二维方形骨料随机投放特性

Characteristics of two-dimensional square aggregate random delivery

文章以有限元数值模拟为研究手段,通过Matlab编程模拟沥青混凝土数值试件骨料的随机投放过程,将2.26mm及以下的骨料与沥青共同视为沥青砂浆,通过室内压缩试验确定材料参数;对骨料随机投放后的数值试件进行网格划分,把骨料和沥青砂浆按单元集合归类,赋予各集合相应材料参数值,并将投放模型输入有限元软件进行分析计算;在0.7MPa荷载下改变投放骨料的粒径和数量得到试件的竖向变形曲线,确定最佳骨料粒径和数量后,对相应数值试件加载不同荷载得到其竖向变形曲线;在10cm×10cm试件中,当骨料粒径为6mm、投放数量为80个时,骨料的空间分布对试件变形基本无影响,此时试件在不同荷载作用下的变形呈线性变化,表现出典型的均质弹性体特征。试验结果表明骨料投放算法的有效性,骨料最大稳定投放数随骨料大小呈幂函数变化,当骨料小到一定值时消除了其空间分布对试件变形的影响。

By means of finite element numerical simulation ,the aggregate random delivery process of the as-phalt concrete numerical specimen is simulated by using Matlab programming .The aggregate of 2.26 mm and below and asphalt are collectively considered as asphalt sand mastic material and the parameters are determined through indoor compression tests .The meshing of the numerical specimen after the aggregate random delivery is conducted ,then the aggregate and asphalt sand mastic material are sorted according to the unit sets and each set possesses corresponding material parameter values ,and the analysis and computation is carried out by the delivery model formed .The vertical deformation curves are given by changing the aggregate size and num-ber under the condition of 0.7 MPa load ,and after the best values of aggregate size and number are deter-mined ,the vertical deformation curves under different loads are obtained .The results show that the aggregate space distribution has almost no effect on the deformation when the aggregate size is 6 mm and the delivery number is 80 in the 10 cm × 10 cm specimen ,specimen deformation under different loads varies linearly ,and such specimen shows typical characteristics of the homogeneous elastomers .The results confirm the effective-ness of the aggregate delivery algorithm .The maximum stable aggregate delivery number is a power function with the change of the aggregate size .In a two-dimensional specimen ,the aggregate spatial distribution will no longer affect the deformation when the size of aggregate is small to a certain value .