Original paper(Vol.48 No.4 pp.346)

Looking Forward Prediction Survey in Near-Surface by Use of Elastic and Electro-Magnetic Reflected Waves

Ashida Yuzuru; Sanada Yoshinori; Shikimori Takayoshi; Nakauchi Takaharu

Abstract:In the present paper, using elastic and electro magnetic reflected waves, the algorithm for imaging the subsurface structure by use of equi travel time planes are proposed and applied to the data for forward prediction survey from tunnel face and the detection of buried pipes.
(1) In the case of looking forward prediction from tunnel face, the new configuration of source and receiver are proposed.
(2) In the case of looking ahead from the radar sensor attached at the top of drilling rod, the algorithm of velocity analysis is proposed in order to determine the velocity distribution in the forward structure. Judging from the present studies, it was concluded that the reflectors with any dip in looking ahead from tunnel face are reconstructed accurately by use of the proposed configuration and the locations of buried pipes were detected those locations with high accuracy.

Key Words:tunnel, buried pipe, elastic reflected waves, electro-magnetic reflected waves, looking forward prediction survey