A vector diagram to determine anomaly conditions in a thin layer

Drainage pavement has some beneficial functions. But it also has a disadvantage likely to lose its functions by having the ports become packed by fies such as soil and sand. We need to learn the condition, which are the portion and the degree of pacldng, in order to make a plan of appropriate recovery works. Unpacked and packed conditions can be easily identified, if uniformly packed, by reflectivity of GPR pulse from the surface. But the actual packing condition is too complex to distinguish inner reflections. We made a concept by numerical simulation that the interfered compound reflection reflecting inner irregular conditions has characteristics due to pulse lengths. The simulation showed that the portion and the degree of packing could be determined by combination of each reflectivity by use of 0.6711s and 1.33 ns pulses. Experimental and field measurement dem,onstrated that this method is practically useful.