Laserfiche WebLink
<br /> <br />EM 1110-2-1913 <br />31 Mar 78 <br /> <br />Name <br /> <br />b. Continuous <br />vibration <br />(Continued) <br /> <br />2. Electrical methods <br />a. Resistivity <br /> <br />b. Equipotential <br />mapping <br /> <br />Table 2-4. <br /> <br />(Continued) <br /> <br />Principle <br /> <br />Based on the difference in <br />electrical conductivity <br />or resistivity of strata. <br />Resistivity of subsoils <br />at various depths is <br />determined by passing a <br />known current between two <br />electrodes and measuring <br />the potential difference <br />between two intermediate <br />electrodes. Resistivity <br />is correlated to material <br />type <br /> <br />Location of lines of equal <br />potential around a <br />current electrode <br /> <br />2-8 <br /> <br />. <br /> <br /> <br />Use <br /> <br />the natural <br />iod of vibra- <br />n for founda- <br />ns of vibrat- <br />structures <br /> <br />.. <br /> <br />to determine <br />ths up to <br />ft of hori- <br />tal subsurface <br />ata. Princi- <br />applications <br />investigating <br />dations of <br />s, levees, and <br />er large <br />uctures, par- <br />ularly in ex- <br />pI ring granular <br />ri'er channel <br />de osits or bed- <br />k surfaces. <br />o used to mea- <br />e depth to <br />rated zones <br />aquifers <br /> <br />Deli eation of <br />ver ical bound- <br />ari s and zones <br />of imited hori- <br />zon al extent. <br />Can trace lines <br />of ater flow or <br />lac te bodies <br />suc as clay <br />plu s <br /> <br />. <br /> <br /> <br />. <br />