Generally speaking, the self drilling anchor bolt is applicable for the stratum which suitable for retaining wall and soil nail wall, and it also suitable for the stratum which suitable for prestressed anchor bolt.
For the anchoring technology with drilling operation, drilling often becomes the most critical process, and directly affects the bearing capacity of the self drilling anchor. Drilling in loose soil and formation which affected by groundwater, hole collapse is a common phenomenon, which need to increase the difficulty and cost of construction by using casing pipe, casing pipe can improve the drilling speed, but have adverse effects on the bonding mortar and hole wall.
In loose strata and more pore, opening rock hole fracture, high pressure grouting can compensate for geotechnical defects, this condition requires adjusting slurry consistency to make mortar filling fracture for ensuring self drilling anchor bolt’s quality assurance.
Self drilling anchor is most suitable for the formation of pebbles and boulders, drilling is completed through grouting of surrounding rock disturbance part of effective reinforcement, expansion the diameter of self drilling bolt, If there is a small amount of water seepage in the drilling process, it can also be used to blow cement powder into the hole by using high pressure wind direction. Form temporary protective wall around drilling hole to reduce collapse.
The anchor bolt (including soil nailing) and prestressed anchor for on-site processing, its production method and process directly affect the quality.
The technological process is as follows: drilling and making self drilling anchor bolt, clear hole, install the self drilling anchor bolt, grouting and compensating grouting are applied, a prestress is fixed and an end is processed. The prestressed anchor cable by multi beam steel wire woven, prestressing requires specialized equipment, the construction quality is different, and
self drilling bolt products for factory production, reduce the production and two processes of installation of anchor bolt, prestressed simply tighten the bolts can improve the bearing capacity of 25%,reliable quality, improve work efficiency.