The basic definition of sound wave propagation process, encountered the sound barrier, it will happen reflection, transmission and diffraction three phenomena. Usually we think that the barrier can prevent the spread of the direct sound, and the attenuation of the transmitted sound enough, while transmitting the sound effects are negligible. Therefore, sound effects sound barrier is generally the amount of noise reduction can be said that it reflects the sound through the sound barrier to shield the two skills. Between the sound source and the receiving point to insert a sound barrier, set up a barrier of infinite length, acoustic diffraction past only from the top of the barrier, and in the subsequent formation of an acoustic shadow zone, as the light is blocked as the formation of a shadow object. In this acoustic shadow area, people can feel the noise significantly reduced, and this is the sound barrier noise reduction. Classification structure sound barrier classified into traffic barriers, equipment noise attenuation barriers, industrial plant boundary noise barrier application environment based on sound barrier, sound barrier. Sound Barrier Material classification can be divided into the following categories: metal sound barrier (metal louvers, metal mesh holes), concrete sound barrier (lightweight concrete, high strength concrete), PC sound barrier, fiberglass sound barriers. 2.7 meters wide, the widest pc plexiglass plate steel production has now become in Wuxi, the sound barrier plant installation is successful, greatly improve the visual and noise effects according to different uses can be divided into several categories: sound barrier rail, highway sound barriers, city Landscape sound barrier, neighborhood noise reduction barriers. Outdoor sound barrier sound barrier structure generally use brick or concrete structures, interior sound barrier cited steel, wood ,, PMMA / POLYCARBONATE SHEET pull plastic, gypsum board and foam aluminum structure. Sound barrier consists of two parts, steel columns and suck insulation panel composed of members column is the main force of the sound barrier, it is fixed by bolts or welding on the road side of the barrier wall or rail embedded steel; absorbing insulation acoustic absorption panels are the main component, it is through high-strength spring clamp to secure it in the H-type column groove to form the sound barrier. Sound barrier has been designed to more fully consider the elevated highway, crash safety urban light rail, subway wind load, transport vehicles and all-weather outdoor corrosion problems. It is nice shape, producing exquisite, easy to transport, install, low cost, long life, especially for the elevated highway and city rail, subway use anti-noise, is a modern city facilities ideal acoustic noise. Sound barrier height 5m 1m a room, covering the regional average effective noise reduction up to 10 ~ 15dB (A) (125Hz ~ 40000Hz, 1/3-octave) and up to 20dB (A). Generally speaking, the higher the sound barrier, or farther away from the sound barrier, noise better. Series introduces a constant basis sound barrier aluminum fiber cotton series of constant underlying sound barrier aluminum fiber cotton Specifications: 30mm thick noise reduction coefficient NRC = 0.85 absorbing sound barrier constant basis Rockwool Rockwool series of constant basis Features a sound barrier, insulation performance: thermal insulation properties Good is the basic characteristic of wool products, and at room temperature conditions (about 25 ℃) thermal conductivity of rock wool is usually between 0.03 ~ 0.047W / (moK). 2, combustion performance: rock wool, slag wool products of combustion performance depends on how many of the flammable adhesive. Rockwool itself belongs to inorganic mineral fibers, non-combustible, in the course of processing into products, and sometimes adding organic binders or additives, which will have some impact on the performance of the products of combustion. 3, noise performance: rock wool products have excellent sound insulation and sound absorption properties, their absorption mechanism is such articles having a porous structure, when the sound waves, the effect of the flow resistance due to friction, so that part of the acoustic energy fiber absorbed, overcast hinder the transfer of sound waves. Hang wool base sound barrier applications: Rockwool since the 1970s is widely used in construction and industrial equipment, pipes, furnace insulation, fire, acoustic, seismic, metallurgy, machinery, building materials, petroleum, chemical and other industries. Rockwool products are mainly technical performance of high-strength cement cement-based lightweight composite acoustic sound absorption sound barrier: lightweight, high strength cement absorption soundproof board adopts advanced technology and raw materials to produce efficient sound absorption products, technical performance in the domestic advanced level. Structure types, beautiful appearance. Designed to meet different requirements, widely used in highways, railways, viaducts and industrial plant boundary noise control engineering. Technical indicators technical indicators sound