AT - Power Set Self-drilling Tube Spiles 

In Tunneling, spiles are generally used for local reinforcement ahead of the tunnel face. As an alternative to conventional spile systems such as rebar spiles, ram spiles, or IBO - spiles, ALWAG offers the recently own-developed AT - Power Set Self-Drilling Tube Spiles. This reinforcement element is installed self-drilling in terms of a one-step operation, being suitable for safe and time-optimized excavation in loose rock or soil. 

System description 

The installation of the AT - Power Set Self-drilling Tube Spile is accomplished simultaneously while drilling the spile bore hole. Thereby, the ground is treated with care, and the time-consuming pre-drilling and following spile installation is reduced to one operational step.

Compared to self-drilling installed spiles in terms of IBO - Self-drilling anchors, the AT - Power Set Self-Drilling Tube Spile is made of a thin-walled steel tube. It is worth mentioning that this steel tube has a higher moment of inertia as comparable IBO - spiles. 

System components

The AT - Power Set Self-drilling Tube Spile is available in standard lengths from 3,0 to 4,5 m and consists of the following system components:

• AT - Power Set Self-drilling Tube Spile Ø 51 x 3,2 mm
• Single-use drill bit Ø 52 mm with HEX 28 connection
• Power Set Drill Steel HEX 28 / T38
• Adapter T38 with integrated impact ring

Grouting or an injection of the AT - Power Set Self-drilling Tube Spile is not necessary, but optionally possible. Therefore, the spile tube can be delivered with customized perforation holes at the far end. 

Installation 

AT - Power Set Self-drilling Tube Spiles are installed using standard drilling equipment. Prior to the installation, the spile tube and the single-use drill bit are put onto the hexagonal drill steel. This Power Set Drill Steel is connected to the shank adapter via a coupling adapter. The impact ring of the coupling adapter transfers the impact energy of the hydraulic hammer carefully on the spile tube.

The tube spile is installed simultaneously while drilling the borehole. After installation is accomplished, the single-use drill bit remains at the toe of the borehole and the drill steel is pulled back. 

Main advantages of AT - Power Set Self-Drilling Tube Spiles 

• One-step installation procedure
• Safe and fast installation using standard drilling equipment
• Optimization of the excavation geometry and increased advance per round
• Easy adjustment to changing ground conditions
• Careful ground treatment due to self-drilling installation
• Minimization of overexcavation and additional convergence
• Immediate reinforcement after the spile installation is accomplished
• Unproblematic installation in case of unstable boreholes
• Optionally available with perforation holes for drainage or injection purposes
• Higher moment of inertia against bending as comparable rebar spiles, ram spiles or IBO - spiles