Introduction

Abstract

Anything comprising a great quantity of similar grains is termed as the granular medium (in general, it is called granules), such as the broken ores, sands, slurry, fine coals, cements, corns, etc. Especially, the broken ores and sands are usually applicable in this study^{[1 ∼ 4]}. With the development of modern engineering techniques, the fields involving the granular dynamics are rapidly increasing. The so-called dynamical forces are mainly produced by seismism, rock-burst, wind’s vibration, wave, mechanical vibration, blasting, etc. In engineering practices scientists and engineers are deeply concerned with two issues, one is the prevention of vibrating hazards and the other is the use of vibrating energy.