Estimation Of Equivalent Mohr-Coulomb Parameters Of Slope Based On Hoek-Brown Criterion

When using the non-linear Hoek-Brown strength criterion to determine the slope equivalent Mohr-Coulomb parameter cohesion c and internal friction angle?,the key is to determine the maximum value of the minimum principal stress?_3max on the potential failure surface of the rock slope.At present,there have been some researches on how to obtain this value,but there are still some problems.Based on the existing problems in the research,this paper uses the strength reduction method in the finite element analysis method to calculate various rock mass properties and slope shape models.Based on the determination of the potential failure surface position of the slope,the elastic stress Calculation and analysis have determined the maximum value of the minimum principal stress?_3max on the failure surface.By comparing with the calculation results of the limit equilibrium method,the reliability of the aforementioned method is verified.Analysis of the calculation results of rock slope models under 425 different working conditions shows that the value of?_3max is most affected by the slope angle?,followed by the geological strength index GSI,followed by the rock parameter m_i and the uniaxial rock mass.The compressive strength?_ci,and the disturbance coefficient D has the least influence.This paper sorts out and analyzes the calculated 425 sets of data through the analysis results,and proposes four schemes for estimating the value of?_3max.Comparative analysis shows that the fitting formulas of scheme 3 and scheme 4 are highly correlated,and the predicted value of scheme 4 The error is minimal.Using the?_3max value obtained by the formula 4 and the formula proposed by Hoek et al.,the corresponding equivalent shear strength parameters,the cohesive force c and the internal friction angle?,are obtained.The results show that the accuracy of the proposed estimation formula is higher than that of the existing methods.At the same time,the actual engineering case is verified and calculated using the method in this paper.The results show that the obtained stability coefficient is almost the same as the stability coefficient calculated using the Hoek-Brown criterion,which further proves the reliability of the method proposed in this paper.