Experimental Study on Stiffness Softening of Soil-Rock Mixture Backfill under Metro Train Cyclic Load

Table 2

Stiffness softening test program.

Specimen group	Rock content (%)	Compaction coefficient	Consolidation degree	Consolidation stress (kPa)	Cyclic stress ratio	Cycles	(Hz)
A1	20	0.97	0.98	100	0.12	15000	1
A2	20	0.97	0.90	100	0.12	15000	1
A3	20	0.97	0.80	100	0.12	15000	1
A4	20	0.97	0.98	200	0.12	15000	1
A5	20	0.97	0.90	200	0.12	15000	1
A6	20	0.97	0.80	200	0.12	15000	1
A7	20	0.97	0.98	400	0.12	15000	1
A8	20	0.97	0.90	400	0.12	15000	1
A9	20	0.97	0.80	400	0.12	15000	1
A10	10	0.97	0.98	200	0.12	15000	1
A11	40	0.97	0.98	200	0.12	15000	1