insulation sound insulation sound absorption coefficient absorption coefficient of sound absorption of aluminum composite sound-absorbing aluminum folding pinhole Features: light pollution, glare, anti-aging, shock, freeze-thaw resistance, sound absorption coefficient stability, resistant to moisture, corrosion-resistant, easy to bend easy processing, easy to transport, disassembly, easy maintenance, reasonable price, and painted in different colors. Pinhole aluminum complex sound technical parameters: 1, noise reduction coefficient: 75MM when the cavity NRC≥0.70; 2, sound insulation: ≥30dB (A); 3, artificial accelerated weathering (250h): No chalking; 4, resistance to salt spray Corrosion: Acidic 1000h, appearance rating 10, no pitting, blistering, peeling and other corrosion; 5, tensile load: ≥1305N; 6, fire rating: A-level or perlite is a thin slab of sound absorption hole, inorganic cement composition which does not contain contaminants, basic is cement, natural minerals together with other chemical materials through a special post-treatment, stirring to molding, so durable, and very high plasticity, may be formulated in different bulk density, shape, color, appearance to suit different conditions of installation and design, to meet the different needs of practical application. Compared with other existing sound-absorbing insulation materials, perlite material has the following characteristics: perlite sound barrier with stable absorption properties, noise reduction coefficient NRC0.85 around, in the high-frequency noise is good sound absorption performance sector, in line with the road acoustical sound barrier requirements. Application and simple to install, can be prefabricated or site-forming. No organic ingredients, non-polluting ingredients: for example, asbestos, mineral fibers, polystyrene, cellulose, non-absorbent, anti-wind and rain erosion, easy to clean and can be used in outdoor environments exposed, durable and strong, natural anti-aging. Low density, high temperature, low temperature, acid, alkali erosion and fire. Acoustic sound absorption frequency bandwidth, noise reduction coefficient around NRC0.85, insulation capacity 46dB. Soft colors, color multiple choice, nice, continental style. Orifice sound absorbing micro-perforated plate is in principle a certain number of holes drilled plate after plate to leave some air layer, so that the incident sound wave resonance absorption, so as to achieve sound absorption effect. Micro-perforated plate sound barrier has been widely used in highways, urban elevated and other places. Micro-perforated plate material from the earliest PC board, acrylic board, the development of color steel, aluminum and other metal materials. Advantages of micro-perforated plates are: high temperature, moisture resistance, impact resistance, high-speed airflow. With stable absorption properties, the average absorption coefficient greater than 0.60, noise reduction coefficient around NRC0.60, in line with the road noise barrier acoustic requirements. Sound-absorbing composite wood sawdust cement acoustic absorption panels are made of a special process through a series of wood, cement and chemical additives, has excellent noise absorption properties, high strength, weather resistance, long life, can meet different design and requirements, can be composed of a variety of structural forms, is to control traffic noise, an ideal material for industrial noise, residential park noise. Cement wood composite acoustic panels wood composite cement absorption coefficient absorption coefficient of acoustic panels a PC board, the mechanical properties of the sound barrier for a PC board, impact strength: PC sheet with excellent impact resistance, which is higher than traditional glass 250 times, 30 times higher than the acrylic sheet. The impact strength of polycarbonate panels Pc's like saying "transparent plate," said. 2, good tensile strength, PC solid sheet heat resistance, even at 120 ℃, its tensile strength is still up 350kgf / cm2. 3, bending strength: PC solid sheet bending is good, even if the bending angle up to 90 °, still broken. 4, anti-fatigue and creep resistance: PC solid sheet creep resistance is the best in the thermoplastic plastic. Creep even at high temperatures is still very small. Second, the thermal properties of the sound barrier for a PC board, shaped melting temperature: PC solid sheet melt-shaped temperature 135 ℃, its continuous use temperature of 120 ℃. 2, linear expansion coefficient: linear expansion coefficient of 7 × 10-5cm / cm / ℃ smaller in the case of the plastic. 3, brittle transition temperature: PC solid sheet brittle transition temperature of -40 ℃, the minimum continuous use temperature -30 ℃, is generally not comparable plastic. 4. Burning: PC solid sheet of self-extinguishing plastic is a flame retardant, it does not produce toxic fumes when heated to high temperatures. 5, the thermal conductivity: PC solid sheet of thermal conductivity and general plastic insignificant, 1/4 glass, 1/300, 1/1000 aluminum, copper, iron 1/2000, is excellent insulation properties of materials one. Third, the optical properties of the sound barrier in a dedicated PC board, light transmittance: PC solid sheet of translucent glass was fairly between 85-90%. 