COTTER DAM

Foundation grout curtain and drainage under Australia's largest roller compacted concrete dam

Project Overview

Completed in 2013, the Enlarged Cotter Dam (ECD) comprises an 87m high roller compacted concrete dam (RCC) wall built downstream from
the old 26m high dam wall, along with two auxiliary dam walls along low-lying adjoining valleys. As of 2019 the ECD remains the highest
RCC dam constructed in Australia with a water storage of 78 gigalitres with a 482-hectare catchment. Geovert constructed the 60m deep
grout curtain under the full length of the 330m long ECD.

 

Using a contactor as diverse as Geovert allowed the restricted access drilling inside the steep galleries, foundation grouting, drainage works, depressurization drilling, rock bolting and over 2 years of rock scaling works to be completed using just one competent contractor without having to manage the interface of multiple subcontractors.

 

Geovert Solution

 

Hydraulic winches were installed at the top of each gallery incline to allow a 5t tracked drill rig and a skid mounted diamond coring rig to be hauled up the 42° stairs, gaining 80m elevation over the length
of the incline. The foundation grouting was undertaken in this confined gallery to allow the RCC construction to continue above. A fully automated grout injection control system was installed in the
gallery, ensuring the GIN stop criteria were met, providing real time construction monitoring using the Jean-Lutz instrumentation.

 

Upon completion of the grout curtain foundation which required primary, secondary, tertiary and quaternary grouting, drainage holes were drilled beneath the dam monolith. Pressure relief drains were drilled from the crest of the dam, requiring extremely low deviation drilling to intersect the breakthrough target area, 1.5m wide, on the gallery roof, up to 65m below (2% deviation).

Ground Engineering Capabilities

Ground Engineering Market Sectors

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Australia Headquarters

Block B, Level 1, 

Suite 8 / 247 King St,

Mascot, NSW 2020, 

Australia

+61 (2) 9700 7975

New Zealand Headquarters

15 Kaimahi Rd
Wairau Valley
North Shore 0627

+64 9 837 7808

United States Headquarters

1919 W Elk Pl
Denver, CO 80211
United States

+1 720 452 1191

Singapore Headquarters

80 Robinson Road, #02-00
Singapore 068898

+65 9640 2997

Asset Integrity Maintenance 

Capabilities:

Blasting and Painting

Bridge Maintenance

Certified Fall Arrest Anchor Systems

Concrete Condition Inspections

Concrete Repair and Crack Injections

Condition Surveys

Confined Space

Corrosion Management

Fabrication and Welding

Industrial Cleaning and Water Blasting

Non-Destructive Testing (NDT)

Plant Shutdowns

Protective Coatings and Waterproofing

Refractory Maintenance

Rope Access

Rigging and Heavy Lifting

Seismic and Structural Strengthening

Temporary Access Platforms

Avalanche Protection

Capabilities:

Avalanche barriers and fences

Avalanche towers

Remote avalanche control systems

Snow avalanche protection systems

Snow netting

Basements & Foundations

Capabilities:

Capping Beams

Ground Anchors

Limited Access Drilling

Micro Piling

Mini Piling

Rock Bolting

Seismic Retrofit

Self Drilled Hollow Bar

Shotcrete

Soil Nails

Temporary Ground Anchors

Timber Pole Walls

Geohazard Mitigation

Capabilities:

Active Mesh Stabilisation

Debris Flow Barriers

Design and Build

Devegetation

Drill and Blast

Erosion Control

Geotechnical Inspection & Instrumentation

Rockfall Assessments and Investigation

Rockfall Attenuators

Rockfall Barriers

Rockfall Mesh Drapes

Rockfall Modelling

Scaling and Block Removal

Shallow Landslide Barriers

Ground Anchors

Capabilities:

Ground Anchor Inspection

Ground Anchor Lift Off Test

Permanent Multistrand Ground Anchors

Platipus Anchors

Post Grouted Ground Anchors

Pregrouted Ground Anchors DCP

Removable Ground Anchors

Restressable Ground Anchors

Self Drilled Hollow Bar Anchors

Temporary Multistrand Ground Anchors

Ground Support

Capabilities:

Active Mesh Stabilisation

Bulk Infil Grouting

Cable Bolts

Drill and Blast

Geotechnical Inspection & Instrumentation

Rockfall Assessments and Investigation

Highwall Stabilisation

Longwall Stabilisation

Portal Protection

Rock Bolting

Rockfall Barriers

Rockfall Mesh Drapes

Rockfall Modelling

Scaling and Block Removal

Retaining Structures

Capabilities:

Active Mesh Stabilisation

Design and Build

Drill and Blast

Geotechnical Inspection & Instrumentation

Rock Bolting

Rock Bolting

Rockfall Attenuators

Rockfall Barriers

Rockfall Mesh Drapes

Rockfall Modelling

Scaling and Block Removal

Rockfall Protection

Capabilities:

Active Mesh Stabilisation

Design and Build

Drill and Blast

Geotechnical Inspection & Instrumentation

Rock Bolting

Rock Bolting

Rockfall Attenuators

Rockfall Barriers

Rockfall Mesh Drapes

Rockfall Modelling

Scaling and Block Removal

Rope Access

Capabilities:

Emergency Response

Geotechnical Instrumentation

Supervised Inspections

Slope Stabilisation

Capabilities:

 

Active Mesh Stabilisation

Devegetation

Erosion Control

Ground Support

Retaining Walls

Rock Bolting

Scaling and Block Removal

Shotcrete

Soil Nails

Tunnelling

Capabilities:

 

Canopy Tubes

Ground Anchors

Injection Grouting

Portal Protection

Rock Bolting

Shotcrete

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