Analysis of cross-hole seismic measurements in columnar-jointed basalt
A series of cross-hole acoustic measurements have been performed in a columnar-jointed basaltic rock mass around an underground opening mined by the drill-and-blast method. The purposes were to evaluate the rock mass characteristics around the opening; to determine the zone of blast damage; and to evaluate seismic methods for anomaly detection ahead of mining in this type of rock. Repetitive pulses of compressional (P) and shear (S) were propagated through the rock mass to a receiver sonde. The results indicate considerable reductions in P- and S-wave velocities at distances less than 2 m from the face. Clearly these low values are associated with blast damage. Beyond 2 m, the velocities in a vertical direction indicate almost constant values. The velocities in the horizontal direction beyond 2 m appeared erratic, but showed a general tendency to increase as a function of distance from the fact. Results of the spectral analyses of the received signals indicated that Q-values were strongly influenced by the vertically-oriented sets of joints.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6092249
- Report Number(s):
- LBL-17975; ON: DE85007618
- Country of Publication:
- United States
- Language:
- English
Similar Records
Experimental studies of elastic-wave propagation in a columnar-jointed rock mass
Cross-hole acoustic surveying in basalt
Related Subjects
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
ACOUSTIC MONITORING
BASALT
BLAST EFFECTS
BOREHOLES
CAVITIES
DATA
EXPERIMENTAL DATA
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
IGNEOUS ROCKS
INFORMATION
MONITORING
NUMERICAL DATA
ROCKS
SEISMIC SURVEYS
SURVEYS
VELOCITY
VOLCANIC ROCKS
WAVE PROPAGATION