A gravel cushion is an effective method for preventing rockfall disasters, but the thickness and particle size of cushion influence the impact response between rockfall and cushion. Based on previous indoor experiments, a numerical model of a rockfall impacting a cushion was built, and the accuracy of the model were verified by comparing with the coefficient of restitution obtained from experimental results. Then, the impact response characteristics during collision between rockfall and cushion, including the impact force on the cushion surface, the impact force on the cushion bottom, and the penetration depth, were studied. It was found that decreasing the cushion thickness can only reduce the impact force on the cushion bottom, while decreasing the particle size of the cushion can reduce both the impact forces on the cushion surface and bottom. With an increase in the falling height of rockfall, both of the impact forces on the cushion surface and bottom consistently increase, and the increase rate of the impact force on the cushion surface is higher than that of the impact force on the cushion bottom. The penetration depth is significantly affected by the particle size of cushion. With an increase in the falling height of rockfall, the penetration depth increases, but when the particle size of cushion is relatively large, the influence of the falling height of rockfall on the penetration depth decreases to some extent. These numerical results provide a widely applicable theoretical foundation for gravel cushions against rockfall disasters.

砾石垫层是预防落石灾害的有效方法，但是垫层的厚度和粒径会影响落石和垫层之间的冲击响应。在以前的室内实验基础上，建立了落石冲击垫层的数值模型，并与实验结果得到的恢复系数进行了比较，验证了模型的准确性。然后，研究了落石与垫层碰撞过程中的冲击响应特性，包括对垫层表面的冲击力，对垫层底部的冲击力以及穿透深度。已经发现，减小垫子的厚度只能减小对垫子底部的冲击力，而减小垫子的粒度可以减小对垫子表面和底部的冲击力。随着落石下落高度的增加，在垫子表面和底部上的冲击力都持续增加，并且在垫子表面上的冲击力的增加率高于在垫子底部上的冲击力的增加率。渗透深度受垫子粒径的影响很大。随着落石下落高度的增加，穿透深度增加，但是当垫层的粒径较大时，落石下落高度对穿透深度的影响在某种程度上减小了。这些数值结果为砾石垫层抗落石灾害提供了广泛适用的理论基础。并且，在垫子表面上的冲击力的增加率高于在垫子底部上的冲击力的增加率。渗透深度受垫子粒径的影响很大。随着落石下落高度的增加，穿透深度增加，但是当垫层的粒径较大时，落石下落高度对穿透深度的影响在某种程度上减小了。这些数值结果为砾石垫层抗落石灾害提供了广泛适用的理论基础。并且，在垫子表面上的冲击力的增加率高于在垫子底部上的冲击力的增加率。渗透深度受垫子粒径的影响很大。随着落石下落高度的增加，穿透深度增加，但是当垫层的粒径较大时，落石下落高度对穿透深度的影响在某种程度上减小了。这些数值结果为砾石垫层抗落石灾害提供了广泛适用的理论基础。但是当垫层的粒径较大时，落石落落高度对穿透深度的影响会有所减小。这些数值结果为砾石垫层抗落石灾害提供了广泛适用的理论基础。但是当垫层的粒径较大时，落石落落高度对穿透深度的影响会有所减小。这些数值结果为砾石垫层抗落石灾害提供了广泛适用的理论基础。