Device for evaluating integrity of underground structure by using electromagnetic wave

A device for evaluating integrity of an underground structure by using electromagnetic waves, the device comprising:

• a plurality of main reinforcing bars arranged in a vertical direction in an underground structure;
• a plurality of measurement cables extending in the vertical direction to be adjacent to the main reinforcing bars, respectively;
• at least one impedance change unit which is provided on each of the measurement cables, is electrically connected to the measurement cable, and has a characteristic impedance different from a characteristic impedance of the measurement cable;
• and
• an electromagnetic wave measurement unit for detecting a change point of a characteristic impedance as a defect point of the underground structure by providing an electromagnetic wave by using, as a signal transmission line, one of the plurality of measurement cables and one of the plurality of main reinforcing bars, or one pair of measurement cables selected from the plurality of measurement cables,
• wherein the electromagnetic wave measurement unit determines a defect position in the vertical direction of the defect point by using, as a reference point, a point at which a characteristic impedance is changed by the impedance change unit.