Abstract: Adopting?the?FEM?numerical?simulation,?the?mechanical?characteristics?of?middle?rock?pillar,?the?approach?degree?of?surrounding?rock?yielding,the?bolt?axial?force?and?the?internal?force?of?secondary?lining?structure,?etc.?are?elaborated.?The?results?demonstrate?as?follows：?when?the?clear?distance?equals?B/3,?the?mechanical?behavior?of?middle?rock?pillar?is?adverse,?because?it?is?severely?affected?by?the?overlapping?effect?of?the?excavation?stress?field?from?left?and?right?holes;the?yielding?district?can?cut?across?middle?rock?pillar,?and?the?supporting-lining?structures?around?the?middle?rock?pillar?should?be?strengthened.?With?the?clear?distance?at?the?range?from?0.?85B?to?1.5B,the?mechanic?state?of?middle?rock?pillar?is?little?influenced?by?the?clear?distance.

Key words: neighborhood tunnel , construction mechanics , surrounding rock , supporting and lining structure , numerical simulation ;

摘要： 通过有限元数值模拟,分析了小净距公路隧道中夹岩柱的受力特性、围岩屈服接近度、锚杆轴力、二次衬砌混 凝土内力特征等。研究结果表明:净距较小为B/3时,研究区中夹岩柱围岩会受到左右双洞开挖应力场重叠作用 的严重影响,受力状态十分不利,屈服区也贯通中夹岩柱,中夹岩柱两侧的隧道支护衬砌结构都应有所加强;当净 距为(0??85~1??5)B时,中夹岩柱受力状态受净距的影响已很小。

关键词: 小净距隧道, 施工力学, 围岩, 支护衬砌结构, 数值模拟