加固后泥石流拦挡坝结合面在滚石撞击下的动力分析

Dynamic Analysis of Rock-fall Impact on Adherence of Young on Old Concrete of Reinforced Debris Flow Dam

以泥石流重力式拦挡坝为原型,对加固后泥石流拦挡坝结合面在滚石撞击作用下的接触力、位移、损伤以及新旧坝体的能量进行对比研究,并利用ABAQUS有限元软件,模拟了在滚石不同撞击速度和撞击角度下加固后泥石流拦挡坝结合面的动力响应。结果表明:当滚石的撞击角度一定时,滚石的撞击速度越大,坝体结合面产生的位移越大,坝体结合面产生的接触力随着滚石撞击速度的增加而增加;当滚石的撞击速度一定时,滚石的撞击角度越小,坝体结合面上产生的位移越大,坝体结合面上产生的接触力随着滚石撞击角度增大而减小;在相同的滚石撞击角度下,滚石的撞击速度越大,坝体结合面混凝土损伤的速度越快;滚石的撞击能量一部分靠旧浆砌石坝体耗散,一部分靠新坝体来吸收,且这种作用在滚石高速撞击下尤为明显,滚石撞击速度越大,新坝产生的动能越大,且达到最大能量所需的时间越短,说明泥石流拦挡坝加固方案是有效的。

This paper takes debris flow gravity dam as prototype, compares and studies the adherence of young on old concrete of reinforced debris flow dam under the effect of rock-fall impact from the aspects including the contact force, displacement, damage, and the energy of the old and the new dam. The paper also simulates the dynamic responses of rock-fall impact on adherence of young on old concrete of reinforced debris flow dam under different impact velocities and incident angles by using ABAQUS finite element. The results show that when the incident angle remains unchanged, the greater the rock-fall speed is, the greater the displacement of adherence of young on old concrete is, and the contact force increases with the increase of impact speed;When the impact velocity is constant, the smaller the rock-fall incident angle is, the greater the displacement of adherence of young on old concrete is, and the contact force decreases with the incident angle. In the same impact angle, the greater the rock-fall speed is, the faster the damage speed of adherence of young on old concrete is. Part of the impact energy of rolling stones are dissipated on the old slurry masonry dam, and part of the energy is absorbed by the new dam. The adsorption effect is significant especial- ly under high speed of impact, the greater the rock-fall speed is, the more kinetic energy produced by the new dam, and also the shorter the time is required to reach the maximum energy. The results demonstrate that this reinforcement scheme is effective.