, adjusted to a predetermined air pressure, and then installed at a predetermined position in the mine 2 that is separated from the face 3, and the upper and lower surfaces thereof are the ceiling surface or the inner peripheral surface 2a of the mine 2 Stand in contact with the bottom.
Next, the press fastener cloth 8 at the front part of the bag body 4b is joined to the press fastener cloth 8 at the rear part of the bag body 4a, and air is injected into the bag body 4b to adjust to a predetermined air pressure. It arrange | positions adjacent to the wellhead 5 side, the upper and lower surfaces are made to stand in contact with the ceiling surface of the well 2 or the inner peripheral surface 2a, and a bottom face, and it is made to stand independently through the bag 4a.

  Thereafter, the pressing fastener cloth 8 at the front portion of the bag body 4c is joined to the pressing fastener cloth 8 at the rear portion of the bag body 4b, and air is injected into the bag body 4c to adjust to a predetermined air pressure. It arrange | positions adjacent to the wellhead 5 side, the upper and lower surfaces are made to stand in contact with the ceiling surface of the well 2 or the inner peripheral surface 2a, and a bottom face, and are made to stand independently through the bag 4b. Thus, since each bag 4a-4c is joined by the press fastener cloth 8, this construction work and the removal work after use can be performed simply.

The air pressure of each of the bag bodies 4a to 4c is such that the bag body 4a disposed on the face 3 side is set to about 0.18 to 0.2 MPa as normal, and the bag body 4b at the intermediate position is about 80% of the bag body 4a. The pressure is about 0.14 to 0.16 MPa, and the bag body 4c disposed on the wellhead 5 side is set to approximately the same pressure as the bag body 4a.
That is, when three bag bodies 4a to 4c are used, the bag bodies 4a and 4c arranged on the inner and outer sides are set to normal pressure, and the bag body 4b at the intermediate position is adjusted to a slightly lower pressure. Therefore, when two bag bodies 4a and 4b are used, the bag body 4a is adjusted to a normal pressure and the bag body 4b is adjusted to a slightly low pressure.

In this way, the bags 4a to 4c are erected by being superposed and in close contact with each other, and a partition wall by the protective device 4 is formed in the pit 2 on the face 3 side.
This situation is as shown in FIGS. 1 to 3, and the upper and lower surfaces of the bags 4a to 4c are in strong contact with the ceiling surface and bottom surface of the pit 2 over a wide area, so that the airtightness of the contact portion is maintained, and the ceiling surface The protective device 4 is firmly supported by the bottom surface and firmly supported.

When the face 3 is blown up after the protective device 4 is installed in this way, the face 3 is crushed and a large amount of shear is generated, generating explosion sound, blast, stepping stones, dust, rear gas, and the like.
The blast, dust, rear gas, etc. are blocked by the protective device 4 and are prevented from flowing out to the wellhead 5 side, and the stepping stone collides with the explosion-proof sheet 7 and falls into the well 2 on the face 3 side, from an extremely low frequency range. The blasting sound including the high frequency range passes through the protective device 4 in the order of the bags 4a to 4c and is attenuated step by step.

In this case, since the protective device 4 has the plurality of bag bodies 4a to 4c arranged in a superposed manner, the damping is increased and the damping effect is improved as compared with the case where the blasting sound is passed through the single bag body.
According to the inventor's design, 3 to 5 dB or more is expected when polymerizing two bags, and 5 to 8 dB or more is expected when polymerizing three bags.
Moreover, since the air pressures of the bag bodies to be polymerized are different from each other in the embodiment, the passage resistance of the blast sound and the blast pressure is increased as compared with the case where the air pressures of all the bag bodies 4a to 4c are the same pressure. The reduction effect of blasting sound and blast pressure increases accordingly.

