Dynamic strength of rocks

Technical Report · Sat Nov 15 00:00:00 EST 1975

OSTI ID:6512929

Handin, J

Experimental work was done on 4 subprojects with potential rock-mechanics applications ranging from earth-quake prediction and control to advanced excavation technology. Measurements of the rate of flow of air through porous Navajo Sandstone with simulated fractures show that as confining (overburden) pressure increases, the fractures (1) have a greater fractional rate of permeability loss than does the rock as a whole, (2) experience the greater inelastic deformation, and (3) become effectively sealed when their permeability approaches that of the whole rock. A cause of the dilatancy that is premonitory to certain earthquakes may be the feather fracturing, associated with frictional sliding on pre-existing faults. In Coconino Sandstone specimens sliding on a sawcut, extension micro-fractures develop near the fault zone. Their abundance increases with increasing normal stress and shear displacement, and they dilate the rock. Frictional sliding of Tennessee Sandstone under cyclic loading has been investigated in an electrohydraulic, servocontrolled testing machine. At confining pressures in the range of 0.5 to 0.75 kb, no stick-slip occurs at low shear-displacement rates of the order of .0001 m/sec, but it does occur at .001.

• Research Organization: Texas A and M Univ., College Station (USA)
• OSTI ID: 6512929
• Report Number(s): AFCRL-TR-75-0594; AD-A-019-145-2GA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
EARTHQUAKES
FORECASTING
SANDSTONES
ROCK MECHANICS
AIR FLOW
CONTROL
DEFORMATION
EXCAVATION
FRACTURES
FRACTURING
MECHANICAL PROPERTIES
PERMEABILITY
PHYSICAL PROPERTIES
SLIDING FRICTION
STRESS ANALYSIS
TESTING
COMMINUTION
FAILURES
FLUID FLOW
FRICTION
GAS FLOW
MECHANICS
ROCKS
SEDIMENTARY ROCKS
SEISMIC EVENTS
580300* - Mineralogy
Petrology
& Rock Mechanics- (-1989)
580201 - Geophysics- Seismology & Tectonics- (1980-1989)