Discuss the factors influencing the quality of self drilling anchor bolt

The rode body of self drilling anchor bolt is made of round steel rebar or a threaded steel processed.

There are two inner factors affecting the quality of self drilling anchor bolt:

1)the material of self drilling anchor bolt rod and nut can not meet the standard demand or the precision and strength of self drilling anchor bolt tail and nut thread can not meet the standard requirements;

2) the welding joint and left-lateral self drilling anchor bolt rod body of the lap joint place destroyed the original toughness of the rod body, make the tension of rod body of self drilling anchor bolt damaged, when the roadway pressure high, it will caused roof accident by cut or pulled broken of self drilling anchor bolt rod body.Therefore, it can not burn out the self drilling anchor bolt body in the welding, at the same time, in addition to the material standard, the tail thread rolling process can be applied.

The external factors affecting the quality of self drilling anchor bolt:

The construction of self drilling anchor bolt mainly rely on manual operation to complete, not only the process, and the requirements are very strict, no matter which link problems will affect the quality of self drilling anchor bolt supporting.

1)The influence of the quality of self drilling anchor bolt rod eye

The eye depth of self drilling anchor bolt, angle, hole dust or water, aperture, etc are important factors affecting the quality of bolting.

2)The influence of self drilling anchor bolt installation

The rod body of self drilling anchor bolt generally use the sinistral twist round steel bolt or left-hand no longitudinal reinforcement high strength rebar，it should be stirred in a clockwise direction when stirring in the mount bolt holes,so the density of anchoring increasing, as with the anchoring force is bigger and bigger.Conversely,it will lead to the anchoring agent to extrapolate, reduces the anchoring at the same time, the anchor should have certain pre-tightening force, general pre-tightening torque should be above 14ON/m, so as to give full play to advantages of self drilling anchor bolt proactive and timely support.Therefore, when installing self drilling anchor bolts should be resin after solidification, tighten the nut in a timely manners as required.