隧道-滑坡平行体系时间效应演化及变形破坏试验研究∗

通过4组隧道-滑坡平行体系模型试验,研究在不同工况下隧道-滑坡相互作用下的时间效应和变形破坏模式。结果表明:(1)隧道-滑坡平行体系单滑面情况滑坡推力在滑体内产生一种应力临界状态,该应力临界状态是处于拉、压应力变化过渡的一种状态,有一个时间传递变化的过程,即时间效应。(2)桥隧搭接桩基础支撑结构较无支撑结构会加速应力临界过渡状态的时间效应。(3)滑坡体内的滑坡推力,最先引起滑带位置附近的土体达到应力临界过渡状态,随着时间的推移,这种临界状态逐步由滑坡体后缘向前缘移动,滑坡破坏面上的每一点的时间与应变关系均会呈现不同的"S"型曲线特征,对于整个滑体而言,滑面上每一点的时间与应变关系曲线,在不同时刻呈现不同的线型特征。(4)桥隧搭接桩基础支撑结构较无支撑结构会延缓隧道模型的破坏,使得破坏断裂面向基岩内部延伸,且作用效果显著,但隧道模型整体的破坏处于基岩内。

Experimental Study on Time Effect Evolution and Deformation and Failure of Tunnel-slide Parallel System

In this paper, four tunnel-landslide parallel system model tests are conducted to study the time effect and deformation failure mode considering the interaction between tunnel and landslide under different conditions. The results show that: (1) Landslide thrust in parallel system of tunnel-landslide produces a critical state of stress in the sliding body. This critical state is in a transitional state of tension and compression stresses, with a time-varying process, that is, the time effect. (2) The bridge-connected pile foundation supporting structure can accelerate the time effect of critical stress-transient state, compared to the unsupported structure. (3) The landslide thrust in the landslide body firstly leads the soil near the sliding zone to reach the critical transitional state of stress; this critical state gradually moves from the trailing edge of the landslide body to the front edge. The relationship between the time and strain of each point will show different "S"-shaped curve characteristics. For the entire sliding body, the curve of time and strain at each point on the sliding surface presents different linear features at different moments. (4) Compared with the unsupported structure, the bridge-connected pile foundation supporting structure will delay the destruction of the tunnel model, so that the failure fracture extends toward the interior of the bedrock and the effect is remarkable. However, the overall damage of the tunnel model is within the bedrock.