The Hydrabolt is a fabricated steel tube, "C" shaped
in cross section, and sealed at both ends. At one end a hydraulic
nipple, with integral non-return valve, allows connection to a hydraulic
pump.
After drilling a support hole in the rock to
the required diameter and length, the Hydrabolt is inserted and a
pump is used to expand the tubular rockbolt radially with water at
pressures typically 25MPa (3500psi). Frictional resistance between
the wall of the hole and Hydrabolt provides outstanding pull-out
resistance.
The Hydrabolt has been designed to facilitate ease of installation
and to provide the user with immediate support and a safe working
environment. Unlike other designs, the Hydrabolt incorporates a check
valve to prevent the fluid from being released once the inflating
nozzle is removed. This system provides a 300% better grip as the
clamping inside the hole adapts to the shape, size and irregularities
of the hole and distributes the clamping force evenly throughout
the length of the hole. As the installed Hydrabolt is sealed the
internal corrosion is self-inhibiting.
The patented design of the Hydrabolt valve provides
a visual method of verifying the correct installation of the roofbolts.
The integral load indicator indicates that the Hydrabolt has been
correctly installed by popping forward once the Hydrabolt has been
installed with the correct internal pressure; secondly the colour
of the load indicator identifies which length of Hydrabolt has been
installed. The load indicator also confirms whether a Hydrabolt or X-Pandabolt has
been installed.
Advantages of Hydrabolts
Quick and easy to install
Wide expansion range
Patented non-return valve which limits "spring-back" giving
increased pull-out resistance
Pressurising done remotely
Not affected by blasting vibrations
No resin or grout required
No parts to lose in transport
Not susceptible to rock strength
Load distributed evenly over entire length
of hole
Provides immediate support
Range
Three models of the Hydrabolt are currently
available and can be manufactured in lengths ranging from 0.9 to
3.0 meters in increments of 0.3 meters. Non-standard lengths
can be accommodated upon request.