为解决“盾构法-矿山法”隧道对接施工中贯通方式的优选这一关键难题，比较盾构法和矿山法2种贯通方式的主要过程，并针对矿山法贯通方式提出盾构提前拆解概念；以围岩等级为变量，依次开展Ⅱ—Ⅴ级围岩条件下的盾构提前拆解施工过程数值计算，和以盾构提前拆解为前提的Ⅲ、Ⅳ级围岩中矿山法贯通施工过程数值计算。对比分析2种贯通方式的特点和各工况数值计算结果，得出结论如下： 1）提前拆机可有效提升盾构周转使用率，防止“卡机”和减小爆破冲击影响。2）比较盾构提前拆机过程计算结果，Ⅱ—Ⅳ围岩中塑性区发展和围岩变形均不明显，适合盾构提前拆机；Ⅴ级围岩中塑性区范围和变形均急剧增大，不适合盾构提前拆机。3）比较Ⅲ、Ⅳ级围岩矿山法贯通过程数值计算结果，Ⅳ级围岩中“盾构法-矿山法”隧道相接位置存在围岩变形突然释放现象，需要采取必要的加固措施。最后，根据上述结论制定了考虑围岩等级的“盾构法-矿山法”隧道对接贯通方式推荐表，并在实际工程中进行了应用。
It is essential to choose a suitable breakthrough mode
for the docking section between the shield and mined sections. The major
procedures of breakthrough mode by shield and mining methods are presented to
handle this issue, and the idea of shield dismantling before a breakthrough is
proposed for the docking section constructed using mining technique. The shielddismantling
process under the surrounding rocks of grades Ⅱ to Ⅴ and the breakthrough process using the mining method under the
surrounding rocks of grades Ⅲ and Ⅳ are simulated considering the surrounding rock grade as a variable.
By comparing the features of the two breakthrough modes and numerical
calculation findings, conclusions are drawn as follows: (1) The shield
dismantling before the breakthrough can efficiently enhance the turnover
utilization rate of the shield, avoiding machine jam and minimizing the impact
of blasting. (2) The numerical calculation results of shield dismantling in
advance reveal that the development of the plastic zone and deformation in
neighboring rocks of grades Ⅱ to Ⅳ are not clear, while that of grade Ⅴ increases rapidly, indicating that the shield dismantling in advance is
feasible in surrounding rocks of grades Ⅱ to Ⅳ and not feasible in surrounding rock of grade Ⅴ. (3) The numerical results of tunnel breakthrough by mining
technique in surrounding rocks of grades Ⅲ and Ⅳ indicate that the deformation rapidly increases at docking section
in surrounding rock of grade Ⅳ; thus, appropriate
reinforcement measures should be adopted. Finally, the breakthrough mode
selection method for docking section between shield and mined sections
considering surrounding rock grade are summarized and confirmed in practical
engineering.
