Engineering Rock Mechanics

xvi Units and symbols

Symbol Quantity Name of SI unit Dimensions
SI unit of unit
K
K
knr ks

L

1, m, n

m

N

P

PB, ps

PL

Q

Q

r

MR

RQD

RQDt

S S S S t I U

ucs

V

W

x, yt z

xbar

Xbar

Z

2

hydraulic conductivity

stiffness

fracture normal stiffness,

fracture shear stiffness,

length

Cartesian axes

coefficient in Hoek-Brown

strength criterion

number in sample

pressure

breakdown pressure, shut-in

pressure

point load index value

flow rate

rock mass quality rating

radius

rock mass rating value

rock quality designation, YO

rock quality designation for

threshold value r

elastic compliance

elastic compliance matrix

coefficient in Hoek-Brown

strength criterion

sample standard deviation

threshold value for RQD

thickness

displacement

unconfined compressive

strength

displacement

weight

Cartesian axes

mean fracture spacing

sample mean

depth

standard normal variable

pascal, Pa

pascal, Pa

pascal, Pa

m s-l LT-'

m-2 kg s-~

m L

kg s-~ MT-

L-2MT-

N m-2, m-' kg L-'MT-

N m-2, m-' kg s-~ L-'MT-

N m-2, m-' kg s-~ L-'MT-

m3 s-l L3T-'

m L

lacsap, Pa-' N-' m2 , m kg-' s2 LM-'T

lacsap, Pa-' N-' m2 , m kg-' s2 LM-'T

m L

m L

m L

N m-2, m-' kg s-~ L-'MT-*

m L

kg m LMT-~

m L

pascal, Pa

m L

The convention for writing symbols is as follows.

Symbols for tensor quantities should be in sans serif bold italic form,

Symbols for vector quantities should be in bold italic form, e.g. F.

Symbols in Latin or Greek should be in italic form, e.g. x.

e.g. S.