CN216405162U - Ceramsite sound absorption metal sound barrier unit - Google Patents

Abstract

The utility model provides a ceramsite sound absorption metal sound barrier unit, which comprises a cavity formed by a metal shell, wherein a cement-based sound absorption plate is arranged in the cavity, and the ceramic sound absorption metal sound barrier unit sequentially comprises the following components in the cavity from the side, facing a sound source, of the metal shell: the first air layer, the first cement-based acoustic board, the second cement-based acoustic board and the second air layer. The utility model realizes the comprehensive improvement of the acoustic performance of the rail transit sound barrier product.

Description

Ceramsite sound absorption metal sound barrier unit

Technical Field

The utility model belongs to the technical field of rail transit noise control, and particularly relates to a rail transit metal sound barrier made of a cement-based sound absorption material and having good durability and excellent environmental protection performance, in particular to a sound barrier plate consisting of a metal shell, a cement-based sound absorption plate and a cavity.

Background

The main noise reduction measure adopted by railways, urban rail transit and the like is to arrange a sound barrier beside a track. Through long-term research, the applicant has developed a ceramsite sound-absorbing board capable of replacing rock wool, polyester fiber and other materials in the existing metal shell, and the ceramsite sound-absorbing board is manufactured by taking ceramsite with different particle sizes as aggregate, cementing materials, additives and the like.

With the intensive research of the applicant, it is found that different ceramsite aggregates and arrangement modes of different ceramsite sound-absorbing plates in the metal shell have different influences on the acoustic effect of the sound barrier product. From the aspect of acoustic effect, sound absorption and sound insulation are two different acoustic concepts and have essential differences. Sound absorption means that incident sound energy is absorbed and consumed by using a sound absorption material or a sound absorption structure, and reflected sound is reduced, so that noise in a volume is reduced. The sound insulation is then to utilize the sound insulation structure to separate the sound and keep off, weakens the transmission of noise, makes noise environment separate with the environment that needs silence, just is the sound arrester commonly used like noise reduction box, sound insulation room, sound proof screen etc. to reach the privacy of guaranteeing indoor environment, reduce the influence of external sound. It can also be seen from the above concept that the sound absorption and insulation process has different objectives and focuses, and the objective of the sound absorption process is to reduce repeated reflection of sound in the room, i.e. reduce reverberant sound in the room, shorten the duration of the reverberant sound, and match with the sound quality design. The sound insulation treatment aims at isolating the transmission of noise from a sound source room to an adjacent room, so that the adjacent room is free from the interference of the noise, namely the background noise is reduced, and the required definition is improved. The sound absorption and the sound insulation are mutually contradictory in nature, the material with excellent sound absorption performance and the sound insulation performance can be very poor, the sound absorption performance and the sound insulation performance are mutually opposite in common acoustic materials, but in the design of the sound barrier of the rail transit, the unification of the sound barrier and the sound insulation performance within a certain excellent range is expected to be realized, which is the design difficulty of the current sound barrier product.

In addition, in the metal sound barrier of rail transit, due to the restriction of the metal shell space and the requirement of overall light weight, the ceramsite sound-absorbing board cannot have a large thickness (generally, the thickness is below 80 mm), the improvement of the sound insulation performance index required by the thin-wall requirement of the ceramsite sound-absorbing board is particularly difficult, and a great effort needs to be made in the technology when the weighted sound insulation quantity is improved by 1 decibel. In railway sound barrier acoustic member products, it is desirable to be able to achieve (weigh) sound insulation above 30 dB.

Disclosure of Invention

The utility model aims to solve the problems in the prior art, and provides a ceramsite sound absorption metal sound barrier unit which has a certain sound absorption effect and sound insulation performance and realizes the comprehensive improvement of the acoustic performance of a rail transit sound barrier product.

