Langefors and Kihlström, 1978 c

crack-, fracture-or fissure propagation velocity and fracture growth velocity (m/s)

* c d velocity of detonation (m/s)

confined velocity of detonation (m/s) c

non-ideal detonation velocity (m/s) c

dssteady state velocity of detonation (m/s) c

hydraulic conductivity or hydraulic permeability (m/s) * c

P-wave-, sonic-or longitudinal wave velocity (m/s) c

P-wave velocity measured in the laboratory often in drill cores (m/s) c

Po P-wave velocity in homogeneous material free of prestresses and without natural physical discontinuities or blast induced cracks (m/s)

Rayleigh wave propagation velocity (m/s) c

S-wave – or transverse wave propagation velocity (m/s) c

sonic wave velocities (m/s)

subsonic speed (m/s) c

c t transient velocity (m/s)


* D drillhole-or borehole deviation (degree, % or m/m) D modulus of deformation (MPa) D

(degrees, mm/m or %) D

D c collaring deviation error in drilling (m or %)

D e equivalent support dimension (m)

D f fractal dimension (dimensionless)

D fs surface fractal dimension (dimensionless)

D i blast damage index (BDI) defined Yu and Vongpaisal, (dimensionless)

D ib blast damage index or damage index at blasting defined by

Paventi (dimensionless) D

setting-out deviation (error) in drilling (m) D

D T total borehole deviation or drilling accuracy (degrees, m or %)

< 1 (dimensionless) * d diameter (mm) d diameter of borehole or blasthole (mm or m) d

d c diameter of cartridge (mm or m)

critical diameter of cartridge (mm or m) d

external diameter (mm or m) d

diameter (mm) d

d o outside diameter or set outside diameter of a bit (mm)

optimal blasthole diameter (mm or m) d

diameter of plastic zone after crater blasting (m) d

diameter of rupture zone after crater blasting (m) d

d tc diameter of true crater after crater blasting (m)


E east (cardinal point) * E modulus of elasticity or Young’s modulus (MPa)

E d dynamic modulus of elasticity or dynamic Young’s modulus (MPa)

decrease Young’s modulus (MPa) E

eeffective Young’s modulus or effective modulus of elasticity (MPA) E

flexural modulus of elasticity for core specimen (MPa) E

quasi dynamic modulus of elasticity or quasi dynamic Young’s modulus (MPa) E

E t modulus of rupture in torsion (MPa)

e dilatation or volumetric strain (dimensionless) * e natural logarithm (dimensionless) * e void ratio (dimensionless) e


* F force, load or thrust (N or MN) F shape factor (dimensionless) F

F bi force on the drill bit or bit load (N)

F c crack extension force (N)

F f feed force on drill machine at drilling (N)

maximum force (N or MN) F

F t tangential force (N or MN)

* f confinement, degree of confinement, fixation factor (dimensionless) f factor or coefficient (dimensionless) * f frequency (Hz) f

b degree of confinement dependent on the bench slope in blasting (dimensionless)

f bi inclination factor for the blastholes (dimensionless)

boulder frequency (No./1000 t or No./1000 m3) f

f d frequency of discontinuities (No./m)

mean frequency of discontinuities (No./m) f

f i frequency of incoming blast wave (Hz)

frequency of joints (No./m) f

3-D volume density of joints (No./m3) f

joint plane spacing (dimensionless) f

RQD-value (Rock quality designation) (dimensionless) * f

(Hz or cycles/s)

natural frequency of a building (Hz) f

f o overbreak factor (%)

seismicity (No./year and 100 km2) f

stress reduction factor (dimensionless) f

f x ground vibration frequencies induced by a blast (Hz)


* G shear modulus of elasticity, modulus of elasticity in shear, rigidity modulus or modulus of rigidity (MPa)

G strain energy release rate (crack resistance, crack resistance energy, energy of rupture, fracture energy or fracture surface energy) (J/m2)

critical strain energy release rate (J/m2 orMJ/m2) G

strain energy release rate for a mode I loaded crack (J/m2 orMJ/m2) G

loaded crack, respectively (J/m2 orMJ/m2)

* g acceleration due to gravity (m/s2)


* H height (m) H height of specimen or beam (mm or m) H

height of abutment (m) H

H d height of tunnel, drive, crosscut, adit, incline or decline (m)

height of draw (m) H

height of lip of crater or crater lip height (m) H

h draw height (m) h


* I electrical current (A) * I impulse or momentum (Ns) * I movement of inertia of mass (kgm2) I sound pressure or acoustic intensity (W/cm2) I

block size index (m)

blasting index (dimensionless) I

coal dust index (%) I

I D density index (dimensionless)

joint intensity, number of joints per unit of area (No./m2) I

joint intensity, total joint trace length per unit of area (1/m) I

I L liquidity index (dimensionless)

maximum (recommended) firing current (A) I

I p drilling index

I P plasticity index (mass-%)

I rc rock quality index regarding drillability (kPa·min/m)

* I s point load strength or point load index (Pa or MPa)

I st stray current (A)


J a joint alternation number (dimensionless)

J d joint length density (1/m2)

J n joint set number (dimensionless)

J r joint roughness number (dimensionless)

J v number of joints per m3 orvolumetric joint count (No. of joints/m3)

J w joint water reduction factor (dimensionless)


* K bulk modulus or incompressibility (the inverse of compressibility) (Pa) K Fischer constant (dimensionless) K number of cycles at breakage of structure (No.) K

K c scaled strain intercept (dimensionless)

K d dynamic bulk modulus (MPa)

K o number of cycles when damage of a structure starts (No.)

K s shear stiffness (MPa)

K I , K

loaded cracks (MN/m3/2) * K

loaded crack (MN/m3/2) K coefficient of permeability or permeability coefficient (m/s).