Environmental Engineering Reference
In-Depth Information
Rock conditions, since various combinations of rock bits and core barrels are
used, depending on rock type and quality and the amount of recovery required.
●
Surface conditions, which vary from land or quiet water to shallow or deep
water with moderate to heavy swells.
●
Some common sampling tools and their applications to various subsurface conditions
are illustrated in Figure 2.60. The various tools and methods and their applications and
limitations are described in
Table 2.16.
Inspection is provided
to control
1. Correct driving energy
2. Sampler type
3. Sampler condition
4. Sampling sequence
5. Sample identification
6. Sample preservation
7. Condition at sampling depth
1
Sampler type
Splitbarrel (2-1/2" ID)
2
Soil profile
cinder fill
BWL
8
7
Piston
Organic silt
or soft clay
Sampler dropping on
gravel or cinders not
cleaned from casing,
results in high blow
count
Firm to
stiff cloy
Shelby tube
Denison
coreborrel
Hard clay
Soils loosened by
overwashing. Blow
count will be lower
than true count
Piston or
splitbarrel
(1-3/8" ID)
Silty Sand
splitbarrel
(1-3/8" ID)
Sand
splitbarrel
(2-1/2" ID)
Sand under
hydrostatic pressure
plugging casing. Blow
count will be higher
than true
Gravel
Corebarrel-
carboloy bit
Soft rock
8. Groundwater measurements
9. Depth of boring
10. Sample recovery
−
percentage
Hard rock
Corebarrel-
diamond bit
FIGURE 2.60
Common sampling tools for soil and rock and their application.
