Numerical Simulation And Analysis On The Additive Mass Method In The Density Test

As the industrial economy continues to grow in the new century, the demandfor electricity is getting bigger and bigger. So there are many water conservancy andhydropower facilities being under construction now. In order to ensure the quality ofwater conservancy and hydropower project rock-fill dam, one of the very importanttasks is to monitor the density of the rock-fill dam. The additive mass method iswidely used in the rock-fill dam density monitoring program. But most of the studyon the additive mass method is based on the assumption that the rockfill system iselastic. And the form of the additive mass distribution and the distributionpractically has not been studied. On the other hand, there are many affects to themain frequency in the additive mass method monitoring program. So this article willstudy two main parts basking on the viscoelastic model been established. One is tostudy the form of the additive mass distribution and the distribution. And the other isto study the relationship of the main frequency and the medium parameter. Thespecific content and the results are as follows:Firstly, because of that the form of the additive mass distribution and thedistribution practically has not been studied, the model which has no additive massis analyzed. Then every point’s time history curve of acceleration is gotten out todraw contours of these points’ maximum acceleration. Attention should be taken thatthese points are on the surface passed by the load action point and the load direction.Results show that the mass participating in the vibrating disturbs as semi-ellipsoid.Secondly, the model which has additive mass is analyzed. But distribution ofthe mass participating in the vibrating basically has no change by compared to thatappeared in the model which has no additive mass. The suggested distribution of themass participating in the vibrating is defined in this article. Comparing with a groupof measured data, the distribution fits well.Thirdly, elastic and viscoelastic rock-fill models are established to get thefrequency of them. By changing the model parameters, trend can be drawn out. Inthe elastic models, frequency decreases as the density increase. The frequencyincreases as the elastic modulus increase in a certain range. The effect of Poisson’sratio to frequency is not obvious. And in viscoelastic models, frequency decreases asthe density increase. The frequency increases as the elastic modulus increase. Thefrequency decreases as the Poisson’s ratio increase. And the frequency decreases asthe damping coefficient increase.