TETSP-2隧道地震超前探测系统利用三分量检波器接收地震信号,迫切需要将数据中的纵横波信息分离。文章由隧道内线性观测系统的反射纵横波时距曲线进行推导，并基于Taylor理论分析τ-p变换在隧道地震超前探测中的物理意义和可行性，给出τ-p变换截距和慢度与反射界面倾角的关系，模拟简单条件下二维隧道空间内的地震全波场，分析不同波场的反射特征，比较不同倾角情况下反射纵横波在τ-p变换域中的特征及差异。结果表明: 不同倾角反射纵横波的视速度不同，随着倾角逐渐变小，视速度变大。τ-p变换能够利用视速度差异进行波场分离，在隧道前方低速带倾角较大时(40°以上)，分离效果较好；在倾角较小时，时距曲线的一阶Taylor展开式具有较大误差，分离效果变差。

As a result of the use of a threecomponent geophone to receive seismic signals in TETSP2 tunnel seismic advance detection system; it is urgent to separate the mixed information such as primary wave and secondary wave in seismic wavefield. In this paper, the timedistance curve of the reflected longitudinal and transverse wave in the tunnel is deduced; the applicability of the τp transform in the tunnel seismic advance detection is theoretically analyzed based on Taylor′s formula; and the relationships between nodal increment and slowness of τp transform and reflection interface dip angle are given. And then the whole wavefield in the twodimensional tunnel space under simple conditions is simulated; the reflection characteristics of different wavefields are analyzed; and the characteristics and differences of reflection Pwave and Swave in τp transform domain are compared under different dip angles. The results show that: (1) The apparent velocity of reflection transverse wave under different dip angles varies, and the apparent velocity increases with dip angle decrease. (2) The τp transform can separate wavefield relying on different apparent velocity between primary wave and secondary wave; the method can well separate the wavefield when the dip angle of low speed zone in front of tunnel face is no less than 40°; but when the dip angle is small, the firstorder Taylor expansion of timedistance curve has a large error, which makes the effect of wavefield separation bad.