隧道洞口上方危岩崩塌块石运动规律及其对隧道的危害

为揭示危岩崩塌块石的运动规律及其对下方隧道洞口的危害,以都香高速昭通段乐红隧道洞口高陡边坡危岩区崩塌体为研究对象,运用理论计算与Rockfall数值计算2种形式对危岩区崩塌体失稳后块石的运动特征进行预测,运用Abaqus有限元软件模拟不同初速度、不同冲击落点下块石冲击隧道结构的动力响应,揭示不同因素对块石冲击隧道结构的影响程度.结果 显示:理论计算与Rockfall数值计算结果吻合,崩塌块石经坠落、碰撞、滚动最终会与隧道引洞段上表面发生碰撞;与冲击落点相比,块石初速度对隧道结构的动力响应特性影响更大;块石冲击落点位于隧道圆拱圆心正上方位置时对隧道结构的损伤最大;不同冲击落点对碰撞回弹后块石的速度影响不大.

Movement law of dangerous rock collapse block above tunnel entrance and its damage to tunnel

To study the movement law of dangerous rock collapse block and its damage to the tunnel portal below, taking the collapse block in the dangerous rock area of the high and steep slope above the entrance of Lehong tunnel in Zhaotong section of Duxiang expressway as the research object, two forms of theoretical calculation and Rockfall numerical calculation are used to predict the movement characteristics of rock collapse blocks after mass instability in dangerous rock area. The dynamic response of rock block impacting on tunnel structure with different initial velocities and impact points are simulated by Abaqus finite element software, and then the influence of different factors on the performance of rock block impacting on tunnel structure is revealed. The theoretical calculation results is consistent with the Rockfall numerical calculation results, and the collapse block will eventually collide with the upper surface of the tunnel approach section after falling, collision and rolling. Compared with the impact point, the initial volocity of rock block has a greater influence on the dynamic response characteristics of tunnel structure. While the impact point of collapse block is located directly above the center of the tunnel arch, the damage to the tunnel structure is the largest. The velocity of collapse block after impact rebound changes little with the different impact points.