GPR for river dyke - GSB

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Figure 18: Results of GPR measurement road on Madhupur Clay deposit In Figure 18, there are some layerings at the upper part. These layering are due to the minute variation of Madhupur Clay. There is a channel fill like deposit in between 75 and 45 trace. The depth of the filling materials is about 12feet. The channel is filled by sandy material which is confirmed by the depth penetration of the radar. There is also a warping near to the No 10 trace. It seems that the left side of warping push upward compared to the right side. The left site of the warping is more sandy than the right side. Presence of warping in the radar gram indicates that the site has effected by neo-tectonic activity. Figure 19: GPR survey, road on depression deposits Figure 20: Results of GPR measurement road on depression deposit
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
Page 1 and 2: GOVERNMENT OF THE PEOPLE’S REPUBL
Page 3 and 4: Summary The Norwegian Geotechnical
Page 5 and 6: 1 Introduction The Geological Surve
Page 7 and 8: Figure 2: GSB personnel operating t
Page 9 and 10: Figure 5: Radargram for the test on
Page 11 and 12: new pitch road has been made. The t
Page 13 and 14: 4.2.3 GPR survey on Prottasha bridg
Page 15: Figure 15 shows the radargram for G
Page 19 and 20: Kontroll- og referanseside/ Review
Page 21: Kontroll- og referanseside/ Review

GPR for river dyke - GSB

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