基于元胞自动机模型的堆积体动力学参数研究

Study of dynamic parameters for talus deposit based on model of cellular automata

堆积体是一种典型的二元介质,由软弱的基质土与坚硬的碎、块石构成。利用元胞自动机模型对随机离散单元进行演化,模拟堆积体的分布结构、"聚团"特征;利用弹性应力波传播原理计算波的等效速度,研究了堆积体内介质分布、软硬程度对动力学参数的影响规律。研究发现,堆积体内的波速由基质与充填物共同决定,基质材料越弱,地震波传播速度越慢,二者呈对数变化;堆积体内碎石含量越高,则波速越快,波速与充填碎石块含量呈对数关系增长,而振幅系数与碎石含量关系不大,主要取决于碎块石的分布结构;由于堆积体介质密度不均,导致堆积体内波传播速度与入射波频率密切相关,高频波速度快、低频波速度慢,横波速度与入射波频率成指数递增关系。研究表明,采用基于元胞自动机模型研究动变形参数,可以更好地反映出堆积体的波动力学性能,是一种获得复杂介质动参数的重要方法,可以弥补室内及现场试验的不足。

As a typical binary medium,talus deposit is made up of weak parent soil,stiff macadam or rock blocks.Cellular automata model is used in evolution of random and discrete elements to simulate the distribution structure and accumulation characteristics;then equivalent wave speed is calculated according to transmission theory of elastic stress wave;then the influence on dynamic parameters of medium distribution and rigidity are studied.The results show that the wave speed in talus is controlled by parent medium and fill medium;the more faint the parent medium is,the more slow SV speed is;it exhibit as logarithm relation.The more content of rock filling can make more high wave speed;the speed and content of rock filling takes as logarithm relation,while there＇s little correlation between amplitude ratio and rock filling;it primary depends on distribution construction.Due to the inhomogeneous density of talus,wave speed is closely related with incident wave frequency;high frequency makes high wave speed and low frequency makes low wave speed.With this method,the wave mechanics can be better considered;dynamic parameters of complex medium can be effectively achieved;and shortage of indoor and field tests can be greatly improved.