Failure criteria for Wood Railway Sleepers
The failure criteria for Wood Railway Sleepers are as follows:
(1) the decayed nail hole loses the pressure bearing capacity, and there is no place to change the hole due to decayed nail hole, and the nail cannot be held.
(2) the broken or spliced joint part is separated, and the gauge cannot be maintained.
(3) for mechanical wear, the thickness of lines with allowable speed greater than 120 km / h is less than 140 mm after flattening or removing rotten wood, and the thickness of other lines is less than 100 mm.
(4) it is not allowed to bear pressure or hold nails due to splitting or other damage.
Wood Railway Sleepers protection measures
The main reasons for the failure of hardwood timber sleepers
are corrosion, mechanical wear and cracks. Cracks and mechanical wear will accelerate the decay of Wood Railway Sleepers, and decay will also aggravate the mechanical wear and crack expansion. Therefore, in the measures of prolonging the service life of Wood Railway Sleepers, comprehensive consideration should be given.
Anti corrosion treatment is the main measure to extend the service life of Wood Railway Sleepers. Wood Railway Sleepers without anti-corrosion treatment are called plain sleepers and oil sleepers after anti-corrosion treatment. Commonly used preservatives such as water-soluble sodium silicate are made into antiseptic sleepers. Other measures include: reducing the mechanical wear, such as expanding the area of the base plate, reducing the unit pressure on the surface of the wooden sleeper, etc.; pre drilling the nail holes on the wooden sleeper; the connection between the base plate and the wooden sleeper should have separate parts to minimize the vibration of the base plate. The space between the base plate and the wooden sleeper shall be provided with anti-corrosion treated base plate or pressed asphalt Hessian to prevent the invasion of dirt, water or sand. In order to prevent cracks in Wood Railway Sleepers, the moisture content before anti-corrosion treatment shall be strictly controlled. For the cracks that have been formed, the anti-corrosion slurry can be poured in and clamped first, and then bound with iron wire to avoid aggravating the cracks after laying.
When laying Wood Railway Sleepers, the sleepers with the same size, strength and durability shall be laid together in sections. The joints shall be of standard size and good material. It should be noted that the center of the tree is facing down, if there are fillets, the large side is facing down.