Study on Pretightening Loss Effect of Bolt Support in Deep Soft Rock Roadway

Table 4

Test results of the ribbed steel wire anchor rod.

Tightening torque (Nm)	Bolt preload (kN)
	1	2	3	4	5	6	7
100	23.40	29.20	23.40	22.90	23.90	20.00	27.30
125	28.80	33.20	30.20	27.30	29.70	24.90	32.20
150	31.70	38.00	35.10	31.70	34.10	27.80	40.00
175	32.20	44.90	40.00	32.20	36.60	32.20	43.90
200	41.50	51.20	45.40	39.50	43.40	41.50	48.80
225	46.30	56.10	50.20	46.30	44.40	44.90	53.20
250	46.30	61.00	51.20	52.70	51.20	49.30	55.60
275	51.70	65.40	54.10	51.20	57.10	53.20	58.10
300	61.00	70.80	57.60	51.60	63.90	58.10	60.50
325	64.40	78.10	61.00	63.90	67.60	64.40	62.90
350	72.70	79.50	65.90	70.80	69.30	68.80	65.90