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The Dewsbury rock netting project
was a Kirklees Metropolitan Council scheme to protect the safety
of pedestrians and motorists from the possibility of rock fall
on to the A638, Wakefield Road, near Dewsbury town center.
The area protected was a rock cutting of approximately 10
metres vertical height, above an existing 3 metre high retaining
wall. The rock slope above the retaining wall was secured
by Weldgrip PVC coated mesh and Gripforce
® Rockbolts. Two areas were netted, one approximately 100
metres and a 50 metre length, joining into an existing area
which had been netted previously.
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Loose vegetation was removed
from the slope, with care taken not to disturb any plant and
tree root systems. Galvanised and PVC coated welded steel mesh
with an aperture size of 75 x 75mm was used to secure the rock
slope. The rolls of mesh were laid from the top of the slope,
overlapping adjacent sections by 225mm. These were joined together
by stainless steel clips, using a compressed air clipping gun.
Weldgrip Turmag compressed air drilling machines and hollow
turbine scroll drill steels, with twin wing bits, were used
to drill the 32mm diameter rockbolt holes. An air flush method
of drilling was employed.
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<< A Turmag Drilling
Machine drilling holes for the rockbolts
Weldgrip 25mm diameter Gripforce
® Rockbolts were used to secure the netting. The 2.5m long bolts
were placed at 3 metre centres along the top and bottom of the
slope.
Shorter 1.5m long bolts were used as required, to secure the
mesh between the two rows. |
Mesh cut to fit around
the existing trees >>
The rockbolts were installed into two 800mm long polyester resin
slow set capsules. To ensure the resin was mixed correctly,
the rockbolts were spun through the capsules to the back of
the hole. |
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<< Mesh joints
being secured by stainless steel clips
A stainless steel rope was secured along the top and bottom
rows to tension the mesh. All the work carried out on the slope
was by rope access.
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Production bolts being
tested >>
On site pull test were done to test the bond strength
between the rock/resin interface. Tests were made on bolts installed
at the top of the slope to 40kN of load. |
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<< Mesh laid
from the top to the bottom of the cutting.
A scaffold was erected from the footpath to 1 metre above the
top of the existing wall, as a temporary safety fence whilst
work was carried out.
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Gripforce
® Rockbolts used to secure the mesh >>
The PVC coated mesh was secured by tightening the nuts onto
150mm diameter end plate assemblies. |
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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,
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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
