双连拱公路隧道支护结构体系试验研究

Experiments of Support Structure of Twin-Bore Highway Tunnels

为了确定Ⅱ类围岩条件下四车道双连拱公路隧道的合理支护结构和支护原则,进行了相似模拟试验,并通过现场原位试验进行印证和补充.结果表明:中墙内力在施工过程中变化十分复杂,施工中应重点考虑中墙抗倾覆的要求;初期支护体系应以系统锚杆和喷混凝土为主、钢支撑为辅.最后提出了在Ⅱ类及以下围岩中修建四车道双连拱公路隧道的施作原则.

Similar simulation tests were made to determine the reasonable structure and principle of supporting for twin-bore highway tunnels with four driveways excavated in class Ⅱ surrounding rock, and in-situ testing was carried out to prove and complement the experimental result in laboratory. The research results show that because stresses in the mid-partition of twin-bore highway tunnels become very complexly in the construction process, main attention shall be paid to preventing the mid-partition from turning over during the construction. In addition, rock bolts and shotcrete, instead of steel supports, should be taken as the main preliminary supporting of twin-bore highway tunnels with four driveways excavated in classⅡsurrounding rock. Finally, the principle of supporting was put forward for twin-bore highway tunnels with four driveways excavated in classes Ⅰ and Ⅱ surrounding rocks.