基于PFC离散元的多层岩质陡坡危岩崩落序列研究

以三峡库区重庆万州青草背后山多层危岩边坡为研究对象，结合离散元仿真技术建立PFC3D颗粒流多层岩质陡坡危岩崩落的过程，并根据区域颗粒岩块位移、速度、荷载指标进行对比分析，分析了多层岩质陡坡危岩崩落序列规律及层间荷载变化规律。结果表明：该方法能合理呈现危岩陡坡的崩落规律，从曲线可以得到岩体峰值运动速度会随崩落时间逐渐衰减，崩落速度受力链断裂的影响较大，第1层力链影响速度峰值最大可达2.5m/s，下部危岩体对上部的回弹作用导致力链断裂速度由500st/p加快至167st/p。力链在每个崩落的峰值强度时刻都有明显的衰减，且随崩落时间推移衰减逐渐增大。该方法模拟的危岩崩落过程更加简便直观，为以后研究岩质陡坡危岩的破坏预测提供了重要手段。

Study on the collapse sequence of rocky steep slope dangerous rock based on particle discrete element

Taking the multi-dangerous rock slope behind the hills of Wanzhou Qingcao in the Three Gorges Reservoir area as the research object, combined with the process of PFC3D particle flow multi-layer rocky steep slope, and according to the regional particle rock displacement, velocity and load index, the comparative analysis is carried out. The sequence law of the collapse of dangerous rock in multi-layer rocky steep slope and the variation law of interlayer load are analyzed. The results show that the method can show the collapse law of steep slopes of dangerous rock. From the curve, the peak motion velocity of rock mass will gradually decrease with the collapse time. The collapse velocity is greatly affected by the force chain fracture. The first layer of the force chain affects the maximum velocity peak. Up to 2.5m/s, the rebound of the lower dangerous rock mass to the upper part causes the force chain breaking speed to increase from 500st/p to 167st/p. The force chain has a significant attenuation at the peak intensity of each collapse and gradually increases with the collapse time. The dangerous rock caving process simulated by this method is more simple, which provides a reference for predicting the damage of rocky steep slope dangerous rock in the future.