Abstract:

In the management of the karst fissure water, the 3D extension law of the water-bearing formation and the hydraulic cross-connection of fissures which are difficult to find out are key factors of the construction time limit and the cost of engineering. The ground penetrating radar (GPR) detection in karst area is affected by strong interference, multiple solutions, signal distortion; so the grid method is put forward based on the probability theory. Based on the electromagnetic wave propagation theory, the energy distribution law of the reflection and refraction on the interface of the water-bearing formation is researched. The mechanism of the water-bearing thin bed on the low frequency reflection signal of radar is analyzed. The criteria of the detection of water-bearing fissure in the karst area are discussed. Combined with the example of the karst-water management in the Qiyueshan tunnel floor, the applications of GPR to the detection of the water-bearing extension law and the choice of the best grouting hole are described. The conclusions can bring the ecological, safe and economic benefits; and the research can provide a reference for similar projects.

Key words: ground penetrating radar (GPR), grid method of radar survey line, pressing of low frequency, criteria of water-bearing fissure, best grouting hole