为研究降雨作用下河南省伊川县某滑坡的破坏运动特征分析,利用颗粒离散元软件,采用Ball-Wall法建立1:1数值计算模型并进行模拟计算,得出不同时间步长下的速度与位移云图,并在坡体不同的位置记录坡体运动过程中位移及速度变化的情况。研究结果表明:该滑坡整体破坏特征为:中部剪切–前缘牵引–后缘拉裂。表现为蠕滑–拉裂式破坏。前期坡体处于蠕滑阶段,坡体在位中前部位移速度最大,该位置率先破坏,其次为后缘部位,中前部与后缘因速度差挤压前方颗粒,随着时间推移,前缘部位颗粒开始剪出,后缘出现张拉裂缝,后续速度变化较为稳定,有整体下滑的趋势。In order to study the failure motion characteristics of a landslide in Yichuan County, Henan Province, under the action of rainfall, a 1:1 numerical calculation model was established by using the particle discrete element software and the Ball-Wall method and simulated. The velocity and displacement cloud patterns under different time steps were obtained, and the displacement and velocity changes during the movement of the slope were recorded at different positions of the slope. The research results show that the overall failure characteristics of the landslide are the middle shear-leading edge traction-trailing edge tensile cracking. The performance is a creep-tensile cracking failure. The slope is in the creep stage in the early stage, and the moving speed of the front part of the slope is the largest in the middle, which is the first to be destroyed, followed by the trailing edge. The front and rear parts of the slope are squeezed by the speed difference. As time goes by, the front edge particles begin to cut out, and tensile cracks appear on the trailing edge. The subsequent speed changes are relatively stable, and there is an overall downward trend.
甘肃省冬小麦相较其他品种小麦形态差异较大,针对其他品种小麦离散元仿真参数应用于甘肃省冬小麦播种机械设计与优化误差较大的问题,以‘甘农2号’种子为研究对象,采用物理试验测定种子本征参数及与PLA塑料、软胶和树脂间的静摩擦因数和碰撞恢复系数。基于离散元法(Discrete element method,DEM),利用EDEM软件结合斜面滚动试验,标定种子与PLA塑料、软胶和树脂间的滚动摩擦因数。采用圆筒提升法进行物理堆积试验,将试验所得堆积图像经MATLAB软件处理后得到种子物理堆积角,通过Design-Expert 8.06软件对多元二次方程进行多目标优化,获得种子颗粒间离散元模型接触参数较优组合,并利用EDEM软件进行验证。结果表明:小麦种子与PLA塑料、软胶和树脂的静摩擦因数分别为0.543、0.645和0.425;碰撞恢复系数分别为0.471、0.351和0.497;滚动摩擦因数分别为0.087、0.096和0.098。种子颗粒间静摩擦因数、碰撞恢复系数和滚动摩擦因数分别为0.43、0.50和0.07。物理堆积角为32.95°,仿真堆积角与物理堆积角相对误差为0.3%。本研究标定的冬小麦颗粒离散元仿真参数可为甘肃省小麦精量播种机械的设计优化提供参考。
