JGL Corporate brochure - Flipbook - Page 70
06.
Case studies, our projects
Challenges
Installing 1000m of microtunnelling under the
sea bed from a shaft at the cliff top.
The completion of this required the use of
compressed air interventions. The cover to
the sea bed was 5m above the soffit level of the
tunnel.
A pipe brake was used to combat the ground
water pressure pushing the pipes back when
the jacking pressure was released, ready to
complete an excavation cycle.
Ground conditions were chalk containing beds
of flints which were evident in the cliff face.
However, the roller cutters dealt with these
conditions well and there was the facility of
face access if any changes to the tooling were
required.
Added value
The 1800mm slurry machine and the pipe
brake were designed and manufactured by
Specialist Plant Associates.
The compressed air lock was designed and
manufactured by Specialist Plant. 90 ton
crawler cranes were provided by NRC. The
shaft sinking and microtunnelling were
completed by our tunnelling division.
Awards
Nominated by Costain for the Supply
ChainContractor of the Year.
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Joseph Gallagher Group | CORPORATE PORTFOLIO | 2026
