Study on the method of energy evolution of rock under uniaxial compression test

For investigation evolution of energy of rock during the unconfined compression, using same loading rate were carried out uniaxial cycle loading and unloading tests, uniaxial graded loading and unloading tests, and unconfined compression tests. Through the analysis of experimental phenomena shows that the number of cycles has little effect on elastic energy. It indicates that fatigue damage has no effect on elastic energy of rock. Further comparing the elastic energy of the uniaxial cyclic loading and unloading tests and the uniaxial cyclic graded loading and unloading tests, it can be found that their elasticity energy approximately when the loads are the same. Based on above elastic energy studying, can considered that the elastic energy of the rock does not change when the load is greater than or equal to the previous load. Therefore, their elastic energy are the same when the load of unconfined compression are equal to the load of unloading point of the uniaxial graded loading and unloading tests. Based on the above analysis results, the energy real-time evolution before the peak strength of unconfined compression is studied. The method provides a new idea for real-time evolution of energy before the peak strength of rock during the unconfined compression.