Track spike anchorage strength and control of rail lateral displacement
Q1: What are the core evaluation indexes of spike anchoring strength?
A1: The core evaluation indexes of spike anchoring strength are pull-out resistance and shear strength. Pull-out resistance reflects the ability of spikes to resist vertical rail displacement, and shear strength measures the performance of spikes to resist transverse force. The combination of the two can comprehensively evaluate the anchoring quality of spikes, which is a key basis for judging the stability of sleeper fixation.
Q2: Why will insufficient spike anchoring strength lead to transverse rail displacement?
A2: Insufficient anchoring strength will reduce the bonding force between spikes and sleeper sleeves and fail to effectively transmit wheel-rail transverse force; when the wheel-rail transverse force is large in curve sections, spikes will loosen and fracture due to excessive shear force, and the rail loses transverse constraint, resulting in transverse displacement, gauge widening and track direction deviation.
Q3: What key impacts do anchoring agent types have on spike anchoring strength?
A3: General-purpose anchoring agents are suitable for ordinary-speed lines and can meet the basic anchoring strength requirements; high-strength anchoring agents are suitable for high-speed and heavy-haul lines, which can greatly improve the bonding strength between spikes and sleeves and resist shear force under large loads; low-temperature anchoring agents are suitable for cold environments to ensure that the anchoring strength does not decay at low temperatures.
Q4: What damage will transverse rail displacement cause to fastening accessories such as pressing plates and elastic bars?
A4: Transverse rail displacement will change the fitting state of pressing plates and rails, leading to uneven stress and accelerated wear and deformation of pressing plates; elastic bars will bear additional transverse load due to rail deviation, accelerating elastic attenuation and fatigue crack generation; under-rail pads will also deviate, resulting in reduced vibration reduction performance, and the stability of the overall fastening system is damaged.
Q5: How to strengthen spike anchoring and displacement prevention and control from construction and operation and maintenance?
A5: Thoroughly clean sleeper sleeves before construction, stir anchoring agents according to standard proportion to ensure the spike insertion depth and full filling of anchoring agents; regularly detect spike anchoring strength in operation and maintenance, and re-anchoring or replace loose and failed spikes; increase detection frequency in curve sections and adjust the transverse position of rails in time to prevent displacement.