4.4 Preparation of original sample and sieving (Step 1)
4.4.1 Preparation of original sample
Original sample is prepared in a container. The quantity of original sample required for the test will vary depending on the grain size distribution. Enough quantity of original sample should be prepared to obtain more than 8 kg of sieved sample. After removing large lumps such as a head of infant from original sample, 15 kg is enough, in general.
4.4.2 Sieving (see photo 9)
The sieve is prepared at the top of stacked containers and rubber gloves are put on hands. The container including original sample should not be stacked. The original sample is put on the sieve and sieved sample is stored in the container by being passed through the sieve manually.
When much fine particles remain on the sieve, the moisture content of sieved sample become lower. During sieving, therefore, particles finer than the mesh size remaining on the sieve should be as little as practical, not to decrease the moisture content of the sieved sample.
The quantity of sieved sample stored in the container should be more than 8 kg.
4.5 Measurement of maximum cone penetrating force (Step 2)
The procedures described in this paragraph are repeated three times for a sieved sample.
4.5.1 Forming specimen in the mould (Step 2.1)
Prior to cone penetration test, the specimen is formed in the mould by the following sub-steps:
.1 The mould is assembled by connecting the bottom plate, the cylinder and the collar, properly (see photo 4);
.2 The sieved sample is filled and tamped in the mould being divided into five layers. Approximately one fifth of the whole sieved sample to be filled in the mould is inserted into the mould and the increment is tamped uniformly over the surface of the increment. Tamping is executed by dropping the hammer 60 times through the guide, 0.45 m each time, for each increment (see photo 10). The dropping height, 0.45 m, is achieved by pulling up the handle of hammer to the end of the guide and releasing the handle while the bottom of the guide is put on the surface of the sieved sample. The performance is repeated for all five layers, respectively; and
.3 When the last layer has been tamped, insert a suitable flat bar or the straight edge between the sieved sample and the collar of the mould and move the flat bar along inside the collar, to separate the sieved sample from the collar. After separating the sieved sample from the collar, the collar is removed (see photo 11). Then the sieved sample is leveled off along the brim of the mould using the straight edge (see photo 12), to adjust the volume of specimen. Removed sieved sample is put back in the container for the sieved sample.
The quantity of each increment, that is the sieved sample for each layer, is around 1.6 kg. To control the total amount of sieved sample inserted in the mould, it is recommended to fill the sieved sample along the brim of collar by pushing the sieved sample manually without tamping, at the insertion of the sieved sample for the last (5th) layer.
4.5.2 Cone penetration test (Step 2.2)
Two persons are needed for cone penetration test. One person (the tester) penetrates the cone into the specimen and the other person observes the penetration depth and notice the penetration depth to the tester. The maximum cone penetrating force is measured by the following sub-steps.
.1 The tip of the cone is set on the surface of the specimen approximately at the center;
