Pozorna "kontrowersja": mechaniczne zmęczenie czy twardnienie skał po ich wydobyciu ze złoża

Abstract

AN APPARENT CONTROVERSY: MECHANICAL FATIGUE OR HARDENING OF ROCKS AFTER THEIR MINING Summary An apparent controversy between mechanical fatigue and hardening of rocks after their excavation from pits to daylight was elucidated. There are 5 phases of strength changes in time samples after their excavation: the first phase, the main phase and the late phase of hardening, that are characterized by the strenght increase in time; the final phase of hardening, which can be described by some strenght stability of the highest values and at last the phase of the showing mechanical fatigue under an influence of atmospheric factors changes (especially the atmospheric pressure changes), that cause rock disintegrations even to silt fraction after some long time. It was mentioned too, that depends on the rock nature and passage of time and strength value changes before and after excavation of rock samples, durations of particular phases and samples disintegration character are different.