中文摘要：

连拱隧道一般用于中、短隧道和隧道接线部位，除在隧道的进山、出山口遭遇仰坡和侧向边坡外，隧道主体也常处于边坡地形之中，需要对边坡的稳定性进行分析论证。连拱隧道开挖断面大，多次开挖支护以及应力的平衡、转换可能对边坡的稳定性产生显著影响，在极端不利情况下，甚至可能诱发滑坡。连拱隧道主体与边坡相互作用模式可概括为4种：隧道位于滑面以下；隧道穿越滑面；隧道位于滑面以上的坡顶；隧道位于滑面以上的坡脚，可采用修正的不平衡推力传递法分析其稳定性。对于边坡滑面不能预先判定情况，可采用数值计算方法，分析隧道开挖工法对边坡稳定性的影响。按强度折减法分析，在三导洞工法中先开挖远山侧更有利于边坡的稳定。

英文摘要：

Twin-arc structure is usually used for connection tunnels and tunnels of short to medium lengths, and the main structure is often constructed in a slope, in addition to front and side slopes nearby tunnel portal. The excavation section is large, and the construction procedure is complicated, which causes the surrounding rock disturbed several times and thus significantly affect the stability of tunnel slope. Under extreme adverse conditions, landslide may be triggered. The modes of interaction between a twin-arc tunnel and slope include ： （ 1 ） tunnel is located far below from potential landslide surface; （2）tunnel goes across the potential landslide surface, （3）tunnel is located far above from potential landslide surface and close to top of slope; and（4）tunnel is located far above from potential landslide surface and close to slope base. When the potential landslide surface can be determined and tunnel goes across it, a modified method of stability analysis is developed to evaluate the influence of tunnel construction to slope, whereas if landslide surface cannot be determined in advance, numerical method is employed. Calculation results indicate that the construction of a twin arc tunnel will significantly affect the stability of slope, and for 3-pilot construction method, excavating the pilot tunnel farfrom the mountain first is more advantageous.