Calculation method for surrounding rock pressure in deep-buried four-hole closely spaced tunnel
With the continuous development of engineering construction, the number of tunnel excavation holes has increased. However, the theoretical framework for calculating the surrounding rock pressure in multi-hole tunnels remains imperfect. Focusing on four-hole closely spaced tunnels and based on Proto-dyakonov's theory, this study references existing load calculation models and incorporates the location characteristics of the four-hole tunnel. By simplifying the load calculation for deep-buried four-hole closely spaced tunnels, and considering the tunnel excavation sequence and the role of the middle rock pillar, a calculation method for surrounding rock pressure under deep burial conditions is proposed. Using this method, a four-hole highway tunnel in the city of Yuyao is calculated. The influence of the net distance between tunnels, tunnel excavation span, and the bearing capacity of the middle rock pillar on the surrounding rock pressure is analyzed. The results show that the net distance between tunnels affects the formation of additional bearing arches for tunnel surrounding rock pressure. The larger the net distance, the weaker the degree of bias pressure in each tunnel, and the changes in net distance between the two tunnels have a greater impact on the overall surrounding rock pressure. When the net distance between tunnels remains constant, increasing the excavation span of the tunnel gradually increases the surrounding rock pressure borne by the tunnel chamber, with the vertical pressure change on the inner side of the surrounding rock being higher than on the outer side. The stronger the bearing capacity of the surrounding rock, the lower the mutual influence of tunnel excavation under the same middle rock pillar thickness. This results in better distribution of the loose surrounding rock pressure from the additional balance arch above the tunnel, reducing the surrounding rock pressure borne by the tunnel support structure. The variation in the spacing between holes in a four-hole closely spaced tunnel significantly impacts the overall surrounding rock pressure, and the tunnel bias pressure characteristics gradually decrease with the increase in spacing.
four hole closely spaced tunnelrock pressuredeep-buried tunnelProtodyakonov's theory
万方数据
维普