The utility model provides the following technical scheme:

the utility model provides a haydite sound absorption metal sound barrier unit, includes the cavity that comprises metal casing, set up cement base acoustic baffle in the cavity, from metal casing is towards sound source one side, includes in proper order in the cavity: the first air layer, the first cement-based acoustic board, the second cement-based acoustic board and the second air layer.

The metal shell can be an aluminum alloy shell and comprises a U-shaped main body, a top section and a bottom section, wherein inwards bent transverse bending parts are arranged on two sides of the top of the U-shaped main body, the top section comprises a transverse web plate, the transverse web plate can cover the inwards bent transverse bending parts arranged on two sides of the top of the U-shaped main body, flanges are vertically arranged on two sides of the transverse web plate of the top section and can be matched and clamped on two sides of the transverse bending parts of the U-shaped main body, a plurality of lower side ribs are arranged below the transverse web plate of the top section and can enter a cavity through gaps between the transverse bending parts of the U-shaped main body to fix a cement-based sound absorbing plate, and the top section can be mutually fixed with the U-shaped main body through rivets arranged on the transverse web plate and the transverse bending parts; the bottom section bar is fixed on the bottom surface in the U-shaped main body, and an upper side rib which can correspond to the lower side rib is arranged on the bottom section bar.

Further, the first cement-based sound absorption plate and the second cement-based sound absorption plate are clamped between the lower side rib and the upper side rib in parallel, and air layers are respectively formed on two sides in the cavity of the U-shaped main body; the side, facing the sound source, of the U-shaped main body is provided with an opening, and the opening rate is 25% -80%, preferably 25% -30%; and shock absorption pads are also arranged on the connecting contact part of the cement-based sound absorption plate and the metal shell and the connecting contact part between the U-shaped main body and the top section.

Wherein, in the cavity, each layer thickness ratio satisfies first air bed: first cement-based acoustical panel: a second cement-based acoustic panel: second air layer ═ (5-38): (35-50): (5-25): (39-72), and the total thickness of the cement-based sound absorption plate is less than or equal to 60 mm.

Wherein the thickness of the single-layer cement-based sound absorption plate is more than or equal to 10mm, preferably more than or equal to 15 mm; the total thickness of the cement-based sound absorption plate is more than or equal to 35mm, preferably more than or equal to 40 mm.

Wherein, two-layer cement base acoustic absorption board thickness ratio satisfies first cement base acoustic absorption board: the second cement-based sound absorption plate is more than or equal to 1.2.

Wherein the thickness of the second air layer is greater than the thickness of the first cement-based acoustic panel, preferably greater than the total thickness of the cement-based acoustic panel.

Wherein, the cement-based acoustic board is made of light aggregate and/or light aggregate ash, a cementing material, an additive and water; the light aggregate is ceramsite with the particle size of 1mm-3mm, and the light aggregate ash is ceramsite ash; the cementing material comprises one or more main materials selected from portland cement, aluminate cement, sulphoaluminate cement, lime, gypsum and water glass, and one or more admixtures selected from fly ash, slag powder, silica fume and volcanic ash; the additive comprises a hydrophobic agent, a water reducing agent, a thickening agent, an air entraining agent and a nano material; in the cement-based acoustic panel, the lightweight aggregate and/or lightweight aggregate ash account for 50% or more, preferably 70% or more, and more preferably 80% or more of the total mass.