2, weather resistance: general long-term exposure to outdoor PC endurance plate, by ultraviolet radiation can lead to yellowing and surface deterioration. Gao Feng PC sheet surface with a layer of anti-UV layer, even if long-term exposure to outdoor, optical and mechanical properties did not change significantly. Fourth, the sound barrier for the PC board polycarbonate chemical resistance properties at room temperature, good resistance to weak acid and alcohol, but the performance of the resist strong acid, benzene, chlorinated hydrocarbons and esters slightly poor, easy to produce dissolution, swelling or decomposition of the phenomenon. Because of its chemical resistance and low temperature, the internal residual stress magnitude and length of time of exposure, it should pay particular attention before use. Five, lightweight PC board dedicated sound barrier at the same thickness and size, PC solid sheet is only half the weight of glass, so you can save a lot of difficulty handling and sound barrier construction. Six, sound effects sound insulation sound barrier dedicated PC board PC sheet is higher than the glass 3-4DB, the preferred material for noise barriers transparent material, PC solid sheet has been widely used in highway sound barrier, sound barrier viaduct, Freeway sound barrier, sound barrier rail, rail sound barriers, high iron sound barrier, sound barrier noise barriers residential projects. Centrifugal glass wool glass wool (GALSS WOOL) is on the rise internationally eighties new insulation materials, glass fiber is a new member of the family, it uses the world's most advanced centrifugal blowing process, the glass in a molten state Fibrosis and spraying cotton-like material made from thermosetting resin, and then after thermal curing deep processing series of products can also be made with a variety of uses. It has a flame-retardant, non-toxic, corrosion resistance, bulk density of small, low thermal conductivity, chemical stability, low moisture absorption, good hydrophobicity and many other advantages, is now recognized as the most superior performance of thermal insulation, sound-absorbing material, has a very wide range of uses. Board with this material, felt, pipe insulation have been widely used in construction, chemical, electronics, electricity, metallurgy, energy, transportation and other areas, sound absorption, the effect is very significant. Because this material is soft, fine fiber, low shot content, construction will not irritate the skin, and thus by construction units welcome, becoming the first choice of insulation. Glass wool products are quartz sand, feldspar, silica sodium borate as the main raw material, high temperature melting cotton-like fiber obtained less than 6μm then by heat setting to create a variety of shapes, sizes products. Product Features: 1, light weight, sound absorption coefficient, flame retardant and has excellent chemical stability. 2, moisture, radiation. Specifications Specifications Application: 1, roof insulation, cold, sound-absorbing materials. 2, building insulation, cold. 3, entertainment theaters, television stations, radio stations, laboratories, acoustic treatment. 4, petroleum, chemical, thermal, industrial heating, heating and other civilian pipe insulation, cold. Aluminum foam is made of aluminum foam additive after the aluminum or aluminum alloy, after the foaming process is made with both the metal and the bubble characteristics, is a new type of porous sound-absorbing material. Aluminum foam acoustic panels and aluminum fiberboard are directly exposed to the atmosphere does not need armor and fillers such as perforated plate for easy installation. Aluminum foam sound barrier with stable absorption properties, the average absorption coefficient greater than 0.64, noise reduction coefficient around NRC0.75, mainly for low-frequency sound absorption performance of outstanding traffic noise, higher than some of the other common sound-absorbing material, and in After the rain and dust absorption, the absorption coefficient does not change, in line with the road noise barrier acoustic requirements. Aluminum foam acoustic panels can be painted in different colors, and sound absorption performance is not affected, can greatly enrich the sound barrier landscape. Aluminum foam acoustic panels and glass can be washed like, and can be achieved through natural self-cleaning rain, will not affect the acoustic performance; once fouling, does not affect the acoustic performance, but will improve the performance of high-frequency sound absorption. Aluminum foam with a metal corresponding fire resistance, weather resistance, corrosion resistance, aging resistance, the design life of 20 years. Aluminum foam acoustic panels have good anti-glare properties. Aluminum foam sound barrier has been widely used in China, the Lupu Bridge, Xuputaiqiao, A5 highway, Spring Road Viaduct are applied aluminum foam, and has passed inspection. Outer Ring Road Pudong section of Shanghai city is also being applied to install. Aluminum fiber