Self-Drilling Anchor Bolts

Self Drilling Anchor Bolts are a bolting solution for unstable ground conditions such as sand, gravel, silt, and clays, and in soft to medium fractured rock formations.

For projects facing such ground conditions, self-drilling anchors should be considered as the main productivity solution. Self-Drilling Anchors from Intech Anchoring Systems are designed for optimized installation, tailored to the project’s needs.

By drilling a hole in collapsing soil or loose rock, with a sacrificial drill bit and a hollow rod, and after the drilling operation injecting cementitious grout or resin into the hollow rod and surrounding cavity, self-drilling anchors are a top productivity solution.

Self drilling anchor bolts from Intech Anchoring Systems consists of:

Applications of Self-Drilling Anchors

Slope stabilization

Self-Drilling Anchors are used to stabilize unstable rock/soil formations. The unconsolidated or weathered ground conditions favor the SDA technique for a fast and simple method of installation compared to the traditional methods.

Foundations with micropiles

SDA micropiles can be defined as drilled piles, composed of injected grout with the anchor rod as steel reinforcement. They can be installed in sites with limited space using light drilling equipment, can be installed into most ground conditions including rock and are suitable for tension and compression loads. The big advantage is the combined drilling and grouting making high piling outputs possible.

Tunneling

Self drilling anchors are the most economical solution for the reinforcement of the tunnel circumference and advanced roof support for tunnel excavation in overburdened and soft fractured rock conditions.

Self-Drilling Anchor Equipment & Drill Bits

Sacrificial drill bits

The sacrificial drill bit is the most crucial part of the anchoring system and is responsible for the productivity of the installation. Intech Anchoring Systems offers a large range of drill bits to suit the changing geology encountered during projects. In order to improve on performance and cost efficiency, data is collected from projects around the world and incorporated into the design with the goal to improve penetration rate and bit quality and to reduce manufacturing and application costs.

The selection of drill bits

A successful installation of the SDA system depends on the selection of the most suitable drill bit. Compared to conventional drill bit types offered globally for maximum standing performance for rock or soil, the criteria for SDA drill bits are defined by consideration of the following factors:

SDA Anchor Components

Hollow anchor rods

The anchor rod features a hollow bore for flushing, or simultaneous drilling and grouting, and has a left-hand thread for connection to standard drill tooling. It is manufactured from API standard thick wall steel tubing, cold rolled to a standard ISO rope thread profile. The rolling process refines the crystaline structure of the steel, increasing the yield strength, and producing a durable drill rod suitable for a wide range of applications. The standard rope thread of the anchor rod produces an excellent bond between the rod and grout, as well as enabling connection to the drilling rigs and a wide range of drill steel accessories.

Extension couplings

The coupling features a patented design that enables direct end-to-end energy transmission between each bar, reducing losses and ensuring maximum percussive energy at the drill bit. To enable the correct seating of each bar within the coupler, all bars are chamfered with precision to enable the bar ends to have face-to-face contact.

Bearing plates

The bearing plates are forged steel plates with a center hole, allowing articulation of seven degrees in all directions. Intech Anchoring provides customized bearing plates for each application

Hexagonal nuts

The hexagonal nuts are manufactured from high precision steel with chamfered edges on both ends from high precision steel, and tempered to meet the stringent demands on anchor specifications and the daily operations of underground work. All nuts exceed the ultimate strength of the bar.

Galvanized anchors

Corrosion is a very complex process, and corrosion rates are very hard to predict accurately. However, analytical evaluations can be helpful to recommend the need for corrosion protected rock bolts. The full range of SDA bars and accessories is available with this corrosion protection.

Coupling adapters

Manufactured from thick-wall steel which is machined and case hardened, coupling adapters are used at high wear locations, typically just below the hammer drive. A locking torque is normally applied to the coupling box at the permanent joint to avoid release when additional anchor bars are added. All the coupling adapters are supplied with a bridge to act as a center stop. When a step-down (reducer) drive arrangement is used i.e. R38 shank to drive to install R32 anchor bar, a locking torque should be applied at the R38 end to prevent the R32 bar from climbing into the R38 chamber. Step-up drive arrangements are not recommended as the additional torque overloads the smaller drive.

Shanks

Rotary percussion is the preferred method of installation. Either a hydraulic or air hammer is suitable. To transfer the rotation and percussion from the hammer to the bar‘s system, there is a need for a shank adapter. Intech Anchoring Systems provides a full range of different shank adapters for different hammers and an inventory of shanks for the drills.

Grout coupling

After using standard flushing media (water or air), grouting must be done. For connecting the grouting hose from the pump with the anchor bar, the grout swivel is used. The grout swivel will be removed and reused after the grouting process is done

Why Intech Anchoring Systems?

In addition to materials and service, Intech Anchoring Systems will provide continual support through the entire project, including engineering/design, on-site support, load testing, installation expertise, competitive pricing, and rental equipment. Call us at 800-223-7015 for more information.