In the process of mining in underground coal face

it is the guarantee of safe and efficient production of coal mine to grasp the abnormal situation in front of coal face in time. Ground penetrating radar (GPR) is an efficient and non-destructive detection method

which is widely used in mines. Significant achievements have been made in the image interpretation and imaging accuracy of GPR for detecting abnormal body response

but how to delineate the location and spatial distribution of geological abnormal body with GPR is a hot research issue. In this paper

a new method

which combines multiple sections and linear interpolation

is developed for accurate detection of abnormal body in coal mining face. The main research ideas are as follows. Firstly

forward simulation of 3D model of coal seam cavity and fault is carried out by using finite difference time domain algorithm (FDTD)

and the response range of abnormal body is roughly delineated by Kirchhoff migration. Secondly

the multi-section view of single channel wave data with abnormal body response was obtained

and the exact position coordinates and specific dimensions of abnormal body were determined by linear interpolation

and the area evaluation criterion was introduced to verify the similarity of detection results. Finally

a GPR of LTD-2600 and a 900 MHz shielded antenna were used to conduct field experiments on the constructed physical cavity model

and the calculated cavity profile was compared with the actual cavity size for verification. The proposed method was applied in 18201 face of Xiegou coal mine to verify its validity. It is proved by practice that the error between the measured and actual spatial positions is less than 10%

and the specific size and spatial distribution range of abnormal bodies can be delineated relatively accurately.