关键词: 隧道式锚碇, 自重效应, 夹持效应, 承载力, 破坏形态

Abstract: Studies on the clamping effect and failure mode of the tunnel-type anchorage are still insufficient, leading to many difficulties in the optimization of design philosophy of the tunnel-type anchorage. In this work, the bearing characteristics, bearing mechanics and the failure mode of the tunnel-type anchorage were analyzed through 2D laboratory model tests. Besides, the influences of wedged angle and burial depth on the bearing capacity and failure mode were studied as well. This work reveals the essence of the clamping effect of the suspension bridge tunnel-type anchorage to some extent. Main conclusions are given as follow: First, additional stress is generated when the anchorage moves with a crescent accelerated velocity and squeezes the surrounding rock. The clamping effect results in resistance and the surrounding rock and soil start to bear the main cable load jointly. Second, the bearing capacity of the tunnel-type anchorage is contributed by gravity and the clamping effect. The clamping effect will play a role only when the gravity effect fails to balance the main cable load. From the view of economy and security, it is necessary to rationally design the size of the anchorage to ensure the role of the clamping effect. Third, the bearing capacity of the tunnel-type anchorage is also influenced by the wedged angle and it is necessary to optimize the wedged angle to obtain the maximum bearing capacity. Fourth, the bearing capacity of the tunnel-type anchorage increases linearly with the burial depth. Thus, in the actual project, the burial depth should be determined according to the bearing capacity, the construction difficulty, as well as economy. Finally, the initiation and propagation of the cracks is associated with the response of the stress and displacement. There is no crack initiation when the anchorage and surrounding rock are relatively static. The formation time of the failure mode corresponds to the nonlinear displacement stage of anchorage acceleration.

Key words: tunnel-type anchorage, gravity effect, clamping effect, bearing capacity, failure mode