中文摘要：

将多根连接钻杆近似为无约束的一维杆状体,阐述了轴向激发的弹性波在钻杆中一维纵波的传播规律：弹性波传播到钻杆顶端将产生能量较强的反射波;钻杆中弹性波各振型频率的差为一定值,且随着杆长的增加而减小.通过在钻杆底端激发、接收弹性波,利用钻杆顶端的反射波的到时和弹性波各震相的频差,根据已标定的弹性波在钻杆中的传播速度分别从时间域和频率域计算钻杆的长度,从而确定钻孔的深度.对煤矿瓦斯抽采孔进行快速抽查,取得了很好的效果.

英文摘要：

Rapid decision of drilling depth is an urgent requirement in coal mine management and safety production.Since a drilling pipe can be assumed as a one-dimensionalbolt unconstrained,one-dimensionalwavepropagation law of elastic waves stimulated axially is expounded.There will be a clearly defined reflection when elastic waves reach the top of the bolt.The frequency difference of seismic phases which is fixed in an elastic wave decreases with the increase of the bolt length.Based on one-dimensionalwavepropagationandreflectionlaws,elastic waves can be excited and received at the end of the drilling pipe,and then,accordingtothe time that reflected waves take to reach the top of the bolt and the frequency differences of seismic phases,the bolt length can be calculated in time field andfrequency field so that the depth of drilling hole can be determined.This method has been proven effective by fieldtest,which realizes the rapid and efficient measurement of drilling-hole depth.