Soil classification - Geotechnical Investigation and Design Tables - page 19

entries. These devices are useful in mapping cuttings and for relatively slow rock
coring on site, or for cores already drilled.

2.3 Drilling information
The table shows typical symbols only. Many consultants may have their own variation.

Table 2.3 Typical drilling data symbols.

Symbol Equipment

BH Backhoe bucket (rubber tyred machine)

EX Excavator bucket (tracked machine)

HA Hand auger

AV Auger drilling with steel “V'' bit

AT Auger drilling with tungsten carbide (TC) bit

HOA Hollow auger

R Rotary drilling with flushing of cuttings using

RA - air circulation

RM - bentonite or polymer mud circulation

RC - water circulation

Support using

C - Casing

M - Mud

W - Water

2.4 Water level
•

The importance of this measurement on all sites cannot be over-emphasised.

•

Weather/rainfall conditions at the time of the investigation are also relevant.

Table 2.4 Water level.

Symbol Water measurement

Measurement standing water level and date ∇

∇

Water noted

Water inflow

Water/drilling fluid loss

2.5 Soil type
•

The soil type is the main input in describing the ground profile.

•

Individual particle sizes < 0.075mm (silts and clays), are indistinguishable by the

eye alone.

•

Some codes use the 60 m instead of the 75 m, which is consistent with the

µ µ

numerical values of the other particle sizes.