Study on application of borehole radar reflection imaging in the detection of karst area

Karst area are widely distributed in China, and complex karst phenomena have great influence on the safety of building site and foundation stability and site survey. As a geophysical method in the well, borehole radar can make use of the difference of physical properties of underground media to find out the situation of karst development, and make up for the shortcomings of the conventional survey methods in detecting karst development sites. The characteristics of the homogenous axis of the single-hole radar reflection signal, the travel time of first arrival wave of the reflected wave and the attenuation of the reflection wave, can be used to determine the distribution of uncovered karst caves and fissures around the borehole. This technique method can also be applied to identifying the diameter of karst caves in horizontal direction and intact rocks surrounding the caves. Borehole radar detection can find out the size, density and spatial distribution of various karst forms, so as to provide accurate and detailed geological data for the design and construction of various engineering construction projects, and to ensure the stability of the projects.