Drilling & Sampling Technologies - Sonic Drilling
Sonic drilling is used for continuous sampling and
monitoring well installation in unconsolidated and soft/fractured
bedrock. The primary benefits of this technology are that very rapid
drilling rates are possible combined with reduced volumes of waste.
Recent improvements in equipment design should lead to increased use in
the future.
A sonic rig uses an oscillator or head with eccentric
weights driven by hydraulic motors to generate high sinusoidal force in a
rotating pipe drill. The frequency of vibration (generally between 50
and 120 cycles per second) of the drill bit or core barrel can be varied
to allow optimum penetration of subsurface materials. A dual string
assembly allows advancement of casing with the inner casing used to
collect samples. Small amounts of air and water can be used to remove
the material between the inner and outer casing. When a drill bit is
used, most of the cuttings are forced into the borehole wall. A
thin-wall or split-spoon sampler can be used to contain continuous
samples. Sonic drilling is also referred to as vibratory drilling
and rotosonic drilling.
Sonic Drilling: Rocks Drilled Out and Through
Sonic Drilling Vibratory Head
Retrieval of the Core Sample
Track Mounted Sonic Drilling Apparatus
Cored Rock Fragments (Cylinder Dimensions are 1.5"D x 6"L)
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