A Study on Axial Compression Performance of Large Diameter-Thickness Ratio Concrete-Filled Gas Drainage Steel Pipe

Table 3

Degradation range and recovery range of axial bearing capacity of specimens.

No.	SSP-I-1	SSP-I-2	SSP-I-3	SSP-II-1	SSP-II-2	SSP-II-3	RSP-1	RSP-2	RSP-3
First peak stress (MPa)	36.44	37.94	34.05	36.17	35.03	37.85	43.01	42.79	40.45
Valley stress (MPa)	26.23	25.16	24.81	11.92	11.77	16.01	29.65	39.17	34.49
Rising peak stress (MPa)	35.67	36.15	33.06	22.65	20.93	22.49	42.44	43.14	40.13
Χ (%)	71.95	66.33	72.88	33.56	33.60	42.27	68.93	91.53	85.26
ψ (%)	97.87	95.30	97.10	62.61	59.75	59.40	98.67	100.8	99.13