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

Table 3

Pretightening force coefficients of different diameters.

Bolt diameter (mm)	Theoretical coefficients ()	The coefficient after loss ()	The proportion of loss
16	0.23∼0.71	0.14∼0.37	0.39∼0.48
18	0.21∼0.64	0.12∼0.34	0.43∼0.47
20	0.19∼0.57	0.11∼0.31	0.42∼0.45
22	0.17∼0.52	0.10∼0.28	0.41∼0.46