Rock fill Settlement Test

Material.
The material used for rockfill embankments shall consist predominantly of rock fragments of such size that the material can be placed in layers of the thickness prescribed, conforming to the following requirements:

Maximum particle size….. 2/3 loose layer thickness
Passing 0.6 mm (No. 30 Sieve)….25% maximum
Uniformity coefficient, Cu 5 minimum, where
Cu = D60/D10
*D60 = the particle size at which 60% passes
*D10 = the particle size at which 1 0% passes

Maximum Thickness of Layer                        Minimum Roller Mass on Drum
(Loose Measurement)                                                (kilogram/unit width,)
Centimeters
                40                                                                  2300-2900
                60                                                                  2900-3600
                 80                                                                 3600-4300
                100                                                                4300-5000

** For multiple roller, this shall be assessed on the high axle load.

Compaction:-

The test section shall be of sufficient dimensions to permit the establishment of at least twenty (20) leveling points on a five (5) meters square (5 sq.m.) grid, and no fewer than three (3) points on any line and no point less than three (3) meters from the edge of the layer.
Compaction shall then commence with a minimum of three passes of a vibratory roller. 
Short lengths of painted steel bars hammered flush with the surface of the rockfill have been found suitable for this purpose. A level reading is taken at each leveling point on top of a movable thirty (30) centimeters square flat steel plate. A hole drilled in the center of the plate will enable a visual check to be made that the plate is located centrally over the bar each time.
Further readings are then taken at the leveling points. After two (2) additional passes with the roller, if the average settlement is less than one percent (1 %) of the average compacted layer thickness, or as determined by the Engineer, the rockfill compaction test is completed.
If the average settlement is more than one percent (1 %), two (2) additional passes of the roller are required and the leveling procedure is repeated. If the average settlement is now less than one percent (1 %), the test is completed. If not, this step is then repeated.

Some picture shows the ROCK FILL SETTLEMENT TEST.

Initial reading of 5 squire m. with 20 test points

Initial reading of 5 squire m. with 20 test points

Initial reading of 5 squire m. with 20 test points

Initial reading of 5 squire m. with 20 test points

Initial reading of 5 squire m. with 20 test points

After initial reading made 3 passes with roller

After initial reading made 3 passes with roller

After initial reading made 3 passes with roller

Final reading after 3 passes

Report Sheet :-