Single-Hole TRTTM - This technique stems from 'traditional' TRT approach.
Its access to the ground for installation of sources and sensors is
reduced to a single borehole. This technique is particularly useful for
investigation of piles in abutment or pier foundations. It can be used for
imaging structural features of sufficiently well known horizontal
alignment such as line of piles in a bridge abutment.
For piles or other structural features that are more evenly distributed
over wider horizontal area, the survey from at least two, and preferably
from three holes is recommended. This approach allows triangulation and
better focusing of the reflector tracing.
Single-Hole/Parallel Seismic TRTTM is specifically designed for detection
of piles and for measuring their depth and assessing their pattern. Its
effectiveness depends on an adequate access to the pile cap, and the
proper use of repeatable seismic source.
C-TG continues using magnetostrictive actuator driven by a swept frequency
signal as very repeatable and reliable seismic source. This approach
allows transmitting controlled broad-band seismic waves into the ground by
significantly reducing loss of seismic energy in higher frequency range
due to plastic deformation of the ground. In turn, broad-band seismic
waves provide significant improvement in resolution for both TRTTM and
X-PanelTM techniques. This effect is particularly important for imaging
piles as part of bridge abutment and pier foundations to assess their
type, depth, patterns, and overall conditions.
C-TG also relies mainly on using accelerometers and pressure sensitive
hydrophones for detection of seismic signals. Sensitivity of these two
types of transducers is proportional to the second power of the frequency
of seismic vibrations. This type of response provides the most effective
compensation for frequency related exponential attenuation of seismic
waves in the ground.
TomoViewTM is a stand-alone graphic engine software that has capabilities
for data input, survey coordinate verification, imaging local geology and
site conditions, adding comments, and enhancing analysis of processed
ground images for TRTTM in tunnels, X-PanelTM for cross-hole site
investigations, CSLTM for drilled shafts, and SHPS-TRTTM for pier testing.
It also allows exporting 3D files to AutoCAD.