System and method for electromagnetic monitoring of active cracks in concrete dam

A method for electromagnetic monitoring of active cracks in a concrete dam, comprising:

• selecting areas to be monitored based on a distribution pattern of the active cracks, arranging at least four electromagnetic signal acquisition devices uniformly on a concrete dam surface, and recording spatial locations of the electromagnetic signal acquisition devices;
• obtaining by an electromagnetic monitoring sensor, three-axis magnetic field components in a spatial electromagnetic radiation field of a sampling point in the selected areas;
• in response to filtering interference data caused by spatial electromagnetic radiation noises out of the three-axis magnetic field components, obtaining by an amplifier filter circuit and a data acquisition processor, electromagnetic radiation signals generated by the active cracks;
• sending the electromagnetic radiation signals to a main control device via wireless communication devices;
• obtaining by a central processing unit (CPU), a time of sending each electromagnetic radiation signal to the main control device, an amplitude, a frequency and a duration of each electromagnetic radiation signal;
• positioning a spatial location of an active crack by obtaining arrival time differences and amplitudes of electromagnetic radiation signals received by the main control device from four electromagnetic signal acquisition devices based on electromagnetic radiation signal propagation law and signal attenuation law;
• and
• determining a size of the active crack by comparing an amplitude, a frequency and a duration of each electromagnetic radiation signal from four electromagnetic signal acquisition devices based on a correspondence between electromagnetic radiation signal characteristics and active crack characteristics.