It is crucial to prevent deformation of shield segment bolts during storage, as deformation may prevent them from being installed properly or affect their connection performance in shield tunnels. The following are some effective measures to prevent deformation:
Reasonable stacking methods
1. Vertical stacking
Shield segment bolts should be stacked vertically as much as possible. When stacked vertically, the deadweight of the bolts is mainly distributed along the axial direction, which can minimize the bending deformation caused by gravity. Arrange the bolts neatly and use special shelves or brackets so that each bolt has an independent storage position to avoid mutual squeezing and collision.
For longer bolts, support can be added in the middle to prevent sagging deformation caused by their own length. The support material can be made of wood or plastic to avoid damage to the bolt surface.
2. Layered stacking
If it is not possible to stack all vertically, pay attention to controlling the number of layers when stacking in layers. Place isolation pads between each layer, and the pads should be flat and have a certain strength. Generally speaking, the pads can be made of hard plastic plates or thin steel plates, and the thickness should not be too thin to evenly distribute the pressure of the upper bolts.
The number of bolts stacked on each layer should be reasonably planned and not too dense. There should be enough gaps between the bolts to prevent the bolts from being squeezed and deformed due to accidental collision or vibration during storage.
Environmental condition control
1. Temperature and humidity
The temperature and humidity of the storage environment need to be reasonably controlled. Too high temperature may cause the bolt material to expand and generate thermal stress, while too low temperature may make some materials brittle. Generally speaking, the storage temperature should be kept within the range of normal temperature (1535℃).
The effect of humidity on bolts should not be ignored. High humidity environment is prone to cause bolts to rust, and rust may further cause the surface of the bolts to be uneven and affect their shape. Therefore, humidity should be kept at a relatively low level, and the ideal relative humidity should be between 40% and 60%. Humidity can be controlled by installing dehumidification equipment, and the storage warehouse should be sealed well.
2. Prevent external impact
The location of the storage warehouse should be away from vibration sources and areas where heavy objects are frequently moved. If there are construction activities or traffic arteries near the storage environment, vibration and impact may be generated, which will be transmitted to the bolts and cause them to deform.
Inside the warehouse, the shelves and stacking areas should be reasonably laid out, and guardrails and buffer devices should be installed to prevent forklifts and other handling equipment from accidentally colliding with the bolt stacking area during operation, thereby protecting the bolts from deformation caused by external impact.