fiber acoustic board is made of aluminum aluminum mesh on both sides of the mat and aluminum foil sandwiched between which, by roll forming a metal type sound-absorbing material. It has excellent sound absorption properties, high tensile strength, ultra-thin lightweight, easy to transport and storage, good weather resistance, decorative, easy processing and construction and installation, recyclable and so on. ● thin light: aluminum fibers absorbing plate thickness is generally about 0.8 ~ 2.0mm, the surface density of 1.4 ~ 3.2kg / m2. Due to a very small volume of material, transportation is very convenient storage. ● 1.35mm thick noise reduction coefficient NRC for noise reduction coefficient NRC 0.7,1.8mm thick as 0.9 ● decorative: the board can be sprayed desired color, rich colors and beautiful, set decoration effects and sound-absorbing effect in one. ● Easy processing and construction and installation: Plate good processability, easy drilling, bending and cutting. Construction and installation process does not produce fiber scattering dust pollution affecting the health of workers, the construction is simple. ● Material Board Size Large: aluminum fiberboard is through the use of the plastic roll forming, plate width large. In addition to the plate, can be processed into a variety of shapes of the absorber. ● recyclable: the material is aluminum metal, discarded garbage swap does not form on the environment pollution, so it is an environmentally friendly product itself. Factors such as the frequency of the distance, the barrier height and the sound source and the receiving point of the noise barrier noise sound barrier between the amount of noise related. A large component of the relationship between sound and noise reduction and noise barrier frequency of greater than 2000Hz frequency sound than the noise reduction of about 800 to 1000Hz IF sound better, but for around 25Hz low-frequency sound. Because the acoustic wavelength is relatively long and easily diffracted from the top of the barrier in the past, so the effect is poor. Typically, high-frequency sound sound barrier can reduce l0-15dB. The height of the sound barrier, according to the height of doubling the distance between the sound source and the receiving point of the design, barrier, then the noise increase the amount of 6dB, in order to make better noise barrier, should be so close to the sound barrier source or receiving point. Sonic type 1. infrasonic and ultrasonic sound waves can cause hearing people to mechanical waves called acoustic wave (audio). Frequency between 20 ~ 20000Hz. 2. infrasonic frequencies below 20Hz are called mechanical waves infrasound. The ultrasonic frequencies above 20000Hz mechanical ultrasonic. 1. shear wave longitudinal wave longitudinal wave propagation medium along the direction of motion of the particle wave. 2. Medium-wave particle is perpendicular to the propagation direction of the wave motion. 3. The surface wave propagation along the surface layer of the medium, the amplitude of the wave weakened rapidly with depth. 1. spherical wave wave cylindrical wave plane wave fronts of the wave propagation direction perpendicular to the plane of the county. 2. cylindrical wave wavefront wave coaxial cylinders. 3. spherical wave wavefront concentric spherical waves. Selection principles of sound barrier material selection, the general principle is good noise reduction performance, the structure safe, reliable, affordable materials, low installation cost, durable, long life, landscape coordination, nice and so on. Specifically as follows: (1) a large amount of noise: the average amount of noise should not be less than 35dB; (2) the sound absorption coefficient is high: the average absorption coefficient should be not less than 0.84; (3) weather Durability: The product should have a water resistance heat, UV, temperature changes will not degrade the performance of stormwater quality or abnormal. Products using aluminum coil, galvanized coil, glass wool, H galvanized steel column surface outside the grounds of anti-corrosion life of more than 15 years. (4) appearance: choose a variety of colors and shapes are combined, coordinated with the surrounding environment, the formation tapestry. (5) Economy: prefabricated construction, improve work efficiency, shorten construction time, saving construction costs and labor costs. (6) Convenience: parallel with other products to install, easy to maintain, easy to update. (7) Light: acoustic panels series has the characteristics of light weight, reduce the load bearing elevated light rail, elevated road, can reduce the cost structure. (8) Fire: The superfine wool, because of its high melting point, non-flammable, fully meet the requirements of environmental protection and fire code. (9) High intensity: a combination of different regions of the climatic conditions, structural design fully into virtual wind loads. Increase the strength of the recess by pressing production line. (10) waterproof, dustproof: material designed to fully consider the waterproof, dustproof, dust or rain environment in its sound absorption performance is not affected, construct