Ges of your velocity in the roadbed bottom for the subsoil bottom (i.e., V6 to V11) reach 86.7 . In contrast, the amplitude and intensity with the velocity are improved for the case of v = 270 km/h. The vibration velocity amplitudes at V5, V6, V7, and V11 are four.2, 2.55, 1.58, and 0.45 mm/s, that are 7, 4.four, three.3, and five.six occasions extra than those at the corresponding position of v = 90 km/h. The attenuation ratio in the velocity in the roadbed bottom V5 to the subsoil V11 is 82.four . The vibration velocity propagates down along the embankment and attenuates steadily. Vibration isolation and attenuation phenomena occur within the embankment and pile aft foundation. The vibration waves move along the subsoil, and reduce to a very low level in the subsoil, which is substantially decrease than that at the roadbed surface. The frequency contents of your vibration velocities at the road, raft, and subsoil are shown in Figure ten. For v = 90 km/h, the peak values appear at a frequency point below ten Hz, including 1, three, and 9 Hz, reflecting the characteristic frequencies in the geometry in the train compartment. The peak values on the vibration velocity frequency spectrum are distributed in low-frequency and medium-frequency regions, respectively. In Figure 10a, there’s a little amplitude of vibration power within the 27 40 Hz area of the roadbed, plus the vibration wave is enhanced in this frequency band, indicating that the characteristic frequency on the vibration of the roadbed packing is distributed within this area. In Figure 10b, for v = 270 km/h, facts on the frequency contents shows peaks at about 3, 9, and 27 Hz. Compared using the low speed, the peak points in the vibration speed spectrum steadily move towards the medium-frequency location, and increase with the enhance of the train speed. PF-07321332 supplier Bigger velocity spectrum peaks occur within the selection of 27 40 Hz, which is eight times extra than that at low speed, as well as the ratio of vibration energy is higher than that at low speed.Appl. Sci. 2021, 11,Appl. Sci. 2021, 11, x FOR PEER REVIEW13 of12 of0.Vibration velocity(mm/s)0.four 0.2 0.0 -0.2 -0.four -0.six -0.8 0.0 0.5 1.0 1.five two.0 2.five three.0 3.five 4.0 four.5 five.Time(s)Vibration velocity(mm/s)0.V=90km/hRoad bed (V5)5 Road bed (V5) V=270km/h 4 3 two 1 0 -1 -2 -3 -4 -5 0.0 0.5 1.0 1.five 2.0 two.five three.0 three.5 four.0 four.five five.Time (s)(a)0.(b)Raft(V6)V=90km/hVibration velocity(mm/s)Vibration velcity(mm)0.6 0.4 0.two 0.0 -0.two -0.4 -0.six -0.eight 0.0 0.5 1.0 1.five two.0 2.5 3.0 three.5 4.0 4.five 5.3 two 1 0 -1 -2 -V=270km/hRaft (V6)-4 0.0 0.5 1.0 1.5 2.0 two.5 three.0 three.five 4.0 four.five 5.Time (s)Time (s)(c)0.five Ceftiofur (hydrochloride) Autophagy Cushion (V7) V=90km/h 0.four 0.three 0.two 0.1 0.0 -0.1 -0.2 -0.3 -0.four -0.five 0.0 0.5 1.0 1.five 2.0 two.5 three.0 three.five 4.0 4.five five.(d)2.0 1.five 1.0 0.five 0.0 -0.5 -1.0 -1.5 -2.V=270km/hCushion (V7)Vibration velocity(mm/s)Vibration velocity(mm/s)0.0 0.5 1.0 1.five two.0 two.5 3.0 three.5 four.0 4.five five.Time(s)Time (s)(e)0.10 Bottom of subsoil (V11) V=90km/h 0.08 0.06 0.04 0.02 0.00 -0.02 -0.04 -0.06 -0.08 -0.10 -0.12 0.0 0.5 1.0 1.five two.0 two.five three.0 three.5 four.0 4.five 5.0 0.V=270km/h(f)Bottom of subsoil(V11)Vibration velocity(mm/s)Vibration velocity(mm/s)0.six 0.four 0.two 0.0 -0.two -0.4 -0.-0.eight 0.0 0.5 1.0 1.five two.0 two.5 three.0 three.five 4.0 four.five five.Time (s)Time (s)(g)(h)Figure 9. Time history curves of vibration velocities at various areas from the pile aft foundation. (a) Roadbed (V5, v = 90 km/h), (b) Roadbed (V5, v = 270 km/h), (c) Raft (V6, v = 90 km/h), (d) Raft (V6, v = 270 km/h), (e) Cushion (V7, v = 90 km/h), (f) Cushion (V7, v = 270km/h), (g) Bottom of subsoil (V11, v = 90 km/h), (h) Bottom of subsoil.