Due to the importance of study of mechanical parameters of rock mass discontinuities

four shear strength parameters linear regression methods

i.e. least square method

point center method

random-fuzzy method and reliability method

were carried out to conduct the comparison and theoretical analysis. An improved algorithm with rigorous solving process and higher calculation accuracy was proposed based on the traditional point center method. The optimized mean and standard deviation assignment method of shear strength parameters c

of rock mass discontinuities was presented to ensure the accuracy of initial assigned parameter with JC method based on reliability theory. An example of Jiweishan landslide in Wulong County was taken to explain the applicability of the above four methods under different data conditions of rock discontinuities. The result indicates that the applicability of four methods depends on the divergence and volume of the data. Each method of the four can be directly applied for the linear regression analysis of the shear strength parameters of rock discontinuities when the data is under good linear relationship. However

the point center method is not available anymore when the data is discrete; and the reasonable method should be determined according to the engineering requirements

exceptional value and convergence conditions.