Compared with the prior art, the utility model has the advantages and positive effects that: the comprehensive adjustment of the number of layers, the thickness and the air layer of the sound absorption plate enables the metal sound barrier to achieve the optimal uniform sound absorption and sound insulation performance in a limited space, the basic performance index can achieve the compression strength of more than or equal to 2MPa, the breaking strength of more than or equal to 0.7MPa, the surface density of not more than 65kg, the sound absorption coefficient of more than or equal to 0.77 and the weighted sound insulation quantity of more than or equal to 33 dB; the further optimized performance indexes are that the compressive strength is more than or equal to 2.5MPa, the flexural strength is more than or equal to 0.8MPa, the surface density is not more than 65kg, the sound absorption coefficient is more than or equal to 0.8, and the weighted sound insulation capacity is more than or equal to 33 dB. On the premise of achieving the same sound absorption and insulation effect, the weight of the sound barrier is reduced by more than 20% compared with the traditional light aggregate concrete sound barrier. The light aggregate of the utility model selects the ceramsite with the particle size of 1mm-3mm, and does not adopt the particle size of more than 3mm, thereby being capable of improving the aggregate proportion on the one hand, being beneficial to the vibration of the ceramsite on the other hand, being more beneficial to the absorption of sound waves and realizing the reduction of the whole thickness. The cement-based acoustic board is designed in two layers, sound waves are incident into the first cement-based acoustic board through the perforated panel to cause vibration of air among ceramic particles to enable sound energy to be lost, a part of sound waves are incident into the second cement-based acoustic board through the first cement-based acoustic board to better absorb and separate the sound, the transmission of noise is further weakened, then the sound waves penetrate through the double-layer acoustic board to enter a second air layer, the sound is further absorbed and separated, and in the process, the sound waves are repeatedly and constantly reflected and consumed between the double-layer cement-based acoustic board and the air layer. Therefore, the structure and the layout of the utility model solve the contradiction between sound absorption and sound insulation, and achieve the best sound absorption and sound insulation effect.

Drawings

FIG. 1 is a schematic view of the whole structure of a ceramsite sound-absorbing metal sound barrier unit according to the present invention;

FIG. 2 is a schematic cross-sectional structure view of a ceramsite sound-absorbing metal sound barrier unit according to the present invention;

FIG. 3 is a graph of sound absorption coefficient for the products of examples 1-2;

FIG. 4 is a plot of the sound insulation for the products of examples 1-2;

FIG. 5 is a plot of the sound insulation for the product of example 3;

FIG. 6 is a graph of sound absorption for single and double layer cement-based acoustical panels of the same overall thickness;

FIG. 7 shows the sound absorption performance of the same cement-based sound absorption board with and without an air layer;

FIG. 8 is a comparison of sound insulation of a single-layer sound absorbing panel and a double-layer sound absorbing panel with the same total thickness of the cement-based sound absorbing panel;

FIG. 9 is a sound insulation curve for different thicknesses of the second air layer for the same number and thickness of sound absorbing panels;

FIG. 10 is a comparison of sound insulation for a single layer panel and a double layer panel for the same total thickness of cement-based panels.

Wherein 01-a first air layer; 02-a first cement-based acoustic panel; 03-a second cement-based acoustic panel; 04-a second air layer; 1-U-shaped main body; 11-bending part; 12-opening holes; 2-top section bar; 21-a web; 22-flanges; 23-lower rib; 3-bottom section bar; 31-upper rib; 4-shock pad.

Detailed Description

The technical scheme of the utility model is further explained by combining the attached drawings. It is to be understood that the described embodiments are merely exemplary of the utility model, and not restrictive of the full scope of the utility model. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

The cement-based acoustic board is prepared by firing building waste soil, and is prepared from light aggregate and/or light aggregate ash, a cementing material, an additive, water and the like. Wherein the light aggregate is ceramsite with the particle size of 1mm-3mm, and the light aggregate ash is ceramsite ash. Other materials may be selected from existing products. The cementing material can comprise main materials such as portland cement, aluminate cement, sulphoaluminate cement, lime, gypsum, water glass and the like, and admixtures such as fly ash, slag powder, silica fume, volcanic ash and the like; the admixture may include hydrophobing agent, water reducing agent, thickener, air entraining agent, nanomaterial, etc. In the cement-based sound absorption board, the light aggregate and/or light aggregate ash accounts for more than 50%, preferably more than 70%, more preferably more than 80% of the total mass, and the higher proportion of the light aggregate and/or the light aggregate ash is beneficial to improving the density of ceramsite, improving the refraction and scattering of sound waves in the sound absorption board and improving the strength of the board body.

