PURPOSE:To control the propagation of pressure wave in a pipe-like passage and to prevent the generation of impulsive wave specially in a remote place by arranging a large number of caves to the side of the pipe-like passage, and connecting between the pipe-like passage and the caves with connecting ways. CONSTITUTION:A large number of caves 2 are arranged to the side of a pipe- like passage 1 in the direction thereof to connect between each of the caves 2 and the pipe-like passage 1 with a connecting way 3 having a small section. At that time, the caves 2 are such that another auxiliary pipe line is partitioned to provide or that a plurality of pipe-like passages 1 and 1 can share one auxiliary pipe line. After that, in the case a train passes, the caves and the connecting ways 3 as a certain kind of resonance apparatus control level of pressure variations in the pipe-like passage 1 with the traveling in low. By connecting a large number of caves 2, a propagation speed of pressure wave in the pipe-like passage 1 is dependent on frequency, and pressure wave is dispersed to control the generation of impulsive wave.
展开▼
