A new method for detecting karst and groundwater by 3D seismic wave: case study of the karst tunnel in Zhangjihuai Railway, China

Karst and groundwater are major geological disasters that can easily occur during tunnel construction. How to accurately predict and detect the groundwater and caves during tunnel construction in karst strata is a very challenging problem. In this regard, there are few effective detection methods in the literature. Based on the theory of seismic wave propagation dynamics, we proposed a new method to evaluate the seismic wave stress response of the reflection interface in order to detect the existence of karst in the Zhangjihuai railway tunnel. The stress gradient characterizing the pore state formula of rock mass was obtained, and the relationship between the stress gradient and the evaluation value of groundwater was established based on the two-phase media wave and fluid mechanics theories. A 3D seismic wave field observation system and detection method suitable for the tunnel construction environment was proposed and a field study was carried out. The test results verified the effectiveness of the new method in detecting karst and groundwater, and a hydrogeological identification method for karst cave was proposed. The characteristics of the water-free cavity were dσ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{d}}\sigma$$\end{document} ≥10 and ν\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upnu$$\end{document}<20%, and the characteristics of water-filled cavity were dσ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{d}}\sigma$$\end{document} ≥ 10 and ν\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upnu$$\end{document} > 40%.