Environmental Engineering Reference
In-Depth Information
FIGURE 2.38 (b)
Cone penetrometer test equipment: (b) various cone sizes. (Courtesy of ConeTec.)
The seismic cone penetration test (SCPT) (Figure 2.39a) combines the piezocone with the
measurement of small strain shear wave velocities (P and S waves). A small geophone or
accelerometer is placed inside a standard cone, and seismic wave velocities are measured
during pauses in cone penetration. A hammer blow to a static load on the surface can pro-
vide the shear wave source. Explosives can be used offshore or the “downhole seismic
test” onshore. The results have been used for evaluating liquefaction potential (Robertson,
1990).
The active gamma penetrometer (GCPT) (Figure 2.39b) measures in situ soil density. The
test is particularly important in clean sands, that are difficult to sample in the undis-
turbed state.
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