The principle of vibration reduction of steel spring floating plate system The basic principle of steel spring floating plate track is to install a linear resonator (isolator) with low natural frequency between the track bed and the foundation to prevent the vibration transmitted from the rail. Into the foundation. The mass elements of the isolator are usually concrete slabs or concrete blocks, and the elastic damping elements are made of springs and dampers.
The rails of the steel spring floating slab track are indirectly fixed to a heavy and strong reinforced concrete cast bed board, and the track bed is floated on the steel spring isolator as shown. The ratio η of the excitation frequency fe generated during the subway running to the natural frequency f0 of the system is called the tuning ratio; the ratio VF of the amplitude of the fundamental force F2 to the amplitude of the exciting force F1 transmitted by the vibration during the subway running is called the transmission ratio. For the same excitation frequency, the lower the floating plate vibration isolation system f0, the better the vibration isolation effect. From the calculation formula of f0, it can be known that increasing the mass of the floating plate and reducing the stiffness of the lower spring can reduce the f0 of the system, thereby improving the vibration damping effect of the steel spring floating plate; however, the quality is often supported by space and structure. Strength limits, while the cost increases; reducing the stiffness of the elastic components is limited by system stability and safety.
Steel spring floating slab track 岔 construction technology Guangzhou Metro Line 3 laying steel spring floating slab roadway tunnel section tunnel structure is horseshoe shape, the section of the line is all straight, the whole line adopts short pillow buried integral track bed, for actual construction cross One of the faces. Tunnel backfill treatment The tunnel base is fully chiseled and cleaned manually. A <16mm×245mmYG2 type expansion anchor bolt is installed at the bottom of the tunnel side wall, and the backfill layer is firmly tied.
Set the center point of the isolator and drill and mark it with a <1mm electric drill. The diameter of the outer sleeve of the vibration isolator is the length of the side of the isolator, and the center of the vibration isolator is used as a reference to project the square ink wire frame and the center cross wire. Perform necessary repair or sanding on the surface of the backfill layer of each isolator to ensure that the elevation deviation is 0-5mm and the flatness deviation is ±2mm/m2. Install a special expansion anchor bolt at the center of the 30% vibration isolator ( The lateral limit system prevents the lateral displacement of the inner sleeve), and the outer sleeve of the auxiliary vibration isolator is positioned to prevent the outer sleeve of the vibration isolator from being displaced during the construction process.
To set up the ballast, firstly lay a 2mm thick polyethylene plastic film on the surface of the backfill layer and the side wall to isolate the track bed concrete and structural concrete. The film is slit at a position where the perforation is marked to expose the base mark. The self-made ballast special rail support frame is used to install the ballast, and the fasteners and the short sleepers are installed according to the design requirements. The geometrical dimensions of the ballast are adjusted with reference to the base mark. The elevation of the rail surface is reserved at 40 mm below the design rail surface elevation, and then the lateral support on the tunnel side wall is ensured to ensure the lateral stability of the entire stack.
Solved the major construction technical problems such as "perforation standard setting" and "drainage system construction" of steel spring floating plate track bed, accumulated rich construction experience, completed steel spring floating plate track bed with safety, high quality, high efficiency and economical rationality. The construction task of the turnout and the successful laying of the steel spring floating slab track turnout have filled the blank of domestic vibration reduction and vibration isolation technology. The application of this technology greatly reduces the vibration and noise interference when the train is running, and the vibration and noise reduction reaches 30dB.
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