On the other hand, along with the explosion of the face 3, the facing surface of the bag body 4a is pressed and compressed and deformed by receiving a blast or wind pressure, and the displacement acts on the adjacent bag body 4b.
At that time, since the air pressure of the bag body 4b is adjusted to be slightly lower than that of the bag body 4a, the compression displacement of the bag body 4a is smoothly absorbed and buffered, and the strain displacement is applied to the adjacent bag body 4c. The air pressure of the working bag body 4c is adjusted to be slightly higher than that of the bag body 4b, so that the tension or compression displacement of the bag body 4b is stably received. At that time, when the blast or wind pressure exceeds the contact surface pressure or drag of the protective device 4, the protective device 4 is slightly retracted toward the wellhead 5 side to buffer the blast or wind pressure. This situation is as shown in FIG.

  Thereafter, dust and rear gas staying between the face 3 and the protective device 4 are removed through a wind pipe (not shown), and the scattered dust is removed from the wellhead 5 after the removal. Then, after carrying out, the protective device 4 is further installed on the face 3 side and excavation of the face 3 is resumed.

5 to 7 show an application form in which the above-described embodiment is applied to excavation of the tunnel 1 having a large cross section, and the same reference numerals are used for the components corresponding to the above-described embodiment.
In this applied form, 9 is a bottom surface of the tunnel 1, and a protective device mounting base 10 is installed at a central position in the pit 2 separated from the face 3.
The gantry 10 is provided with vertical columns 11 and 12 erected apart from each other, a wide horizontal frame 13 is spanned between the upper ends thereof, and the front view from the face 3 side is formed in a substantially inverted U shape. Yes.
In the figure, reference numeral 14 denotes a telescopic jack for connecting the lower ends of the left and right vertical columns 11 and 12 facing each other.

Bag body attachment materials 15 and 16 are attached along the outer surfaces of the vertical columns 11 and 12, and one end of each side bag body 17 and 18 can be bound to the attachment materials 15 and 16 via a rubber band or the like. Yes.
Further, a hanger rail 19 is attached to the rear surface of the horizontal frame 13, and the upper end portion of the central bag 20 is suspended from the hanger rail 19 so as to be movable left and right.

The side bag bodies 17 and 18 are formed in an odd-shaped rectangle having a curved surface on the outer periphery at the time of deployment, and the central bag body 20 is formed in a rectangular shape defined by the gantry 10 at the time of deployment. Is formed in a substantially fan shape when unfolded, and the shape and dimensions thereof are formed in a substantially semicircular or bullet shape substantially the same as the cross section of the mine 2 to be excavated or the inner peripheral surface 2a.
Each of the bag bodies 17, 18, 20, 26, and 27 is formed by polymerizing two or three layers of bag bodies 4a to 4c and is in close contact with each other.

In the figure, reference numeral 21 denotes a telescopic wind pipe, which is formed with a substantially octagonal flange plate 21a at the front and rear ends thereof, and the opening on the face 3 side can be closed by a partition door 22; A wind tube receiving frame 23, which is a rectangular frame, is provided directly below.
The receiving frame 23 comes into contact with the surface of the wellhead side when the side bag body 18 is deployed, so that the protrusion of the side bag body 18 to the wellhead side at the time of blasting can be suppressed.
In the figure, 24 is a rod-shaped bag body holding material erected at the front-rear position on the telescopic wind tube 21, and 25 is a rod-shaped bag body material erected at the front-rear position on the horizontal frame 13. The face sides of 26 and 27 and the side face of the wellhead can be held.

Support members 28 and 29 are attached to the lower end portions of the pair of front and rear vertical columns 11 and 12 at the lower end portion of the protective device mounting base 10, and the shape of the support members 28 and 29 is slid. Has been made possible.
A plurality of blowers 30 are installed at the upper and lower positions of the protective device mounting base 10, and air is injected into the side bags 17, 18, the central bag 20, and the upper bags 26, 27. The air pressure is adjustable.

  Reinforcing frames 31 and 32 are obliquely installed between the support members 28 and 29 and the vertical columns 11 and 12, and a plurality of manual winches 33 are attached to the reinforcing frame 31 on the wellhead side, and ropes are attached to these drums. 34 and 35 are hung, and the other end thereof is attached to the end portions of the side bag bodies 17 and 18 and the central bag body 20 so that the bag bodies 17, 18 and 20 can be opened and closed. In the figure, reference numeral 36 denotes a plurality of loop hooks provided on the reinforcing frame 31.

