General Formulas for Calculating Surrounding Rock Pressure of Tunnels and Underground Spaces

Abstract

Through the analysis of the statistical data from a large number of existing tunnels and underground space engineering projects, the limitations of the commonly used formulas for calculating the surrounding rock pressure of tunnels are examined, and the calculated values were compared with the measured values to reveal the differences between them. A model and research approaches that differ from those associated with the commonly used formulas at present are proposed, a calculation method that takes into account multiple objective factors affecting the surrounding rock pressure established, and a general formula for calculating the surrounding rock pressure derived for convenient engineering application. Various factors that influence the surrounding rock pressure are discussed. The values calculated per various commonly used formulas, the values calculated per derived formulas, and the measured values are compared in terms of relative errors. The general formula is then used to extract a general formula for dividing the deep and shallow burial cases, a general formula for calculating the surrounding rock pressure of deep buried tunnels, and a simplified formula for calculating the surrounding rock pressure of tunnels with different shapes. This study shows that the values calculated per general surrounding rock pressure formula are very close to the measured values, as demonstrated by the high correlation coefficient and the average error being within a reasonable range, thus verifying the reliability and applicability of the formula. The results can provide useful guidance and reference for the design and construction of tunnels and underground spaces.