Influence of Base Rock Deterioration on Tunnel Bottom Structure Damage under Train Excitation

Table 8

V surrounding rock fatigue damage calculation results of bottom structure in three characteristic stages.

State of surrounding rock	Structure part	Maximum damage value		Cumulative loading times (ten thousand times)		Fatigue lifetime (year)		Location of damage
		Heavy-haul railway	Conventional railway	Heavy-haul railway	Conventional railway	Heavy-haul railway	Conventional railway	Heavy-haul railway	Conventional railway
Phase I: denser	Track bed	1.315	1.123	1.13 × 10^4	1.33 × 10^4	76	89	Below the track
	Filling	1.112	0.944	1.36 × 10^4	1.59 × 10^4	90	106	Below the track
	Inverted arch	0.840	0.787	1.79 × 10^4	1.91 × 10^4	119	127	Area below the line
Phase II: local cavity	Track bed	1.493	1.250	1.01 × 10^4	1.20 × 10^4	67	80	Below the track
	Filling	1.333	1.099	1.13 × 10^4	1.37 × 10^4	75	91	Below the track
	Inverted arch	1.266	1.020	1.19 × 10^4	1.47 × 10^4	79	98	The area below the line
Phase III: cavity connection	Track bed	2.381	1.282	0.63 × 10^4	1.17 × 10^4	42	78	Below the track
	Filling	1.724	1.136	0.87 × 10^4	1.32 × 10^4	58	88	Below the track
	Inverted arch	1.961	1.111	0.77 × 10^4	1.35 × 10^4	51	90	The area below the line