drainage measures have been set for dust, avoid stagnant water inside components. Resonant cavity micro-perforated sound absorption in the rain sound absorption performance is not affected environment for low-frequency noise is particularly evident. (11) Durable: product design has been fully taken into account wind load road transport vehicle crash safety and full gas fake outdoor corrosion. Products using aluminum coil, galvanized coil, glass wool, H galvanized steel column surface. No corrosion within the warranty period, the same type, sound absorption, sound insulation effect is not reduced. Advantages prospects a low cost: not only low production cost, light weight and because the product can significantly reduce the load bearing elevated light rail, elevated road, reduce project cost; two, to withstand wind load strength: high strength, light weight, can meet our various different climatic conditions of the region for wind load requirements; 3, superior acoustic performance: average noise magnesite sound barrier is greater than 35dB, the average absorption coefficient greater than 0.84 in all areas to meet the requirements of the sound barrier; 4, fire performance: Ling magnesium cementitious material is a non-combustible inorganic materials, composite acoustic glass wool, perlite and other materials also have good fire performance, making the product has excellent fire performance, is a national Class A non-combustible material; 5, the use durability: Magnesite sound barrier waterproof, fire-resistant, corrosion-resistant, anti-UV, from rain, snow, wind and sand erosion and other inclement weather, long life; 6, easy to install: Magnesite sound barrier, light weight, can be fabricated construction, high efficiency short duration, can save a lot of labor costs; 7, aesthetic plastic: Depending on the needs of the metal material structure can form and translucent material combinations can also be painted in different colors and patterns to meet the requirements of decorative landscape. 8, energy saving and environmental protection: the sound barrier magnesite raw materials used non-toxic, and the production process without high heat, no toxic gas release, the state encourages the development of environmentally friendly products; 9, broad scope of application: Depending on the needs of machine production Ling soundproof panels and magnesite magnesium acoustic panels, suitable for road transportation, rail, railway, culverts, tunnels, and various industrial plants, workshops and residential quarters, and other fields. With the prospect of China's rapid economic development, accelerating urbanization, highways, railways, urban rail transit and other modes of transportation to get rapid development in the construction of these roads would inevitably have to pass through the population is concentrated residential areas, the resulting traffic road noise to nearby residents to work, live, learn to bring a certain amount of interference. National environmental monitoring results show: road traffic noise, about 17 percent of the city are moderately polluted, 49% of urban light pollution, establish sound barrier solve the traffic noise pollution has become the main form of urban road noise control. Magnesite sound barrier because of its unique advantages of rapid development, has been widely used in Beijing, Zhengzhou, Guangzhou and Chongqing and other cities. Application introduced mainly for sound barriers along the railway and highway sound barrier is mainly used for highways, elevated roads composite, S-Bahn subway and other transportation facilities in the municipal acoustic noise, control the impact of traffic noise on nearby urban areas, can also be used in factories and other noise sources acoustic noise. Divided into pure sound barrier sound barrier reflective insulation, sound insulation and sound absorption with a combination of complex sound barrier, which is more effective insulation made out of. Most of the sound barrier have chosen hybrid sound absorption and insulation products, this type of product is characterized by the generation and transfer characteristics of the targeted road noise control. Such as car and road friction sound or locomotive and rail grinding sound in the lower road, the sound through the upper body of the screen there is the characteristic diffraction, so the use of the upper and lower sound absorption in the design, construction noise in the middle, so you can effectively decrease the noise around shoot; middle sound barrier reflective insulation transparent plate, can effectively interrupt transmission of sound waves; while also providing a broad perspective environment for drivers and residents. Architectural acoustics, through acoustic treatment, control the reverberation time and indoor acoustic environment, to meet the requirements of professional knowledge to use a stadium, diffraction sound barrier over the top sound by sound diffraction reach the point of energy can be smaller than the direct sound when there is no barrier. Difference between the direct sound and the sound level of the diffracted sound, called diffraction attenuation, the value