小净距隧道在不同开挖方式下的力学效应分析

结合某公路隧道出口端隧道间距较小的实际情况，运用数值计算的方法，对软岩条件下小净距隧道在不同开挖方式下达到稳定后围岩和复合衬砌的力学效应进行了分析，同时，考察不同净距对中夹岩墙塑性区的影响。结果表明：施工小净距隧道应慎重选择后继施工隧道的开挖方式；后继隧道施工的开挖方式直接对先行既有隧道锚杆、喷射混凝土和二次衬砌应力状态产生很大影响；中夹岩墙塑性区大小与净距紧密相关，同时，隧道埋深和围岩类别也是影响塑性区大小的重要因素。

#Study on Mechanics Effect of Small -distance Tunnels Located at Soft Ground

Mechanics effect of ground and composite lining is taken aa study object after small - distance tunnels which are located at soft ground achieves stability under different excavation methods, and analysis is focused on mechanics characteristics of bolt, shotcrete, secondary lining, also the plastic zone influence of middle rock wall with different interval. The result shows that the excavation method of subsequence construction tunnel should be chosen carefully, and the excavation method of subsequence construction tunnel has direct great influence on stress state of bolt, shotcrete, secondary lining of former tunnel. The size of interval is the most important factor which influences magnitude of the plastic zone, and covering depth and classification of rock mass are also important factors.