Basin & Wall construction

OBJECTIVES

Two basins/ponds were needed to:

• capture rainwater from the surrounding land
• remove silt
• recycle water for use in the quarry for dust control and concrete manufacture.

KEY CHALLENGES

Loose, unstable soil.

• The client wanted to use leftover concrete blocks from the quarry and batch plant. Old truck tyres were also available.

CONSTRUCTION STEPS 

Construction steps for base/floor included:

1. Create a reinforced platform at the base of the pond using TS204.
2. Installation of the waterproofing layer using Bentoliner BL100 GCL.
3. Placement of cushion geotextile to protect the GCL from the gravel base.
4. Placement of 300-500mm gravel base and compaction.

Construction steps for the embankment included:

1. Trim batter and create anchor trench.
2. Installation of the Bentoliner BL100 GCL down the batter and in the anchor trench.
3. Placements of the TS202 woven as a weather protection to the Bentoliner GCL and to act as slip plane from the backfill.

Construction steps for the reinforced block wall:

1. Design alternative acceptance by consultants was to use the TS600/50 geogrid as the primary reinforcement at 1m centres to suit the concrete block. This grid would sit in between the blocks relying on their weight plus nailing and anchored back 7.5-8.0m.
2. The SG500 would provide secondary reinforcement as a wraparound behind the concrete blocks at 450-500mm centres. The design assumed there was no resistance provided by the concrete blocks that weighed 2.0-2.4 tonnes each.

THE OUTCOME

The final outcome can be seen in the image (see below left). If you are interested in finding out more, please contact Raymond Chow (Technical Support Engineer)