represented by the symbol △ Ld, and with Φ angle increases. Sound barrier diffraction sound attenuation is the sound source, the sound of the three points with a sound barrier function of the geometry and frequency by, it was decided to screen two acoustic, acoustic transmission source to spread through the sound emitted by the sound barrier phenomenon points . Acoustic energy through the sound barrier depends on the surface density of the sound barrier, the angle of incidence and frequency of sound waves. The ability to evaluate the sound barrier insulation with sound transmission loss TL. TL large, the transmitted acoustic energy small; TL small, the transmittance of a large acoustic energy, the acoustic energy transmitted sound barrier can reduce insertion loss, reducing the amount of insertion loss due to transmission is called transmission acoustic correction amount. ΔLt symbols represent. Typically acoustic design, it is required TL - △ Ld≥10dB, acoustic energy can be transmitted at this time is negligible, i.e., △ Lt≈0. 3, reflection on both sides of the road were built when the sound barrier, and the sound barrier parallel, the sound waves will be multiple reflections between the sound barrier, sound barrier over the top by sound diffraction to the point, it will reduce the insertion loss of the sound barrier by reduce the amount of reflected sound wave caused by the insertion loss is called the reflected acoustic correction amount represented by the symbol △ Lr. To reduce reflected sound, usually in the side of the road sound barrier by additional sound-absorbing structure. Depends on the size of the reflected acoustic energy absorption coefficient of the sound absorbing structure α, which is a function of frequency, the sound absorbing structure for evaluating the overall sound barrier absorption effect, commonly used noise reduction coefficient NRC. Insertion loss of main physical barrier. Construction Requirements 1. embankment built on the basis of sound barrier should be synchronized with the construction of roadbed, not because of its construction and damages, roadbed stability and security. Foundation construction should sound barrier in the road after the basic body shape, before laying the track and cable trench construction; before construction on the embankment should identify the location of all types of pipeline; based on the basis of the size and location of the sound barrier on the hard shoulder grooving cut, cut open When the tank is prohibited destruction of various types of pipelines. 2. The basic design requirements should sound barrier position, shape, size, depth, construction, foundation excavation subgrade surface shall not be destroyed. 3. Sound Barrier foundation laying anchor, anchor hole grouting materials used in construction, construction methods should be consistent with the design requirements, shall not affect the security and stability of the roadbed. The foundation design requirements should sound barrier construction joints. The foundation of every sound barrier 20m ~ 30m long set an expansion joint. Construction should be combined with the location of the site topography to determine the specific joints. 5. sound barrier design requirements should be embedded foundation drains, drain outlet shall scour the roadbed; and non-ballasted track line between the sump drain at the intersection of concrete foundation may destroy drain. Each top 2m embedded foundation ?100mmL shaped PVC pipe to the inside of the shoulder drainage sound barrier surface; variable cross-section at the middle of each base by 2% slope 4m embedded ?75mm straight PVC pipe to drain water seepage and primitive way cable channel drain ; among non-ballasted track roadbed wire line connections sump drains in the foundation can be poured. Roadbed sound barrier drainage facilities should be located, outside of the drain outlet should avoid generating embankment slope erosion and prevent sound leakage. 6. After all the sound barrier with the pouring of concrete foundation dense, its surface smooth surface should converge with the roadbed. 7. Sound Barrier foundation concrete strength tests shall comply with the provisions of Article 11.2.18 Standard. 8. sound barrier base and cable ducts, catenary between the pillars, and the shoulder surface cracks etc design requirements should be applied waterproof layer. Foundation and cable trays, catenary between the pillars, and the shoulder surface cracks etc do waterproof layer of asphalt concrete applications. 9. sound barrier line basis from the centerline, cross-sectional dimensions, buried depth of tolerance, the number of tests and test methods should be consistent with the requirements of Table 13.4.9. Table sound barrier line basis from the centerline, cross-sectional dimensions, buried depth of tolerance, the number of tests and test methods tolerance test item construction unit test method a number of tests from the line centerline position 0, + 20mm basis by the sound barrier 10% of the number of samples tested 2-sectional dimensions measuring tape measuring tape 3 ± 20mm depth of not less than the design value embedded Level measurement