Fill specifications - Geotechnical Investigation and Design Tables - page 220

17.13 Durability of breakwater
•

The durability should be assessed on the material function.

•

Primary armours have a higher durability requirements than a secondary armour.

Table 17.13 Durability requirements for a breakwater.

Parameter Stone core Stone armour Comments

Secondary Primary

Rock weathering DW DW/SW SW/FR Field assessment

RQD 50% 75% 90% for suitability > > >

Joint spacing 0.2 m 0.6 m 2.0 m

> > >

Water absorption 5% 2% 1% Control testing

< < <

Aggregate crushing value

>

25%

>

20%

>

15%

Uniaxial compressive strength 10 MPa 20 MPa 30 MPa > > >

Los angeles abrasion 40% 30% 20% < < <

Magnesium sulphate soundness 15% 10% 5% Loss < < <

Nominal rock sizing 100 kg 500 kg 1000 kg > > >

17.14 Compaction requirements
•

The placement density and moisture content depends on the material type and its
climatic environment.

•

Material with WPI 2200 are sensitive to climate, and can wet up or dry back, if

compacted at OMC and MDD. This results in a change of density and moisture
content with an accompanying volume changes.

>

Table 17.14 Acceptance zones for compaction.

Property Typical application Density (wrt MDD) Moisture content

Shear strength - High Pavement High at or MDD Low, at or below OMC >

Permeability - Low Dams, Canals MDD, but governed by High, at or above OMC

placement moisture
content

Shrinkage - Low General embankment fill Low but 90% MDD At EMC >

in dry environments

Swelling - Low General embankment fill Low but 90% MDD At EMC >

in wet environments

- EMC - Equilibrium Moisture Content.
- WPI - Weighted Plasticity Index.

17.15 Earthworks control
•

Earthworks is controlled mainly by end - result specifications, ie measuring the
relative compaction.