2017年08月29日

Reinforced hollow bar

Self drilling hollow bar support is an active form of support, the support has the advantages such as low cost, fast supporting speed, low labor intensity, especially greatly simplifies the mining working face end support and advanced support technology, provides security for the rapid development of coal mining face. It is an important supporting technology for coal mine development in recent years.

The problems existing in the tail of the self drilling hollow anchor rod is prominent in the period of application process,due to eccentric load, the tail of the strength is not enough, the extension rate is not enough, leading to the supporting effect of variation, for this problem, the high strength thick tail self drilling hollow bolt anchor tail through special processing, the tail of the grain refinement to improve the shape and intensity of the self drilling hollow anchor bolt’s tail, brittle increase caused by defects in the heat treatment process has changed before, not only improves the anchor tail strength, but also improve the elongation of self drilling hollow anchor bolt’s tail . Field applications have also proved that this technology has greater advantages.
Self drilling hollow bar’s designed tension is mainly depended by possibility, reliability and convenience of construction technique.

If tension designs too big, accordingly, the cross section and gravity are big, then it is difficult for inserting into hole and construction quality cannot be guaranteed, also it’s not easy to handle if tension test and validation test have problems; if tension designs too small, the amount of hollow anchor bolt should need many and the price costs high.

After confirming self drilling hollow bar’s tension, the design of cross section should depend on the design method of tensile bar, at the same time, the demand of construction should be readjusted if necessary.

The hollow anchor bolt’s head coupling should be designed basing on the principle design of prestressing force.

After confirmation of hollow anchor bolt, it’s necessary to calculate structures’ stability. If stability of structures can’t reach demand, the design of hollow anchor bolt should be reconsidered even if the design of every part of anchor bolt is reasonable and economic. Lengthening hollow anchor bolt, calculating again and consulting relevant calculation method to ensure stability of soil and rock, quality of projects.  

Posted by seo2@sinorockco.com at 18:55Comments(61)TrackBack(0)