Abstract: According?to?the?monitoring?data?of?the?large-section?tunnel?of?one?3-lane?expressway?in?Yunnan?province,?the?mechanical?characteristics?of?composite?lining?structure?at?each?construction?stage?have?been?studied,?mainly?including?bolt?axial?force,?ground?pressure,?internal?force?of?steel?arch?shelf,?secondary?lining?structure?load?state?and?so?on.?The?results?demonstrate?that：?mechanical?situation?of?composite?lining?structure?is?very?complex,?and?unsymmetrical?pressure?always?exists?because?of?V-grade?surrounding?rock?structure?difference.?The?actual?ground?pressure?is?far?smaller?than?theoretical?value?of?that,?so?some?supporting?structural?parameters?of?the?pre-design?may?be?adjusted?properly.

Key words: large-section highway tunnel , composite lining , monitoring , unsymmetrical pressure ;

摘要： 以云南昆石高速公路某3车道大断面隧道为实例,对其典型断面洞室复合式衬砌结构各施工阶段的受力特 性进行跟踪监测,详细分析了锚杆轴力、围岩压力、钢拱架内力、二次衬砌混凝土结构的受力状况,研究结果表明: 受围岩体结构不均匀性的影响,其??级围岩复合式衬砌结构的总体受力状况较为复杂,存在着一定的偏压现象,实 测围岩压力远小于理论计算值,原施工图预设计的部分支护结构参数可以再作适当的优化调整。

关键词: 大断面公路隧道, 复合式衬砌, 监测, 偏压