  The above-described applied configuration configured as described above requires the production of the protective device mounting base 10, and the base 10 includes a pair of left and right support members 28 and 29, a pair of front and rear vertical columns 11 and 12, and the vertical column 11. , 12 and a wide horizontal frame 13 on which the bottom surfaces of the left and right upper bag bodies 26, 27 are placed are assembled. These are assembled and the front view from the face 3 side is substantially as shown in FIG. It is formed in an inverted U shape.

A plurality of blowers 30 and a manual winch 33 are attached to the gantry 10, and bag body attachment materials 15, 16 are attached to the vertical columns 11, 12, via rubber bands (not shown) provided on the attachment materials 15, 16. The side bags 17 and 18 can be bound together.
Further, a hanger rail 19 is attached to the rear surface of the horizontal frame 13, a plurality of pulleys and a carabiner (both not shown) are attached to the hanger rail 19, and the upper end portion of the central bag body 20 is attached to the hanger rail 19 and suspended. The body 20 is movable along the hanger rail 19.
Further, rod-shaped bag body holding members 24 and 25 are erected at front and rear positions on the horizontal frame 13 and the telescopic wind tube 21, and the upper bag bodies 26 and 27 are accommodated therebetween.

  The protective device mounting base 10 manufactured in this way is as shown in FIG. 5, and the contracted side bag bodies 17 and 18 are bound by a rubber band or the like and attached to one side of the vertical columns 11 and 12. The upper end portion of the central bag body 20 is suspended from the hanger rail 19 and is normally bound to one side. When the upper bag bodies 26 and 27 are deployed, they are deployed on the horizontal frame 13 and the telescopic wind tube 21, and the front and rear surfaces thereof are arranged. It is held by bag holding materials 24 and 25.

The protective device mounting base 10 is large and heavy, and when the bags 17, 18, 20, 26, 27 are attached thereto, the weight further increases. For this reason, when the mounting platform 10 is moved to the mine 2 during excavation work, it is pulled to the mine 2 of the tunnel 1 during excavation using a heavy machine and moved to a predetermined position separated from the face 3.
At this time, since the support members 28 and 29 are formed in a warp shape, the support members 28 and 29 smoothly move on the bottom surface 9 of the mine 2.

Thereafter, the binding of the bag bodies 17, 18, and 20 by the rubber band is released, the manual winch 33 is operated to deploy the bag bodies 17, 18, and 20, and the bag bodies 4b to 4c are appropriately positioned. Air is injected through the blower 30 and the air pressure is adjusted as described above.
Thus, when air is injected into each of the bag bodies 17, 18, 20 and the upper bag bodies 26, 27, the outer peripheral portion of each of the bag bodies 17, 18 presses and closely contacts the inner peripheral surface 2a of the tunnel 1, and the lower end portion thereof is The bottom surface 9 is pressed and brought into close contact with each other, and both side portions of the central bag body 20 are pressed into close contact with the vertical columns 11 and 12.

Then, the opening on the face 3 side of the telescopic wind tube 21 is closed with a partition door 22, and the surface on the face 2 side of one side bag 18 is brought into contact with and held by the wind tube receiving frame 23.
This situation is as shown in FIG. 7, and the face 3 side of the protective device mounting base 10 is closed by the bag bodies 17, 18, 20 and the upper bag bodies 26, 27 deployed at each position.

Under such circumstances, when the working face 3 is blown up, the working face 3 is crushed and a large amount of shear is generated, resulting in explosion sound, blast, stepping stones, dust, rear gas, and the like.
Among them, blast, dust, rear gas, etc. are blocked by the protective device 4 and are prevented from flowing out to the wellhead 5 side, and stepping stones are placed on the face 2 side of each bag body 17, 18, 20 and upper bag bodies 26, 27. The explosion sound that collides with the arranged explosion-proof sheet 7 and falls into the pit 2 on the face 3 side and passes through the protective device 4 in the order of the bags 4a to 4c is stepwise. Attenuated.

