基于离散元法的砂砾石颗粒破碎特征研究

STUDY ON THE PARTICLE BREAKAGE CHARACTERISTICS OF SAND GRAVEL BASED ON DISCRETE ELEMENT METHOD

为从微观角度研究砂砾石土的土体变形特性。文中用离散元法对砂砾石单颗粒不同接触状态下的破碎特征进行二维和三维数值模拟,得到了砂砾石单颗粒在单点、两点及三点接触状态下的破碎特征。结果表明颗粒的临界破碎压力与粒径密切相关,随着颗粒粒径的增大,所需的临界破碎压力也越大,临界破碎压力F与颗粒粒径R之间呈近似线性关系;颗粒的临界破碎压力与支撑角也有密切的关系,当支撑角≤55°时,支撑球对颗粒有明显的固定作用,颗粒的临界压力小幅增加;当支撑角>55°时,颗粒极易破碎,当支撑角为75°时,临界破碎压力仅为最大临界破碎力的20%。研究成果可为建立考虑颗粒破碎的砂砾石粗粒土本构模型提供一定的理论支持。

This paper studies the soil deformation characteristics of sandy pebble soil within the microscopic scale.The discrete element method is used to simulate the fracture characteristics of single sand and pebble particles un⁃der different contact states,from which the fracture characteristics of single sand and pebble particles under single point,two point and three-point contact states are obtained.The results show that the critical crushing pressure of the particles is closely related to the particle size.With the increase of the particle size,the required critical crush⁃ing pressure is also larger,and the critical crushing pressure F is approximately linear with the particle size R.The critical crushing pressure of particles is also closely related to the supporting angle.When the supporting angle is≤55°,the supporting ball has obvious fixing effect on particles,and the critical pressure of particles increases slightly.When the support angle is>55°,the particles are easily broken;when the support angle is 75°,the critical crushing pressure is only 20%of the maximum critical crushing force.The results may provide the theoretical support for the establishment of coarse-grained soil constitutive model considering particle breakage.