GPR for river dyke - GSB

In Figure 20, there is no continuous layering of either sediment or road materials. This may
be due to plastic nature of the underlying sediment. When heavy traffic moves over the road
it initiates a vibration of the underlying materials. Due to its plastic nature (Density lower than
the overlying sediment), it try to move upward (indicated by red arrow) and destroy the
continuous layering of the sediment as well as road materials.
5 GPR theory revisited: Ground material property, wave speed and propagation
attenuation
There are two types of the material properties, which have effects on the electromagnetic
wave propagating inside the material. One is the relative dielectric constant ε r, and the other
is the resistivity. Tables 1 and 2 show respectively the dielectric constants εr and the
resistivities R for common ground materials.
Table 1: Material dielectric constants
Material Dielectric
Constant εr
Air 1 0.3
Sand 4 0.15
Granite 5 0.13
Sandy soil 6 0.12
Wet clay soil 12 0.09
Fresh water 80 0.03
Table 2: Material resistivities
Wave speed
m/ns
At 100 MHz