双幅棚洞防护路基高边坡施工技术

Construction Technology of Subgrade High Side Slope with Double Amplitude Shed Hole Protection

山区高速公路受地形限制,路线常在崇山峻岭中傍山而行,路基边坡地质复杂且高陡,开挖后极易失稳滑坍,且处置难度较大,加固后的边坡易再次发生失稳滑坍,对高速公路运营造成极大的安全隐患。云南省富龙高速公路K14处高边坡开挖后发生4次滑坍,经方案比选后采用双幅棚洞防护通过,节约了滑坍边坡的处置成本,消除了高陡边坡再次滑坍的隐患,保证了山区公路的运营安全。使用2部经合理改装后的隧道用衬砌台车同时施工左右幅棚洞洞身、中墙及中墙顶混凝土,提高了洞身的结构整体受力情况,减少了施工缝对洞身防排水质量的影响,降低了施工难度,加快了施工进度,可为今后类似路基防护施工提供借鉴。

Being restricted by the terrain, the routes of highway in mountainous areas are built along the mountains. The subgrade slope is high and steep, with complicated geology conditions, so it is very easy to be resulted in instability and sliding failure after excavation. The disposal is relatively difficult due to the reinforced slope is easy to cause instability and sliding failure again. Therefore, it will bring a great security risk to the highway operation. There are four sliding failures in the position of K14 high slope of Fulong Highway in Yunnan after excavation, the method of double amplitude shed hole protection is adopted after scheme comparison. It saves the repair cost of sliding slope, eliminates the hidden danger on secondary sliding of high and steep slope, and ensures the operation safety of highway in mountainous areas. Using two lining trolleys after reasonable modification to simultaneously construct the concrete of the double amplitude shed hole in the forms of the body, the middle wall, and top of the middle wall, it improves the whole stress distribution of the tunnel, reduces the influence of construction joints on the quality of waterproof and drainage of the tunnel, cuts down the construction difficulty and speeds up the construction progress. It can provide a reference for similar subgrade protection construction.