深埋隧道台阶法施工围岩压力拱的变化规律
Regulation of Pressure Arch around Deep Buried Tunnel during Construction with Steps Method

通过分析隧道台阶法施工过程中围岩应力重分布的规律，研究压力拱的动态变化，得出：两台阶法临时和最终上部压力拱的厚度均较相应侧压力拱大，但坐标轴上最大应力相对增量均相应较小；两台阶法临时上部压力拱向隧道壁移动而临时侧压力拱远离隧道壁移动形成相应最终压力拱，而最终压力拱厚度和坐标轴上最大应力均较大；两台阶法中随上台阶高度的增大，临时上部压力拱逐渐向隧道壁移动并趋于稳定，而临时侧压力拱逐渐远离隧道壁并趋于稳定，临时压力拱厚度均先增大后趋于稳定，坐标轴上最大应力均逐渐增大；台阶数量不影响最终压力拱。
Through analysis of stress redistribution of surrounding rock during the tunnel construction process step, the dynamic changes of tunnel pressure arch were studied. The conclusions were gotten: in the two process steps the thickness of the temporary and final upper pressure arch is larger than that of the side pressure arch, but the maximum stress on the coordinate axis is relatively smaller, the temporary upper pressure arch moves to the tunnel and the temporary side pressure arch moves away from the tunnel to form the corresponding final pressure arch, and the final pressure arch thickness and the maximum stress on the coordinate axis are larger, with the increase of the height of the upper step, the temporary upper pressure arch gradually moves away from tunnel and stabilized, the temporary side pressure arch gradually moves away from the tunnel and stabilized, the thickness of temporary pressure arch is increased and then stabilized, the maximum stress on the coordinate axis increases; the step quantities do not affect the final pressure arch.