The three most popular methods for installing rock bolts are grout or resin anchoring, mechanical anchoring, and anchoring. Depending on the site’s geology and structural needs, each approach has unique benefits.
Mechanical anchoring
In applications involving rock reinforcement, mechanical anchoring, also referred to as point anchoring, is a popular installation technique that offers instant support. Usually, mechanical anchor bolts with an expansion shell attached to one end are used in this procedure.
The bolt is placed when a hole is drilled into the rock during installation. To establish a strong mechanical lock, torque is then used to expand the shell and press it firmly against the borehole walls. The technology is particularly helpful when speed and early assistance are crucial, like during tunnelling operations or temporary excavation support, because it provides instant load-bearing capacity.
Hard, competent rock is ideal for mechanical anchoring. The expansion shell might not provide a solid grip on softer or more broken ground, and long-term stability might be jeopardised, especially in settings where dynamic loads or vibration are present.
Resin and grout anchoring
For exceptional long-term performance in difficult ground conditions, resin and grout anchoring techniques are frequently utilised to build a solid, full-length link between the bolt and the surrounding rock. Usually used in conjunction with these anchoring techniques, rebar bolts are ideal for fully bonded applications because of their ribbed surface and bonding agent compatibility.
Resin anchoring involves inserting pre-packaged resin capsules into the drill hole. The capsules shatter and combine when the rebar bolt is inserted and rotated, enabling the resin to flow around the bolt and solidify forming a load-transferring connection.
The idea of grout anchoring is similar, but cement-based grout is used. Grout can be injected into the borehole either before or after the bolt is inserted, depending on the technique. The grout firmly anchors the bolt by creating a continuous bond along its length once it has cured.
Resin and grout systems offer greater corrosion resistance, high load capacity, and dependable performance, particularly in weak, fractured, or weathered rock masses, despite requiring more careful installation and longer curing times than mechanical anchors.
One-step drilling and grouting anchoring
An effective anchoring method that integrates grout injection and anchor installation into a single, continuous process is simultaneous drilling and grouting. In situations where the ground is unstable or falling, where it is essential to stabilise the borehole right away after drilling, this technique works very well.
Hollow threaded bars are frequently utilised in this method as the anchor and drill rod. The annulus between the anchor and the surrounding earth is filled while drilling continues by pumping cementitious grout through the bar’s hollow core. As drilling progresses, this real-time grouting procedure guarantees complete encapsulation of the anchor in addition to flushing away loose material.
The grout solidifies after installation, forming a strong, corrosion-resistant bond that runs the length of the bar. Even in rock formations that are cracked or contain water, this offers dependable weight transfer and long-term ground support.
This technique has several benefits, including shorter installation times, better bond quality, and a lower chance of borehole collapse, even though it calls for specialised tools and a regulated pumping rate. In tunnelling, slope stabilisation, and foundation reinforcement projects where ground conditions are difficult and reliable anchorage is essential, simultaneous drilling and grouting is a tried-and-true method.
