Environmental Engineering Reference
In-Depth Information
FIGURE 2.86
Core recovery of about 90% in fractured diorite grading to gneiss; RQD about 40 to 70%. Coring with NX
double-tube swivel-type barrel.
Preservation, Shipment and Storage
Split-Barrel Samples
Carefully place intact uncontaminated short cores in wide-mouth jars of sufficient size (16
oz) to store 12 in. of sample. The samples, which may be used for laboratory examination,
should not be mashed or pushed into any container; such action would result in complete
loss of fabric and structure. The jar caps should contain a rubber seal, be closed tightly, and
be waxed to prevent moisture loss. Liner samples are preserved as thin-wall tube samples.
Thin-Wall Tube Samples
Remove all cuttings from the sample top with a small auger and fill the top with a mixture
of paraffin and a microcrystalline wax such as Petrowax, applied at a temperature close to
the congealing point. Normal paraffin is subjected to excessive shrinkage during cooling
and should not be used or an ineffective moisture seal will result. The top is capped, taped,
and waxed.
Invert the tube, remove a small amount of soil from the bottom and fill the tube with
wax. Cap, tape, and wax the bottom.
Tubes should be shipped upright, if possible, in containers separating the tubes from
each other and packed with straw.
In the laboratory, tubes that are not to be immediately tested are stored in rooms with con-
trolled humidity to prevent long-term drying. Soil properties can change with time; there-
fore, for best results, samples should be tested as soon as they are received in the laboratory.
Rock Cores
Rock cores are stored in specially made boxes (Figure 2.86) in which wooden spacers are
placed along the core to identify the depth of run.
Extrusion of UD Samples
Thin-Wall Pushed Samples
To obtain specimens for testing thin-wall tube, samples should be extruded from the tube
in the laboratory in the same direction as the sample entered the tube, with the tube held
