Research On The Revision And Engineering Application Of MC Strength Criterion Based On Elastic Strain Energy

The Mohr-Coulomb strength criterion is the most widely used and most controversial among many strength criteria for geomaterials.Combined with thermodynamics research,the Mohr-Coulomb strength criterion was preliminarily studied from the perspective of elastic strain energy.The specific work is as follows:.?1?The Mohr-Coulomb strength criterion is studied from the perspective of energy dissipation and release principles.The Mohr-Coulomb strength criterion considers that the Poisson's ratio of the material at yield is always equal to 0.5,which may violate the first law of thermodynamics.?2?Based on the principle that elastic strain energy release is the principle of material yielding,the concept of the second invariant of the generalized stress deflection is proposed.From the perspective of energy,the physical meaning of the M-C strength criterion is analyzed,and the generalized Mohr-Coulomb strength criterion is proposed.?3?When the Poisson's ratio is 0.5,the generalized M-C strength criterion degenerates into the M-C strength criterion.This criterion breaks through the assumption that the Poisson's ratio is 0.5 at the time of material failure.?4?Based on the triaxial and true triaxial test research,the theoretical calculation accuracy of the generalized M-C strength criterion was verified by the test data of granite,red sandstone,dolomite and rock salt.The results show that the calculation accuracy of the generalized M-C strength criterion is higher than the M-C strength criterion and the D-P strength criterion.The calculated average errors of granite,red sandstone,dolomite,and rock salt are 0.05,0.03,0.03,and 0.03,respectively.?5?On FLAC^3D,the custom constitutive model was re-developed,the generalized M-C strength criterion was embedded in FLAC^3D,and finally the custom constitutive model was successfully called and run.A slope model is simulated in FLAC^3D.The calculation of the M-C strength criterion does not take into account the effect of the intermediate principal stress and is conservative.The generalized M-C strength criterion calculates the slope safety factor slightly larger than the M-C strength criterion.The accuracy and engineering applicability of the generalized M-C strength criterion are verified.