Anchoring Technology and Track Compatibility of Rail Spikes
What are the core construction ratio and process of sulfur anchoring?
The material ratio of sulfur anchoring is sulfur: cement: sand = 1:1:3, which can ensure the strength and fluidity of the anchoring agent and balance the anchoring effect and cost. Before construction, the anchoring hole of the sleeper must be cleaned to remove debris and floating dust in the hole to avoid affecting the bonding force between the anchoring agent and the hole wall. Then heat the proportioned materials to 160-180℃ to melt them into a uniform paste to ensure no particle agglomeration. During pouring, it should be slowly injected from one side of the hole to discharge the air in the hole and prevent cavity defects. After pouring, it needs to be left to cool for 20-30 minutes. After the anchoring agent is completely solidified, install the fastener components to ensure the overall stability of the anchoring.
What are the advantages of resin anchoring compared with sulfur anchoring?
Resin anchoring does not require high-temperature heating and can be cured at room temperature, eliminating the open fire construction hidden danger of sulfur anchoring and improving construction safety. The bonding strength of its anchoring agent is higher, and the anchoring force can reach more than 65kN, about 5kN higher than that of sulfur anchoring, which is suitable for the high load requirements of high-speed and heavy-haul lines. The curing time of resin anchoring is only 30 minutes, much faster than the cooling time of sulfur anchoring, which greatly shortens the construction period and improves the line laying efficiency. The anchoring agent is an environmentally friendly material with no toxic gas emissions, meeting the environmental protection requirements of modern engineering. At the same time, the resin anchoring agent has excellent aging resistance, and the anchoring performance decays slowly in humid environments, extending the service life of the spike.
What are the applicable scenarios and structural characteristics of mechanical anchoring?
Mechanical anchoring is suitable for line sections that require frequent disassembly and adjustment such as turnouts. It is fixed through the threaded connection between the spike and the pre-embedded sleeve, facilitating later maintenance and replacement. Its structural core is the metal sleeve pre-embedded in the sleeper, and the thread on the inner wall of the sleeve needs to be anti-corrosion treated to prevent rust from affecting the disassembly and assembly performance. The thread accuracy of the spike must be strictly controlled, and the matching gap with the sleeve must be less than 0.1mm to ensure the tightness of the connection. The anchoring force of mechanical anchoring can reach more than 55kN, which is slightly lower than that of resin anchoring, but it is sufficient to meet the load requirements of the turnout area. In addition, its construction does not require waiting for curing, and it can be put into use immediately after installation, adapting to special working conditions such as emergency repair.
What special treatments are required for spike anchoring in alpine regions?
In alpine regions, low-temperature resistant anchoring agents should be selected. Antifreeze should be added to sulfur anchoring, and low-temperature curing products should be selected for resin anchoring to avoid brittle fracture of the anchoring agent at low temperatures. The anchoring hole needs to be insulated in advance to prevent frost on the hole wall from affecting the bonding of the anchoring agent. If necessary, the hole wall can be preheated to 5-10℃. The material of the spike should be low-temperature resistant alloy, and its low-temperature impact toughness should reach ≥27J to prevent brittle fracture of the spike at low temperatures. After anchoring, thermal insulation materials should be wrapped around the spike to slow down the impact of sudden temperature changes on the anchoring structure. In addition, the frequency of pull-out sampling inspection after anchoring should be increased to ensure that the anchoring force can still meet the standard in low-temperature environments.
How to detect whether the spike anchoring quality meets the standard?
A spike pull-out tester can be used for the pull-out test. The anchoring force of spikes for ordinary lines should be ≥60kN, and that for high-speed lines should be ≥70kN. If there is no obvious displacement or pull-out, it is judged as qualified. Check the perpendicularity between the spike and the sleeper through visual inspection, and the inclination deviation should be ≤2° to prevent uneven stress on the spike and loosening. Observe the surface state of the anchoring agent, with no defects such as cracking and falling off, and no gaps in the bonding with the hole wall to ensure overall integrity. Record the curing time of the anchoring agent to ensure that it meets the process requirements and avoid insufficient curing affecting the anchoring strength. In addition, the anchoring force can be retested after rain or freeze-thaw cycles to verify its performance stability in harsh environments.