METHOD FOR NON-DESTRUCTIVE TESTING OF ANCHOR LENGTH IN ROCK MASS USING ELECTROMAGNETIC SOUNDING Russian patent published in 2023 - IPC E21D20/00 

FIELD: electromagnetic sounding.

SUBSTANCE: method for monitoring the length of an anchor in a rock mass using electromagnetic sounding. The method involves creating an electromagnetic field in a rock mass by connecting the phases of an alternating current generator to the rock mass. One of the generator phases is connected to the protruding end of the anchor rod. After that, a calibration dependence is obtained, from which the length of the anchor is determined. The calibration dependence is obtained under natural conditions on a sample section of the rock mass by measuring on a set of calibration anchors of different lengths placed in the rock mass. To measure at each length, a different phase of the generator is connected to a counterweight consisting of several parts. The method also includes connecting parts of the counterweight to each other. The method also includes measuring the electrical capacitance C between the anchor rod and the counterweight. After that, a calibration dependence (LC) is built between the length of the anchor L and the capacitance C. After that, the parts of the counterweight are separated and the capacitance C₀ is measured between two of them. Then they move on to measuring the length of the anchor in other places. Then the capacitance C_i between the i-th anchor and the combined counterweight is measured. Then the parts of the counterweight are separated from each other and the capacitance C_0i between two of them is measured.

EFFECT: increasing the accuracy of anchor length control.

1 cl, 2 dwg