The cement-based sound absorption board can be fixed in a cavity formed by a metal shell, and the cement-based sound absorption board sequentially comprises the following components in the cavity from the side of the metal shell facing a sound source: the first air layer 01, the first cement-based sound-absorbing panel 02, the second cement-based sound-absorbing panel 03 and the second air layer 04. The double-layer sound absorption plate can obviously improve the sound absorption coefficient of a low frequency band, and the air layer can improve the sound insulation quantity of the sound barrier unit and the sound absorption coefficient under certain frequencies. However, the concrete-based sound absorption board is limited by some construction spaces beside the rails, and the space of the cavity in the metal shell is limited to be about 110-140mm, so that the thickness of the cement-based sound absorption board and the thickness of the air layer are restricted, the overall sound absorption and insulation performance of the sound barrier board is obviously improved by reasonably and comprehensively adjusting the thicknesses of the cement-based sound absorption board and the air layer, and the concrete-based sound absorption board and the air layer particularly have the effects of reducing the weight of the sound barrier unit and saving investment.

Fig. 1-2 show an example of a structure of the ceramsite sound-absorbing metal sound barrier unit according to the utility model. The metal shell can be an aluminum alloy shell and comprises a U-shaped main body 1, a top section bar 2 and a bottom section bar 3, wherein inwards bent transverse bending parts 11 are arranged on two sides of the top of the U-shaped main body 1, the top section bar 2 comprises a transverse web 21, the transverse web 21 can cover the inwards bent transverse bending parts 11 arranged on two sides of the top of the U-shaped main body 1, flanges 22 are vertically arranged on two sides of the transverse web 21 of the top section bar 2 and can be matched and clamped on two sides of the transverse bending parts 11 of the U-shaped main body 1, a plurality of lower side ribs 23 are arranged below the transverse web 21 of the top section bar 2 and can enter a cavity through gaps between the transverse bending parts 11 of the U-shaped main body 1 to fix a cement-based sound absorbing plate, and the top section bar 2 can be mutually fixed with the U-shaped main body 1 through rivets arranged on the transverse web 21 and the transverse bending parts 11; the bottom section bar 3 is fixed to the inner bottom surface of the U-shaped body 1 and is provided with an upper rib 31 which can correspond to the lower rib 23. The spacing, number, size, etc. of the lower and upper ribs 23, 31 can be adjusted as desired and/or as the size of the cement-based sound absorbing panel is manufactured. The cement-based sound absorption plate is divided into two layers which can be clamped between the lower side rib 23 and the upper side rib 31 in parallel, and air layers are respectively formed at two sides in the cavity of the U-shaped main body 1. The side of the U-shaped body 1 facing the sound source may be provided with the open hole 12, and the open hole ratio may be 25 to 80%, and the open hole ratio may be preferably set to 25 to 30% in consideration of the overall strength of the metal case and the auxiliary sound absorption of the panel. In order to prevent the sound barrier unit from being rigidly damaged in the processes of vibration, stress concentration, transportation, installation and the like, shock absorption pads 4, such as ethylene propylene diene monomer rubber pads, can be arranged on the connecting contact parts of the cement-based sound absorption plate and the metal shell and the connecting contact parts between the U-shaped main body 1 and the top section bar 2.

According to the utility model, through the research on different arrangement modes of the cement-based sound absorption plate in the limited cavity space of the metal shell, the coordination and unification of sound absorption and sound insulation effects are achieved under the requirement of integral lightweight of the sound barrier unit.

Through a large number of experiments, the utility model discovers that in a limited space, the thickness ratio of each layer meets the requirements of a first air layer: first cement-based acoustical panel: a second cement-based acoustic panel: second air layer ═ (5-38): (35-50): (5-25): (39-72), when the total thickness of the cement-based sound absorption plate is less than or equal to 60mm, the sound absorption and the sound insulation can be optimized and unified, the sound absorption coefficient can reach more than 0.77, and the weighted sound insulation quantity can reach more than 33 dB. Meanwhile, the total thickness of the cement-based sound absorption plate is designed in consideration of the requirement of light weight.

