Vibration Characteristics of Underground Structure and Surrounding Soil Underneath High Speed Railway Based on Field Vibration Tests

Table 2

Selection of attenuation index for different physical sources from the literature.

Physical sources	Type of source	Wave type	Attenuation index
Line source [3]	Line	Rayleigh	0
		Body	0.5
Point source [3]	Point	Rayleigh	0.5
		Body	1.0
Short length and high speed train [4]	Line	Body	1.5
Long length and slow speed train [4]	Line	Body	1.0