Impact of Damaged Sleeper Embedded Sleeves on the Fastening System
Q1: What are the common damage forms of embedded sleeves?
A1: Mainly including internal thread slipping, sleeve cracking, anchorage loosening, upper orifice reaming, inclined deformation, etc. Among them, thread slipping and anchorage loosening are the most common, which directly lead to the failure of bolt fastening and fasteners.
Q2: Why does sleeve damage cause uneven clip stress?
A2: Loose or inclined sleeves deflect bolt installation and clip support points, resulting in uneven clamping force distribution. Some clips are overloaded and fatigued, while others are insufficiently pressured and loose, disordering the overall stress state of the line and accelerating the failure of the fastener system.
Q3: What impact does vibration have on the service life of embedded sleeves?
A3: Long-term train vibration causes fretting at the sleeve-concrete interface, gradually reducing bonding strength. Vibration also aggravates thread wear, rapidly damaging the internal teeth of sleeves. Therefore, sleeve damage is more concentrated in joints and curved sections with strong vibration.
Q4: Why is it difficult to simply repair after sleeve failure?
A4: Sleeve damage is often accompanied by internal anchorage failure, and simple re-tapping or filling cannot restore sufficient strength. Under the action of train dynamic load, the repaired part is extremely easy to loosen again with low reliability, usually requiring rebar planting or sleeve replacement.
Q5: How to extend the service life of embedded sleeves and reduce diseases?
A5: Select high-strength and high-bonding sleeves to ensure construction anchorage quality. Avoid forcible knocking when installing bolts to prevent damage to internal threads. Regularly check the sleeve status and rectify in time if loosening or slipping is found. Maintain stable bolt torque to reduce interface fretting wear.