Fracture process in blasting

Journal Article · Sat May 01 04:00:00 EDT 1971 · Int. J. Rock Mech. Min. Sci.; (United States)

DOI:https://doi.org/10.1016/0148-9062(71)90018-0· OSTI ID:5721350

Kutter, H K; Fairhurst, C

In order to clarify the respective roles of stress wave and gas pressure in the fragmentation of an underground blast the fracture process in the zone immediately around the borehole was studied by separating the 2 principal blast forces analytically and experimentally. In model tests the explosion wave was simulated by the pulse generated by an underwater spark discharge, and the expanding combustion products by pressurized oil. The wave-generated radial fractures around the cavity were investigated in detail and the diameter of the fractured zone was found to approach 6 hole diam for a spherical charge and 9 hole diam for a cylindrical charge. The stress field generated by the pressurized gas in this star cracked cavity was shown to be identical to that of a pressurized and uncracked equivalent cavity whose diameter is equal to that of the fractured zone. A very large region is therefore stressed by the gas, and consequently considerable crack extension can be expected. The influence of boundary conditions, i.e. preexisting fractures, static stress field, and close free surface, on the wave and gas-generated fracture pattern, was investigated. Preexisting-fractures grow to larger lengths than new ones and cause a fracture-free zone in their immediate vicinity. (28 refs.)

• Research Organization: Imperial Coll Sci Technol; Minnesota Univ
• OSTI ID: 5721350
• Journal Information: Int. J. Rock Mech. Min. Sci.; (United States), Journal Name: Int. J. Rock Mech. Min. Sci.; (United States) Vol. 8:3; ISSN IJRMA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
BOREHOLES
CAVITIES
COMMINUTION
DENSITY
ENERGY SOURCES
EXPLOSIVE FRACTURING
EXPLOSIVE STIMULATION
FOSSIL FUELS
FRACTURED RESERVOIRS
FRACTURING
FUELS
MECHANICS
PETROLEUM
PHYSICAL PROPERTIES
ROCK MECHANICS
STIMULATION
STRESS ANALYSIS
STRESSES
TESTING
WELL COMPLETION
WELL STIMULATION