The attenuation effect in this case is that the plurality of bag bodies 17, 18, 20 and 26, 27 are formed by superposing the plurality of bag bodies 4b to 4c as described above. Compared with the case of passing, it is improved by 5-8 dB or more.
Moreover, since the air pressures of the bag bodies 4a to 4c are different from each other as described above, the passage resistance of the blasting sound and the blast pressure increases compared to the case where the air pressures of all the bag bodies are made the same pressure. Therefore, the effect of reducing the blast sound and blast pressure is increased.

In addition, with the explosion of the face 3, the opposing surface of each bag 4 a facing the face 3 is pressed and compressed and deformed by receiving a blast or wind pressure, and the displacement acts on the adjacent bag 4 b.
In this case, since the air pressure of the bag body 4b is adjusted to be slightly lower than that of the bag body 4a, the compression displacement of the bag body 4a is smoothly absorbed and buffered, and the tension displacement acts on the adjacent bag body 4c. To do. Further, since the air pressure of the bag body 4c is adjusted to be slightly higher than that of the bag body 4b, the bag body 4b is strongly subjected to tension or compression displacement.
In addition, since the support members 28 and 29 at the lower end are in contact with the bottom surface 9 in the mine and the movement is prevented by the friction force between them, the gantry 10 exhibits a stable protective action.

Thereafter, dust and rear gas staying between the face 3 and the protective device 4 are removed via a wind pipe (not shown), and the scattered dust is removed outside the wellhead 5 after the removal. To do. Then, the air of each bag body 4a-4c of each bag body 17,18,20 and 26,27 is discharged | shrinked, the protection apparatus 4 is prepared for the next operation | work, and it moves to the face 3 side further.
At that time, the protective device 4 smoothly moves by the support members 28 and 29, and after moving forward to a predetermined position, air is injected into each of the bags 4a to 4c, and each of the bags 17, 18, 20 and the upper bag 26, 27 is inflated, and a shielding wall is formed by them, and excavation of the face 3 is resumed.
Then, after a series of excavation operations, the protective device 4 is pulled by a heavy machine and is carried out of the wellhead 5.

  Thus, the tunnel blast noise reduction device of the present invention can be installed in a short period of time without using a large heavy machine, and can be easily removed after installation to promptly resume the excavation work. It is suitable for a tunnel blast noise reduction device because it can prevent leakage and diffusion to the side, and can reduce the blast noise compared to the conventional method and reduce the influence of the blast noise on the surrounding environment.

DESCRIPTION OF SYMBOLS 1 Tunnel 2 Mine 2a Mine inner peripheral surface 3 Face 4 Protection device 4a-4c Bag body 5 Mouth

9 Bottom surface 17, 18 Side bag body 20 Central bag body 23 Frame body 26, 17 Upper bag body

Claims (2)

Blasting sound of a tunnel having a protective device in which a bag body infused with air is installed in a mine separated from the face of the tunnel, and the side peripheral surface of the bag body is installed on the inner surface and the bottom surface of the mine so that the mine can be closed. In the reduction device, the bag body is superposed into three layers and installed, and the air pressure of the bag body disposed on the face side opposite to the face side is set to substantially the same pressure. An apparatus for reducing blasting sound of a tunnel, characterized in that an air pressure of an intermediate bag body is set to be lower than an air pressure of a bag body arranged on the face side or the most well side opposite to the face side . The cross section in the tunnel mine is divided into a plurality of sections, the bags are superposed on each section in three layers, and the air pressure of the intermediate bag is set lower than the air pressure of the bag placed on the face side, The tunnel blast noise reduction device according to claim 1 , wherein the air pressure of the bag body arranged closest to the face side opposite to the face side is set to be higher than the air pressure of the intermediate bag body .

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