Self-drilling hollow anchor bar VS ordinary mortar bolts

Geotechnical anchoring is an important branch of geotechnical engineering. With the vigorous construction of infrastructure in recent years, it has been widely applied in the Hydraulic engineering, highway construction ,ground and foundation projects, etc.

For a long time, ordinary mortar anchor has been widely used in the field of tunnels and slopes because of its low cost. However, with the development of geotechnical anchoring technology, self-drilling hollow anchor bolts are gradually replacing ordinary mortar anchors in the field of geotechnical anchoring due to the advantages. So what are the advantages of self-drilling rock bolt? Analysis are from three aspects:

With the continuous development of hollow grouting technology, the demand for hollow anchors is also increasing. This has prompted the processing of hollow bolts and accessories into equipment production, which has greatly reduced production costs. Compared with mortar anchors, self-drilling hollow anchors have greater anchoring force. So the cost can be further reduced by reducing the density of anchor bolts.

Ordinary mortar anchors often use the process of grouting first and then inserting steel bar. This process is difficult to ensure the fullness of the grouting and the steel bar will be exposed. Then it will cause corrosion if the bare steel bar contacts with groundwater, thus reducing the durability of the mortar anchor. Self-drilling hollow grouting bolts combine drilling and grouting together, cement slurry will enter through the hollow pipe. When the slurry flows from the bottom to the orifice, the hole collar plug and the domed plate prevent the slurry from overflowing, to ensure the grouting is full. This allows a sufficiently thick and uniform protective layer to be formed around the hollow bar, which greatly improves the durability.

3.Geological environment adaptability
Ordinary mortar anchors often use the process of grouting first and then inserting steel bar, which makes human factors a great influence on grouting effect. Especially for anchors longer than 3.0 meters, the fullness of the grout is more difficult to control. The effective anchor length is often far from the design requirements, so there are serious hidden dangers in the engineering. Self drilling anchor bolts provides higher bonding stress than smooth steel pipe depending on continuous wave thread. It also has the characteristics of arbitrary cutting or using couplers for lengthening. It fundamentally reversed the situation that anchor bars could not be placed or the length could not meet the requirements in the soft and narrow formations.

Sinorock® has been focusing on the research of self-drilling hollow anchor bolts for many years, and has developed four product systems for different geology, namely: R thread self-drilling anchor bolt system, T thread self-drilling anchor bolt system, Double anti-corrosion anchor bolt system, Stainless steel anchor bolt system. Engineers can provide professional system solutions according to the geological conditions, making the construction of the project safer and more efficient.

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