1:45 PM - 3:15 PM
[HTT18-P06] Additional applications of GPR to survey shallow ground structures
Keywords:ground-penetrating radar, surface wave survey, resistivity survey
Geophysical exploration is used to acquire spatial distributions of results from boring and penetration test in shallow ground surveys for the management of river levees and embankments. The surface wave survey and electrical survey method are mainly applied for shallow ground surveys as geophysical exploration techniques. However, the technique of ground-penetrating radar (GPR), which is easier to use, is not so frequently applied to survey shallow ground. This reason is considered that the survey depth of GPR is shallow about from two to three meters and the survey depth is not enough for general ground survey. However, GPR, which cannot acquire information to be wanted to know by itself, can improve the reliability of interpretaion if it will be comvined with surface wave suvey or electircal survey method. This report shows availability of additional applications of GPR in some survey examples in surveys for a transvers section of a river levee and for a embankment filled to a valley.
Surface wave survey and electrical survey method provide us the information of distribution of physical properties, as S-wave velocity and electrical resistivity, in ground. The distribution of physical properties in ground can estimate the type, strength and permeability of soil, which can permit to know internal conditions of ground, which is useful for management. However, the boundaries of the distribution of physical properties cannot become clear due to theoretical limitation. When the ground structure has a clear boundary, the distribution of physical properties, which the surface wave survey and electrical survey method show, must has a wide boundary with a transition area. On the other hand, GPR provide us the information of boundaries between structures. Therefore, GPR records can detect the structural boundary, which surface wave survey and electrical survey method cannot determine. When structural boundaries, if the depth range is only within from two to three meters, will be detected, we can estimate the distribution of structural boundaries using the physical properties which the other geophysical exploration techniques estimate, and the reliability of interpretation of target shallow ground will be improved.
Surface wave survey and electrical survey method provide us the information of distribution of physical properties, as S-wave velocity and electrical resistivity, in ground. The distribution of physical properties in ground can estimate the type, strength and permeability of soil, which can permit to know internal conditions of ground, which is useful for management. However, the boundaries of the distribution of physical properties cannot become clear due to theoretical limitation. When the ground structure has a clear boundary, the distribution of physical properties, which the surface wave survey and electrical survey method show, must has a wide boundary with a transition area. On the other hand, GPR provide us the information of boundaries between structures. Therefore, GPR records can detect the structural boundary, which surface wave survey and electrical survey method cannot determine. When structural boundaries, if the depth range is only within from two to three meters, will be detected, we can estimate the distribution of structural boundaries using the physical properties which the other geophysical exploration techniques estimate, and the reliability of interpretation of target shallow ground will be improved.