Figure 7
Schematic diagram and site photograph of the track rockfall experiment: (a) three-dimensional sketch of the rockfall impact track test, (b) top view of the test, (c) photograph of the test site, and (d) diagram of the sensor track installation. (The impact position refers to the part of the track struck by the rockfall: 1) the center of a sleeper, 2) the rail away from the sensors, 3) the rail buried with the sensors, and 4) the edge of a sleeper near the sensors. The impact distance is the distance between the impact point and the first detector A along the rail. FBG sensors were installed at measuring points A, B, C, D, E and F, with intervals of 5 m, to record the vibration signal).
