Investigation Methods and Procedures - Geotechnical Engineering Investigation - page 108

Retainer basket type
Inner tube shoe

2 ft or 5 ft liner, stainless steel, brass or plastic

Outer tube bit
Saw tooth or carbida insert

FIGURE 2.66
Denison core barrel for hard soils. (Courtesy of Sprague and Henwood, Inc.)

FIGURE 2.67
Removal of the cutting bit from the Denison core barrel after coring cemented silty sands.

retrieved from the hole, the cutting bit removed from the barrel (Figure 2.67), and the thin
liners, retained in the inner tube by wall friction or a basket-type retainer, are removed.

Pitcher Sampler
The operation of the Pitcher sampler is similar to that of the Denison core barrel except
that the inner barrel is spring-loaded and thus provides for the automatic adjustment of
the distance by which the cutting edge of the barrel leads the coring bit ( Figure 2.68) .
Because of adjusting spring pressure, the Pitcher sampler is particularly suited to sam-
pling deposits consisting of alternating soft and hard layers.

2.4.3 Miscellaneous Soil-Sampling Methods

Wash Samples
Completely disturbed cuttings from the hole advance operation carried to the surface by
the wash fluid and caught in small sieves or by hand are termed washed samples. Value
is limited to providing only an indication of the type of material being penetrated.