Rock brittleness is an important parameter to characterize failure characteristics of rocks.An accurate brittleness evaluation method is of great significance to geotechnical engineering.In the present study,we primarily summarized a considerable number of methods that were widely used to characterize rock brittleness based on the stress-strain curve.Then,three types of rocks were used to analyze the energy evolution law and brittleness index of the pre-peak and post-peak during rock failure.The results indicate that the dissipative energy evolution law of sandstone,marble,and granite specimens under uniaxial compression presents"(ɔ)"type,"S"type,and"L"type respectively;At the pre-peak stage,the brittleness index of marble is the smallest and that of the granite is the lar-gest;At the post-peak stage,the brittleness index of sandstone is the same as that of granite,and that of marble is the smallest;The full stress-strain curve can better characterize the brittleness pre-peak and post-peak in the process of rock failure based on the energy evolution.While the pre-peak and post-peak indexes cannot be simply mathematically characterized into one index.The correlation between the pre-peak and post-peak rock brittleness in-dexes is not clear.The combined brittleness index cannot effectively characterize the change of the pre-peak and post-peak brittleness at the same time.Pre-peak and post-peak brittleness indexes should be separately considered.The brittleness characteristics and laws of the pre-peak and post-peak should be separately characterized and ana-lyzed.
维普
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