The Evaluation of Surrounding Rock Stability around Underground Engineerings Based on Improved Extension Evaluation Method

Combined with the research of the stability grade of surrounding rock, this paper put forward into the extension method on surrounding rock stability around underground engineerings with extension theory. The extension method was improved the value of the limited field, the correlation function and weights coefficients to establish the stability evaluation method. The method was successfully applied into the underground engineering case, which has provided scientific reference for design and construction of underground engineerings.