Evaluation method of shale brittleness based on energy evolution of stress-strain curve

The invention discloses an evaluation method of shale brittleness based on energy evolution of a stress-strain curve. The method comprises the following steps of establishing a shale brittleness evaluation model based on the energy evolution of the stress-strain curve, and evaluating the shale brittleness according to the shale brittleness evaluation model. The evaluation method of the shale brittleness based on the energy evolution of the stress-strain curve provided by the invention overcomes the defect that in the prior art only the influence of a post-peak stress-strain state on the rock mass brittleness is considered and the characterization of pre-peak characteristics on the rock mass brittleness is not considered; and overcomes the defect that a crack initiation stress parameter isintroduced in the prior art, however, due to the complexity of a crack initiation stress and crack initiation strain value taking method and the low value taking accuracy, thus the engineering application difficulty is large.