self drilling bolt

Seamless Steel Tube’s Quality Inspection Methods

As self drilling bolt’s raw material, seamless steel tube’s quality must be completely inspected according to product standard and technical specification. Specific inspection includes steel tube’s chemical component analysis, geometric dimension inspection, surface quality inspection, physical and chemical properties inspection, processing property inspection, metallographic analysis, thread inspection and measurement. The purpose is to ensure quality of steel tube and meet relevant standard code or technical condition requirement.


Reason Analysis of Tunnel Deformation

During tunnel construction, deformation often happens. Observing from tunnel surface, there are cracks, shedding phenomenon or underground water dropping appearing. If reason doesn’t get analyzed and maintained timely, worse deformation will happen.

self drilling anchor system

General Requirement of Self Drilling Anchor System’s Inclination

Self drilling anchor system’s inclination should be 15°~25° horizontal downward, no large than 45°. With increase of inclination, horizontal component of self drilling anchor system decreases. Too large inclination will reduce anchoring effect and increase vertical component on supporting structure, which will also cause settlement of retaining structure and surrounding foundation. To use self drilling anchor system’s pulling resistance effectively, self drilling anchor system should parallel with direction of side pressure effect.