落石冲击荷载作用下加筋土拦石墙冲击应力分布研究

Study on impact stress distribution of ground reinforced embankments under rockfall impact

为研究加筋土拦石墙在落石冲击荷载下的冲击应力分布规律,设计加筋土拦石墙和板桩拦石墙落石冲击模型试验。通过对比试验揭示了加筋土拦石墙在落石冲击荷载作用下冲击应力峰值的变化规律。试验发现:(1) 2种结构的冲击应力分布均呈阶段性变化,加筋土拦石墙裂隙出现时所承受的冲击力约为板桩拦石墙的2倍;(2)与板桩拦石墙冲击处应力集中明显相比,加筋土拦石墙冲击处应力分布均匀,墙面变形较小,应力消散速率较板桩拦石墙小约50%。结合修正的Hertz接触冲击力计算公式和Boussinesq方程,得到加筋土拦石墙内部冲击应力计算方法。通过试验和理论对比发现,加筋土拦石墙在落石冲击下应力分布和抗冲击性能均优于板桩拦石墙。研究成果可为加筋土结构在冲击荷载作用下的性能研究和工程应用提供理论依据。

In order to study the impact stress distribution law of ground reinforced embankments under falling rock impact,the model tests of ground reinforced embankments and pile-plate retaining walls under the impact of a rock block were designed. The comparison tests reveal the change law of the peak impact stress of ground reinforced embankments under the impact of rockfall. The test results show that the impact stress distributions of the ground reinforced embankment and the pile-plate retaining wall change in stages,while the impact force of ground reinforced embankment when cracks appear is about twice that of the pile-plate retaining wall. Compared with the obvious stress concentration near the impact point of the pile-plate retaining wall,the stress distribution of the ground reinforced embankment is uniform,the deformation of the wall is small,and the stress dissipation rate is about 50% smaller. Combined with the modified Hertz contact impact force calculation formula and Boussinesq equation,an internal impact stress calculation method of ground reinforced embankments is obtained.Through experimental and theoretical comparisons,it is found that the stress distribution and the impact resistance of the ground reinforced embankment under rockfall impact are better than those of the pile-plate retaining wall.The research results can provide theoretical basis for the performance research and engineering application of reinforced soil structures under impact loads.