4 Advantages of Self-drilling Hollow Grouting Anchors compare with common Grouted Bolts

Sinorock Self-drilling Hollow Grouting Anchor is comprised of a hollow bar, a drill bit, a coupler, a centralizer, a plate and a nut. It is a new type of bolt which can perform drilling, grouting and anchoring in a single operation.
The Self-Drilling hollow bar is fully threaded, that can be cut to any length or extended according to the needs of the project. Grouting through the hollow bar can improve the grouting compactness, thereby improving the bond stress to the rock and also improving the durability of the bolt. Self-drilling Hollow Anchor is especially suitable for weak, broken and other difficult formations.
Common Grouted Bolt is an anchoring agent that uses cement mortar. This type of anchor rod is easy to install, low in cost, but weak in anchoring force. It is mostly used for slope protection with relatively complete rock structure or temporary anchoring. It is rare used underground but mostly used in tunnel construction. Grouted Bolt must be injected into the hole with mortar before inserting the bolts. The bonding force between the bolts and the surrounding rock is not as good as the Self-drilling Hollow Anchor and with less grouting choice of grout. It has a variety of reinforcement effects on the surrounding rock. Thus the reinforcement effect on the surrounding rock is also worse.
Now let’s see the compared working characteristics of the Self-drilling Hollow Grouting Anchor and the Common Grouted Bolt as follows:
1. Grouting quality and effective anchorage length
Common Grouted Bolts: The grouting fullness of Grouted Bolts is weak, and there are gaps and cavities between the rod body and the rock wall, which greatly weakens the effective anchorage length area.
Sinorock Self-drilling Hollow Grouting Anchor: It can effectively control the fullness of grouting and ensure the effective anchorage length area required by the design. If necessary, pressure grouting can be used to further strengthen the loose rock mass around the rod body.
2. Pallet force and prestress
Common Grouted Bolts: no supporting board force, no pre-stress.
Sinorock Self-drilling Hollow Grouting Anchors: It has support plate force, can prestress the rock mass, improve the shear strength of the weak structural surface and potential slip surface of the rock mass, and can form a compressive stress arch zone in the anchorage area of the rock mass under certain conditions.
3. Adaptability to weak rock formations
Common Grouted Bolts: It's often impossible to construct the rod in weak and broken geological conditions.
Sinorock Self-drilling Hollow Grouting Anchors: Combines drilling and grouting as a single operation. The rods can be performed in weak and broken geological conditions.
4. Durability
Common Grouted Bolts: The mortar around the rod body is not full, and because the rod body is not centered, the protection thickness is uneven, resulting in poor durability of the anchor rod.
Sinorock Self-drilling Hollow Grouting Anchors: The grouting is full between the rod body and the hole wall, and the position of the rod body is centered by the centralizer, and the thickness of the protective layer is sufficiently uniform. The hollow grouting anchor rod has good durability.
grouting effect
In summary, Sinorock Self-drilling Hollow Grouting Anchors have the characteristics of fast construction speed, large anchoring force, good anti-corrosion performance, simple operation, and timely provision of anchoring force. Although the unit price of Self-drilling Hollow Grouting Anchors is higher than that of Common Grouted Bolts, from the perspective of long-term hidden benefits, hollow grouting bolts can be fully anchored over the entire length of the bolt, especially with sufficient and uniform protective layer thickness around the rod body. Which greatly enhances the durability of the anchor rod. These implicit economic benefits are unmatched by Common Grouted Bolts.

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