Reliability Assessment of Tunnel Based on P -Wave Seismic Velocity

This paper aims to propose a new method to analyze the stability of a tunnel using P-wave seismic velocity (Vp) with the help of the Tunnel Seismic Prediction 203 plus system (TSP203PLUS). On one hand, the relationship between Hoek-Brown constants such as the geological strength index (GSI) and the disturbed parameter (D) and Vp is investigated. On the other hand, the displacement of the tunnel is derived using the Hoek-Brown criterion, but it is hard to determine the Hoek-Brown constants because uncertainties are abundant in geomaterials. Fortunately, Vp can be read from TSP203PLUS, which is an essential approach to predict geohazards in tunnels, and it is widely used during tunnel excavation. A series of parameters such as Young’s modulus, Poisson’s ratio, and the Vp of rocks can be read from TSPwin (the software for processing data in TSP203PLUS). However, a precise prediction of Vp and other parameters depends mostly on the experience of the engineers. In order to eliminate the uncertainties due to the different engineers, it is reasonable to standardize the parameters as normal variables; then the stability of the tunnel can be calculated based on the response surface method (RSM), and the stability of the tunnel is represented by the probability of failure. To demonstrate the usefulness of this approach, a tunnel located in China is assessed and the results are validated by Monte Carlo simulations. The proposed method provides a convenient and effective method to study the reliability assessment of tunnels.