Resistivity surveying apparatus.

摘要

A resistivity surveying apparatus comprises a base station (9) and 30 reels (RL1 to RL30). The base station (9) comprises a computer (10) and a resistivity meter (11) having four output terminals. Each reel has a multi-line cable (CB1 to CB30) which includes four resistivity measuring lines for connection to the output terminals of meter (11) and further lines for connection to the output terminals of computer (10). An electrode (EL1 to EL30) which may be driven into the ground is mounted on each reel. In the hub of each reel (RL1 to RL30), there is provided a circuit (CKT1 to CKT30) for connecting the electrode (EL1 to EL30) to one of the resistivity measuring lines under the control of the computer (10).

In operation, the electrodes are driven into the ground at spaced intervals. The free end of one (CB1) of the cables is connected to the base station (9) and the remaining cables are connected in series. The computer (10) then drives the apparatus through a measurement sequence. For each measurement, four electrodes are selected and connected to respective ones of the resistivity measuring lines.