The cement-based sound absorption plate is preferably designed into two layers, under the condition that the total thickness is limited, the strength is easily low due to the three or more layers, and the thickness of the single-layer cement-based sound absorption plate is preferably more than or equal to 10mm, more preferably more than or equal to 15 mm; the total thickness of the cement-based sound absorption plate is more than or equal to 35mm, and more preferably more than or equal to 40 mm. The product of the utility model has the compression strength of more than or equal to 2MPa, the breaking strength of more than or equal to 0.7MPa and the surface density of not more than 65kg, and realizes further lightweight improvement compared with the non-optimized standard (the compression strength of 2MPa under the condition of 70kg of surface density).

Wherein, first cement based acoustic panel: the second cement-based sound absorption plate is more than or equal to 1.2, so that the first cement-based sound absorption plate has larger thickness, can absorb sound effectively under the larger thickness, and can reduce the thickness and promote the matching sound insulation with an air layer through the supplement sound absorption of the thinner second cement-based sound absorption plate. The thickness of the second air layer is preferably larger than the thickness of the first cement-based sound absorption plate, the thickness of the second air layer is more preferably larger than the total thickness of the cement-based sound absorption plate, the design of the thickness of the second air layer is beneficial to effectively dissipating sound waves penetrating through the cement-based sound absorption plate, the defect of insufficient sound insulation capability of the cement-based sound absorption plate with the corresponding thickness is made up, and the sound insulation effect is improved. Under the optimized conditions of the layer number and the thickness, the sound absorption and insulation effect of the utility model is further improved, and the sound absorption coefficient is more than 0.8, the weighted sound insulation capacity is more than 33dB, the compressive strength is more than or equal to 2.5MPa, and the flexural strength is more than or equal to 0.8 MPa.

Some examples and comparative examples of the metallic sound barrier unit of the present invention are shown in table 1, and other preparation conditions of each example and comparative example are the same.

TABLE 1

3-4 take examples 1-2 as examples respectively, show the sound absorption coefficient curve and sound insulation curve of the product, and it can be seen that the product of the utility model can produce effective sound absorption and sound insulation effects under different frequency ranges. Fig. 5 shows the sound insulation curve of example 3 alone, which is consistent with the trends of examples 1-2, with better sound insulation performance at higher frequency bands. Fig. 6 shows sound absorption curves of the single-layer and double-layer cement-based sound absorbing panels at the same total thickness, and it can be seen that the difference in sound absorption coefficient is not great at the low frequency range and the double-layer cement-based sound absorbing panel has a superior sound absorbing effect at the higher frequency range. Fig. 7 shows the sound absorption performance of the same cement-based sound absorption panel with an air layer (example 4) and without an air layer (air layer thickness is 0), and it can be seen that the sound absorption coefficient of the sound barrier in the low frequency range can be effectively improved by the air layer. Fig. 8 shows the comparison of the sound insulation amount (without air layer) between the single-layer sound-absorbing panel and the double-layer sound-absorbing panel for the same total thickness (50mm) of the cement-based sound-absorbing panel, and it can be seen that the sound insulation performance can be effectively improved by the double-layer sound-absorbing panel. Fig. 9 shows the sound insulation curves of the same number and thickness of the sound-absorbing panels and different thicknesses of the second air layer, and it can be seen that, in the design of the double-layer sound-absorbing panel, the sound insulation performance of the second air layer in the middle frequency range can be effectively improved by increasing the thickness of the second air layer, and the difference of the sound insulation performance of the double-layer sound-absorbing panel in the low and high frequency ranges is small. Fig. 10 shows the comparison of the sound insulation amounts of the single-layer sound-absorbing panel and the double-layer sound-absorbing panel (the first air layer is not provided, and the thickness of the second air layer is 47.5mm) with the same total thickness of the cement-based sound-absorbing panel, and it can be seen that the sound insulation performance is improved when the second air layer is provided compared with when the air layer is not provided (fig. 8), and the difference of sound insulation of the double-layer sound-absorbing panel compared with that of the single-layer sound-absorbing panel is reduced. In view of fig. 3 to 10, it can be seen that the sound absorption and insulation effects are simultaneously influenced by the number of layers, thickness, and air layer of the sound absorption plate, and particularly, the adjustment of each factor is influenced and restricted within the total installation space limit.

