Abstract
Extremely broken phyllite is widely distributed and is easily seen in engineering construction. Aiming at the problem that the empirical strength parameters of extremely broken surrounding rock have intense subjectivity and significant difference, based on the characteristics of the existence of particle group state in the highly broken surrounding rock, the fractal theory and large‐scale direct shear test are used, the fractal description of polar broken phyllite samples with different pile numbers in fault fracture zone of Qinyu Tunnel is carried out, and the fractal dimensions and empirical strength parameters of each sample are determined. Based on a fractal description and large shear test, the functional relationship between fractal dimension and empirical strength parameter of extremely broken phyllite in fault fracture zone is established, and the quantitative value method of empirical strength parameter determined by fractal dimension of extremely broken phyllite is given, which provides ideas for the quantitative value of empirical strength parameter of the similar extremely broken surrounding rock.
Highlights
Rock mass strength criterion is the basis for judging whether it is damaged in theory and an important basis for engineering design
The accuracy of relevant empirical parameters in the strength criterion is the most important factor to determine whether the rock mass strength criterion is reasonable. erefore, in engineering design practice, reasonably and accurately determining the relevant empirical parameters of rock mass strength criterion is the basis of its wide application. e Hoek–Brown strength criterion is a combination of rock theoretical research results and many test results statistics
Its simplicity and practicability have been widely accepted by the engineering geological circles. It is the most widely used and influential rock strength criterion so far, and it is a method recommended by the international society of rock mechanics [1,2,3,4]. e envelope of the Hoek–Brown strength criterion is parabola, which can describe the nonlinear failure characteristics of rock mass. e essence of the strength criterion is to attribute all factors affecting the strength characteristics of rock mass to two empirical strength parameters m and s, so the value of empirical parameters m and s of rock mass will play a decisive role in the accuracy of the strength criterion [5, 6]
Summary
Rock mass strength criterion is the basis for judging whether it is damaged in theory and an important basis for engineering design. Erefore, in engineering design practice, reasonably and accurately determining the relevant empirical parameters of rock mass strength criterion is the basis of its wide application. Its simplicity and practicability have been widely accepted by the engineering geological circles It is the most widely used and influential rock strength criterion so far, and it is a method recommended by the international society of rock mechanics [1,2,3,4]. Field estimation is a method to establish a quantitative relationship between rock mass quality evaluation index and empirical parameters by comprehensively considering many factors affecting rock mass strength. The RMR rock mass scoring system is not suitable for broken rock mass, so GSI geological strength index is the most widely used empirical strength parameter value method [15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
