隧道可拆构件式临时仰拱技术及应用研究

Technology and Application of Temporary Invert With Detachable Components in Tunnels

为解决传统工字钢+喷射混凝土临时仰拱施工工序复杂、施作质量受人为因素影响大、无法循环利用的难题,依托实际工程,提出一种新型可拆构件式钢管混凝土临时仰拱及其配套快拆结构,并在同塞高速总卡2#隧道开展测试应用。临时仰拱钢管外径108 mm,壁厚8 mm,管内填充C30细石混凝土;快拆结构由套筒和内置楔形卸荷块组成,钢管混凝土从两侧插入,实现节段连接。现场应用结果表明:1)该可拆构件式钢管混凝土临时仰拱结构安全可靠、工艺可行,可实现工厂预制加工及现场快速拆装,较传统工字钢+喷射混凝土临时仰拱工效提高64.3%,拱顶沉降变形速率降低65.7%~66.1%,周边收敛速率降低74.6%~79.5%;2)结构运行期间实测轴力值小于计算值和设计值,结构处于安全状态,节段重复利用率达94.5%,快拆结构重复利用率达100%。

The traditional temporary invert constructed by I-steel+shotcrete is complex in the construction process.Moreover,its construction quality is greatly affected by human factors and cannot be reused.Therefore,a novel detachable concrete-filled steel tube temporary invert and its supporting structure,designed for easy and rapid disassembly,are proposed.The structures are tested and applied to the high-speed Zongka#2 tunnel of the Tongren-Sai′erlong railway.The steel pipe has an outer diameter of 108 mm and a wall thickness of 8 mm,and is filled with C30 fine stone concrete.The detachable components comprise a sleeve and a built-in wedge-shaped unloading block,and the concrete-filled steel tubes are inserted from both sides to achieve segment connection.Field application results reveal the following:(1)The proposed temporary invert structure is safe,reliable,and feasible and can realize factory prefabrication and quick disassembly on site.The proposed temporary invert can improve construction efficiency by 64.3%and reduce the settlement deformation rate of the arch and peripheral convergence rate by 65.7%~66.1%and 74.6%~79.5%,respectively,compared to the traditional temporary invert constructed by I-steel+shotcrete.(2)The axial force value measured during the operation of the structure is less than the calculated and designed ones,indicating that the structure is in a safe state.The reutilization rates of the segment and detachable structure are up to 94.5%and 100%,respectively.