Examples 1 to 8 in table 1 show that the thickness ratio of each layer satisfies the first air layer using the present invention: first cement-based acoustical panel: a second cement-based acoustic panel: second air layer ═ (5-38): (35-50): (5-25): (39-72) total thickness of the cement-based acoustic panel of 60mm or less. It can be seen that in a limited space, the sound absorption coefficient and the weighted sound insulation amount of the metal sound barrier plate reach target optimization indexes, and meanwhile, the strength performance is effectively improved.

Example 6 includes the above design conditions of each layer of the present invention, and additionally provides a 10mm cement-based sound-absorbing panel (3mm to 5mm of ceramic particles) before the first cement-based sound-absorbing panel, and appropriately reduces the thickness of the second air layer (47.5mm), it can be seen that the sound absorption and sound insulation performance is maintained under the conditions of the present invention, but the 10mm cement-based sound-absorbing panel has a small thickness, and the flexural strength is reduced (0.8 MPa). Meanwhile, the thickness of the second air layer is slightly reduced and is not more than the total thickness of the sound absorption plate, and the sound insulation performance is also slightly reduced (33 dB).

Embodiment 7 provides an example of adjusting the thickness of two layers of cement-based sound-absorbing panels, and the first cement-based sound-absorbing panel is slightly thicker than the second cement-based sound-absorbing panel, but does not satisfy the difference of more than 1.2 times, and the sound-absorbing coefficient is slightly reduced, and does not reach the optimized index of more than 0.8.

Example 8 provides a smaller total thickness (35mm) of two-layer cement-based acoustical panel, and due to insufficient panel thickness, although the weight reduction index was optimized, the acoustical absorption coefficient was slightly reduced, and the optimized index was not reached to 0.8 or more, and the flexural strength was also reduced.

Comparative example 1 provides two equal air layer thicknesses (41.5mm), and it can be seen from fig. 9 that the second air layer thickness is too low to effectively dissipate sound waves, and at the same time, the sound insulation effect is affected and the sound absorption and insulation performance is reduced.

Comparative example 2 and comparative example 3 each use a single layer of cement-based acoustical panel, and the thickness of the two air layers was different. It can be seen from comparative example 2 that, in the case of optimizing the thickness of the second air layer, although the sound absorption and insulation performance is improved compared with that of comparative example 3 in which the air layer is not optimized, the performance index of the double-layer cement-based sound absorption board is still not better, and the sound insulation performance cannot meet the index requirement (32 dB).

Comparative example 4 provides a cement-based sound-absorbing panel with the same thickness of three layers, although the total thickness is not changed and the difference of sound-absorbing performance is not great, the sound-insulating performance cannot meet the index requirement (32dB) because the layering is more and the thickness of the first cement-based sound-absorbing panel is reduced, and the strength index is also obviously reduced.

Comparative example 5 a layer of air layer of 10mm was added between two layers of cement-based sound absorbing panels, and at the same time, the thickness of the second cement-based sound absorbing panel was increased, and although the sound absorption coefficient was improved, the sound insulation performance was further decreased, indicating that even if an air layer was added in the middle, the problems of the second cement-based sound absorbing panel being too thick and the second air layer being not thick enough could not be improved.

