GPR for river dyke - GSB

Figure 15 shows the radargram for GPR measurement on the highway beside Prottasha
bridge. From this figure one can clearly see that the ground structure of the section between
two yellow lines (trace number 125 to 265) is different to the adjacent sections at both sides.
This is the section when the GPR moves close to the bridge connecting road. The red lines
show the reflections from a shallow layer (brick to sand interface?). At trace numbers 30, 85,
330, there may be reflections from pipes or cables under the highway.
Figure 16 shows the working environment when testing on the main dike which is a highway.
Figure 16: GPR test on a heavy traffic road connected to Prottasha bridge
4.3 GPR tests on road
GPR Survey was performed at two places on Tongi-Pubail highway. The first survey was
carried out road on Madhupur clay deposits which fall within 23º56′07″ N to 23º56′06″N
Latitude and 90º28′19″ E to 90º28′19″ E Longitude (Figure 17). The second survey was road
on depression deposit in between 23º54′54″ N to 23º54′51″N Latitude and 90º25′28″ E to
90º25′23″ E Longitude (Figure 19). In this survey, 1.2m antenna has been used. The total
length of survey area was about 203m and 133m respectively.
Figure 17: GPR survey, road on Madhupur Clay deposit