基于PFC3D的圆盘锯切割破岩机理及影响因素研究

Research on Mechanism and Influencing Factors of Circular Saw Cutting Rock Based on PFC3D

圆盘锯切割边坡开挖质量高,对边坡岩体扰动小,边坡稳定性高,但到目前为止,边坡切割开挖参数的选择主要依据操作人员的经验确定,制约了该技术的广泛应用。基于圆盘锯切割破岩的力学机制,采用PFC3D离散单元模型,对圆盘锯切割破岩的细观机理进行研究,对影响切割边坡稳定性的关键因素进行分析。结果表明:锯片给进速度、切割深度与边坡岩体的损伤程度呈正相关关系,给进速度和切割深度越大,产生的裂隙数目越多,对边坡岩体的损伤越大;多次切割和一次切割同样深度锯片受力情况相差不大,但多次切割比一次切割在岩石中产生的裂隙数目和裂隙范围更小,即多次切割对岩体损伤更小;旋转速度和方向对破岩效果影响不大。研究成果可以为岩质边坡圆盘锯切割开挖提供参考和依据。

The circular saw cutting slope has requirements on high excavation quality,little disturbance to slope rock mass and high slope stability.But the selection of slope cutting and excavation parameters is mainly based on the experience of operators so far,which restricts the application of the technology.Based on the mechanical mechanism of circular saw cutting and breaking rock,this paper adopts PFC3D discrete element model to study the meso-mechanism of circular saw cutting and breaking rock,then it analyzes the key factors affecting the stability of slope.The results show that the forward speed and cutting depth of the saw blade are positively correlated with the damage degree of the slope rock mass.The larger the forward speed and cutting depth are,the more cracks are produced and the greater the damage to the slope rock mass is.There is little difference in the force of the saw blade between multiple cutting and single cutting at the same depth,but the number and range of cracks produced by multiple cutting are smaller than that of single cutting,that is,the damage to rock mass is smaller by multiple cutting.Rotation speed and direction have little influence on rock breaking effect.The research results could provide reference and basis for cutting and excavation of rock slope with circular saw.