The scope of the present invention is not limited thereto, and any person skilled in the art can easily make changes or substitutions within the technical scope of the present invention, and the present invention is covered thereby. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (11)

1. The utility model provides a haydite sound absorption metal sound barrier unit, includes the cavity that comprises metal casing, its characterized in that, set up cement base acoustic baffle in the cavity, certainly metal casing is towards sound source one side and is gone up, includes in proper order in the cavity: a first air layer (01), a first cement-based sound absorption plate (02), a second cement-based sound absorption plate (03) and a second air layer (04);

the thickness ratio of each layer satisfies the first air layer: first cement-based acoustical panel: a second cement-based acoustic panel: second air layer ═ (5-38): (35-50): (5-25): (39-72).

2. The ceramsite sound absorption metal sound barrier unit according to claim 1, wherein the metal shell is an aluminum alloy shell and comprises a U-shaped main body (1), a top section bar (2) and a bottom section bar (3), wherein two sides of the top of the U-shaped main body (1) are provided with inward-bent transverse bending parts (11), the top section bar (2) comprises a transverse web (21), the transverse web (21) can be covered on the inward-bent transverse bending parts (11) arranged on two sides of the top of the U-shaped main body (1), two sides of the transverse web (21) of the top section bar (2) are vertically provided with flanges (22) which can be matched and clamped on two sides of the transverse bending parts (11) of the U-shaped main body (1), a plurality of lower side ribs (23) are arranged below the transverse web (21) of the top section bar (2), and can enter into the cavity through gaps between the transverse bending parts (11) of the U-shaped main body (1), the top section bar (2) can be mutually fixed with the U-shaped main body (1) through rivets arranged on the transverse web plate (21) and the transverse bending part (11); the bottom section bar (3) is fixed on the inner bottom surface of the U-shaped main body (1), and is provided with an upper side rib (31) which can correspond to the lower side rib (23).

3. A ceramsite sound-absorbing metal sound barrier unit according to claim 2, wherein the first cement-based sound-absorbing board (02) and the second cement-based sound-absorbing board (03) are clamped between the lower side rib (23) and the upper side rib (31) in parallel, and air layers are respectively formed at two sides in the cavity of the U-shaped main body (1); one side of the U-shaped main body (1) facing the sound source is provided with an opening (12), and the opening rate is 25% -80%; and a shock absorption pad (4) is also arranged on the connecting contact part of the cement-based sound absorption plate and the metal shell and the connecting contact part between the U-shaped main body (1) and the top section bar (2).

4. A ceramsite sound-absorbing metal sound barrier unit according to claim 3, wherein the side of the U-shaped body (1) facing the sound source is provided with openings (12) with an opening ratio of 25-50%.

5. The ceramsite sound-absorbing metal sound barrier unit according to claim 1, wherein the total thickness of the cement-based sound-absorbing board is less than or equal to 60 mm.

6. The ceramsite sound-absorbing metal sound barrier unit according to claim 1, wherein the thickness of the single-layer cement-based sound-absorbing plate is more than or equal to 10 mm; the total thickness of the cement-based acoustic board is more than or equal to 35 mm.

7. The ceramsite sound-absorbing metal sound barrier unit according to claim 6, wherein the thickness of the single-layer cement-based sound-absorbing plate is more than or equal to 15 mm.

8. The ceramsite sound-absorbing metal sound barrier unit according to claim 6, wherein the total thickness of the cement-based sound-absorbing board is more than or equal to 40 mm.

9. The ceramsite sound-absorbing metal sound barrier unit according to claim 1, wherein the first cement-based sound-absorbing panel: the second cement-based sound absorption plate is more than or equal to 1.2.

10. The ceramsite sound-absorbing metal sound barrier unit according to claim 1, wherein the thickness of the second air layer is greater than the thickness of the first cement-based sound-absorbing panel.

11. The ceramsite sound-absorbing metal sound barrier unit according to claim 1, wherein the thickness of the second air layer is greater than the total thickness of the cement-based sound-absorbing panel.

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