Abstract:In order to study the calculation method of surrounding rock pressure of large diameter shaft in highway tunnel, based on the limit equilibrium method derivation, and compared with the measured data of Guantian shaft, the influence of shaft diameter, lateral pressure coefficient, and surrounding rock grade on the surrounding rock pressure of shaft was analyzed. The results show that: 1) Compared with the measured data, the average error of the formula in this article is within 12.85, while the error of other formulas is above 180, reducing the relative error by more than 167.15. This can guide engineering personnel in the construction design of vertical shafts. 2) The larger the excavation diameter of the shaft, the greater the surrounding rock pressure on the shaft wall, but the increase in surrounding rock pressure gradually weakens as the diameter increases. 3) Before reaching the limit depth, the greater the lateral pressure coefficient, the greater the surrounding rock pressure of the shaft wall; After reaching the limit depth, the surrounding rock pressure of the shaft wall is the same under different side pressure coefficient. The greater the lateral pressure coefficient is, the greater the wall rock pressure increases with the shaft depth, and the faster it reaches the maximum wall rock pressure, that is, the smaller the limit depth. 4) The higher the level of surrounding rock, the lower the pressure of the surrounding rock on the shaft wall, and the lower the pressure of the surrounding rock after reaching the limit depth.