超前预支护技术在穿河隧道施工中的应用

Application of forepoling in construction of under-river tunnel

长沙市湘江大道浏阳河隧道下穿浏阳河,水下暗挖隧道K1+020—K1+110段,覆土厚度最薄处仅14 m,该隧道具有小净距、强风化、浅埋、水下暗挖的特点。以长沙市湘江大道浏阳河隧道暗挖段施工为例,介绍了该工程所采用的长短管棚和小导管相结合的超前支护、玻璃纤维锚杆超前加固、地面垂直注浆和全断面超前帷幕预注浆等复杂地质条件下暗挖段超前综合加固支护施工技术,有效地保障了暗挖段的施工质量和安全。

Liuyang river tunnel on changsha xiangjiang road is under-crossing the liuyang river, the thinnest thickness of covering soil is only 14 m on K1 ＋ 020--K1 ＋ 110 section in underwater tunnel which has the characteristics of small clear distance, strongly weathering, shallow, underwater subsurface excavation. Taking liuyang river tunnel construction of underground section on changsha xiangjiang road as an example, this paper introduced integrative advanced reinforce support technology of underground section under complex geological conditions, such as the advanced support of combing long-short pipe shed with small pipe, glass fiber advanced reinforce, ground vertical advanced bolt grouting and wholesection advanced grouting, etc., which effectively guarantee construction quality and safety of the underground section.