Abstract:

This paper regarded flowing granular media as weak transverse isotropic media, and deduced the phase velocity expressions of wave P. wave SH and wave SV. The propagation specialties of waves in flowing granular media have been analyzed in terms of specialties of wave propagation one could deduce that vibrating waves had less influence on flowability of granules when the amplitude and frequency were small. However, when the amplitude and frequency increased gradually, the granules had better flowabillty. The results of experiment proved that the analysis and the conclusions were correct.

l.
INTRODUCTION

There are many kinds of granular aided flow method, in which vibrating aided flow is widely applied because of its practicality, convenience and efficiency. The technology of vibrating ore- drawing is the application of vibrating aided now in the mining industry. In 1957, the first vibrating ore-drawing machine in the world successfully developed in Russia. In the middle of the 1970's, the technology or vibrating ore-drawing mechanism began to be emphasized in China. The first vibrating ore-drawing machine in China was successfully developed in 1974(Wu, 1991). The overseas applied research about the technology of vibrating ore-drawing is close to perfection. However, there are still many areas need to be looked into some basic theory researches, such as the propagating and attenuating characteristic of vibrating waves in the flowing granular ores, the influence of vibrating waves on the granular ores' mechanical characteristic, etc. This article will analyze the propagating law of vibrating waves in flowing granules and the mechanism of the vibrating aided flow by utilizing wave mechanics.

2.
THE ELLIPSOID IN THE GRANULAR FLOWING FIELD

The ellipsoids in the granular flowing field are mainly the withdrawal ellipsoid and the loosening ellipsoid (Wang. 1988). The withdrawal ellipsoid is also known as the withdrawal body. It refers to a certain volume of granular ores which are drawn through hoppers in stopes. The ores do not flow from the random body in stopes, but from the body which has the approximate ellipsoid shape. The experiment testify that when the granules are drawn from one hopper and turned into the state of motion are not all granular ores in the stope but are partial granules on the hopper opening. The area where granular ores move, the granular shape can be seen by the withdrawal of ore model. If the motion areas are collated its shape is approximate to an ellipsoid.

3.
WAVE PROPAGATION IN THE FLOWING FIEI.D
3.1
Body wave in the granular media

The body wave in the granular media is fallen into wave P and wave S (Wu,1997). lf the appropriate coordinate plane (x,O,y) is chosen the wave propagation direction n will be always parallel to the plane. The wave is not dependent on z coordinate. For the longitudinal wave (wave P), the displacement vector is perpendicular to the wave front; so the wave propagation direction will be always parallel to the plane (x,O,y). The displacement vector of wave S can be resolved into two components.

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