PROCESS AND DEVICE FOR MONITORING THE OCCURRENCE OR SPREADING OF FRACTURES OR CRACKS IN MATERIALS, WORKPIECES, COMPONENT PARTS, STRUCTURES OR FLYING OBJECTS, IN PARTICULAR IN EARTHQUAKE-PRONE REGIONS OR MOVEMENT OF STRATA DURING TUNNELLING

摘要

A process and a device for monitoring the appearance of cracks, fractures, earthquakes and movements of strata exploit the fact that such events are associated with the occurrence of variations in electrical fields. These variations are recorded using a field probe (1) which comprises metallic probe elements (2, 3) that supply a difference amplifier (5) whose output signal (69) is fed to an evaluation unit (10, 11).