In Situ Seismic Investigation, Isabella Project, California
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
Pagination or Media Count:
An in situ seismic investigation consisting of surface refraction seismic, downhole, and crosshole tests was conducted at Lake Isabella, near Bakersfield, California. Compression and shear wave P- and S-wave velocities as a function of depth were determined for the main and auxiliary dams and underlying foundation materials. Results at the main dam indicated four P-wave velocity zones from a surface refraction seismic line located along the crest of the dam. These zones had velocities of a 1,750, b 2,550, c 8,050, and d 18,450 fps, which corresponded to a random fill material, b the central impervious core, c weathered granite, and d fresh granite. Data at the auxiliary dam were given two separate interpretations. The primary interpretation established three basic P- and S-wave velocity zones with respective velocities of a 2,850 and 1,150 fps for the embankment, b 6,600 and 1,600 fps for the foundation to bedrock, and c 12,100 and 3,300 fps for granite bedrock. The alternate interpretation provided a more detailed profile. Nine P-wave and eight S-wave velocity zones were established ranging from a low of 2,450 and 1,000 fps P- and S-wave, respectively to a high of 13,400 fps P- wave and 3,750 fps S-wave for fractured granite.
- Solid State Physics