AUTHOR=Ji Zigang , Li Jinhang , Zhang Xuehui , Song Zhanping 

TITLE=A quantitative assessment method for the correlation between rock mass basic quality and Protodyakonov coefficient

JOURNAL=Frontiers in Earth Science

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2023.1249866

DOI=10.3389/feart.2023.1249866

ISSN=2296-6463

ABSTRACT=<p>With the implementation of the “Belt and Road” initiative, tunnel projects were designed in accordance with Russian design specifications and constructed by Chinese companies in countries along the route. Design companies and construction companies use different rock classification methods, which will increase the safety risk and cost of the tunnels. Therefore, it is necessary to study the correlation between Chinese engineering rock mass classification and Russian rock mass classification. The goal was to establish the correlation between rock mass basic quality (<italic>BQ</italic>) and Protodyakonov coefficient (<italic>f</italic>) for rock mass classification. Firstly, based on the equivalence principle of uniaxial compressive strength (<italic>UCS</italic>), the relationship between <italic>BQ</italic> and <italic>f</italic> containing the velocity index of rock mass (<italic>K</italic><sub><italic>v</italic></sub>) was established by comparing the relationship between <italic>f</italic> and <italic>BQ</italic> in the empirical formula of <italic>UCS</italic>. Secondly, through the equivalent principle of volumetric joint count of rock mass (<italic>J</italic><sub><italic>v</italic></sub>), we compared the empirical formula between the intactness index of <italic>K</italic><sub><italic>v</italic></sub> and rock quality designation (<italic>RQD</italic>) and conducted linear regression analysis on a large amount of data. The relationship between <italic>K</italic><sub><italic>v</italic></sub> and <italic>RQD</italic> was established. Finally, the relationship between <italic>BQ</italic> and <italic>f</italic> is quantitatively expressed and a classification table corresponding to the Russian rock classification and the Chinese engineering rock classification is obtained. The method is applied to Kyrgyzstan mountain tunnels.</p>