The dynamics of the acoustic emission with water initiation

The long-term experiments on the biaxial compression of the models prepared from basalt sand, crushed limestone, and cement are carried out. The volume of the models exceeded 4 × 103 cm3. At different grades of load, water was infused into the model through the borehole. The volume of the infused water was less than 0.1% of the volume of the model itself. Water infusion resulted in the activation of the acoustic emission with a particular time lag. The initiation of the acoustic emission is connected with the local reduction in the strength and with the increase in the stresses near the metastable, which does not contradict the trigger mechanism. The hypocenters of the sources of acoustic signals initiated by water infusion lay in the vicinity of the boreholes. Within the time interval between weak events, pulses with higher energy appeared, which has an analogy with the swarm of earthquakes. The growth and extinction of the acoustic emission after the stepwise additional load and with the initiation by water infusion is significantly different. In the first case, the Omori law is obeyed. In the second case, the intensity of acoustic emission has a pronounced maximum. The equations of the kinetic concept of strength in solids make it possible to describe the dynamics of the acoustic emission caused by water infusion.