路基高陡石质边坡下柱式棚洞的应用与施工技术

Application of Columnar Hangar Tunnel Under Subgrade High Steep Rocky Slope and Its Construction Technology

富龙高速公路K15＋660-K15＋800段路线原设计以路堑形式通过,该地段为喀斯特地貌山区,地势险要,施工机械（挖机、钻机）难以进入坡顶,且上部开挖面较窄,设备无工作平台,难以进行施工作业。路堑边坡下方为进场道路和农田,峭壁石方爆破后无法控制落石走向。道路下方为部分旱地、水稻田和河道,爆破后滚落石渣对下部农田、河道破坏污染严重。K15处采用单幅柱式棚洞形式通过,减小了边坡的开挖高度,明显减少对山体的破坏,从而保护了山体上的植被。另外棚洞对高边坡除具有支挡作用,同时还具有公路隧道的功能,其结构与自然景观融为一体,不仅节约了投资,而且消除了高陡边坡顶部危岩、浮石危及公路安全,保证了公路建设与运营的安全。利用改装台车整体施工降低了施工难度,加快了施工速度,减小了施工中的安全风险。

Road cutting is designed as the original route of K15 ＋ 660 - K15 ＋ 800 section in Fulong Highway, the section is located in mountain area with rough and karst landform, the construction machinery （excavator, drilling machine） is difficult to reach the top of the mountain, and hard to operate due to narrow upper excavation and no working platform. Below the cutting slope are access roads and farmland, the falling rocks＇ track are unable to be controlled after the cliff rock blas- ting. Below the road are parts of dry land, rice fields and river channels, the rolling gravels after blasting will seriously damage and pollute the lower part of the farmland and river channels. Single columnar hangar tunnel is adopted at K15, which not only can decrease the slope excavation height but also significantly reduce the destruction to the mountain, thus protecting the vegetation on the mountain. In addition, hangar tunnel plays a role in supporting high slope, and it is also credited with the highway tunnel. The structure is integrated harmoniously with the natural landscape, it saves the invest- ment without threatening highway safety caused by dangerous rocks and pumice stones on top of the high steep slope, which ensures the highway construction and operation safety. The integral construction of the modified trolley can reduce the con- struction difficulty, speed up the construction schedule and cut down the safety risk in construction.