隧道软岩洞口段纤维混凝土衬砌抗震性能研究

为了进一步提高强震区隧道软岩洞口段的震时安全性,依托白云顶隧道进口段工程,对采用钢纤维混凝土二衬、玄武岩纤维混凝土二衬和钢筋混凝土二衬的隧道软岩洞口段进行了大型振动台动力模型试验。试验结果表明:采用纤维混凝土二衬提高了支护结构的强度及韧性,可有效提高隧道结构的震时安全性;硬岩段隧道结构安全性由运动相互作用控制,采用纤维混凝土二衬,隧道结构所承受的地震惯性力变化很小,安全系数最小值提高较大,最高增长了71.07%;软岩段隧道结构安全性由运动相互作用和地震惯性相互作用共同控制,采用纤维混凝土二衬对于抵抗隧道结构所承受的地震惯性力作用明显,安全系数最小值最高增长了30.40%。该研究成果可为强震区软岩洞口段的抗震设防设计提供参考。

Shaking Table Model Test for Aseismatic Performance of Fiber-Reinforced Concrete Lining of Tunnel Portal Section in Soft Rock

In order to further improve the earthquake safety of the tunnel portal section in soft rock of meizoseismal area, large-scale shaking table model tests are carried out for the tunnel portal section in soft rock with the secondary lining of steel fiber reinforced concrete, the secondary lining of basalt fiber-reinforced concrete and the secondary lining of reinforced concrete, relying on the tunnel engineering of Baiyunding tunnel portal section.. The experimental results show that the strength and toughness of the supporting structure are improved by using the secondary lining of fiber reinforced concrete, which can effectively improve the safety of the tunnel structure in earthquake. The safety of the tunnel structure in hard rock is controlled by the kinematic interaction. The change of the earthquake inertia force in the tunnel structure bears is very small, and the minimum safety factor greatly increases up to 71.07%, by using the fiber reinforced concrete secondary lining. Furthermore, the safety of the tunnel structure in soft rock is controlled by both the kinematic interaction and the seismic inertia interaction. It is obvious for the tunnel structure to resist its earthquake inertia force, and the minimum safety factor increases by 30.40%, with the fiber reinforced concrete secondary lining. The results can provide references for anti-seismic and fortification design of tunnel portal section in soft rock of meizoseismal area.