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The Brokenberry Quarry sewage
treatment works scheme is a South West Water project to upgrade
and improve the water quality in the highly populated summer
holiday area of Torbay.
The quarry is situated to the south of the bay between Brixham
and Painton.
The project was managed as a partnership between Miller, Hyder
and South West Water. |
Rock Netting the quarry face was part of the first phase of
redeveloping the site.
The floor was excavated to level the ground, remove the infill
left after quarry operations finished, and expose the quarry face
ready for reinforcing.
The height of the walls varied between 5 to 15 metres. |
The whole quarry face was netted from top
to bottom using PVC coated mesh which was held in place by Weldgrip
Fibregrip ®
Rockbolts. The bolts were installed into small bore diameter
holes, which were drilled using Weldgrip Gopher drilling machines.
The pneumatic rotary drilling machines were secured in purpose
built frames mounted in telescopic hoists.
Weldgrip hexagon drill steels and 27mm twin winged bits completed
the drilling system to give nominally 28-29mm hole diameters
in the medium to hard sandstone. |
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Fibregrip ®
22m diameter 1.8 metre long polyester rockbolts were used to
secure the netting.
The bolts have tensile and shear strengths of 470kN and 129kN
respectively. |
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A breakout nut capable of withstanding
45Nm of
torque was used to install the bolts.
This enabled each bolt to be spun to the back of the hole through
resin capsules, using the Gopher drilling machine and a spinning
adapter.
Polyester slow set resin capsules were used to bond the rockbolts
into the strata. These have a cure time of approximately 5 minutes
after mixing. The rockbolt end assemblies consisted of a 150mm
diameter high load plastic end plate and a GRN (Glass Reinforced
Nylon) nut capable of withstanding 80kN of end load. |
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The end assemblies were tightened to the wire mesh after the
resin had cured. This allowed the torque setting to be overcome
and the nut to be run up the thread.
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Download the Printable PDF Brochure
If you would like to print the brochure for more information
on our drilling products please click on the download button.
You will need Adobe Acrobat Reader to view and print the brochure,
if you need to download a free version of Acrobat Reader please
click
here.
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3.5 meg |
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Download the Printable PDF Brochure
If you would like to print the brochure for more information
on our soil nails and rockbolts please click on the download
button.
You will need Adobe Acrobat Reader to view and print the brochure,
if you need to download a free version of Acrobat Reader please
click
here.
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4.2 meg |
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Bar
& 'AT' Rockbolts
