Accuracy of Non-Destructive Estimation of Length of Soil Nails

The effective length of soil nails is one the critical parameters ensuring reinforcing effect, and its accurate estimation great significance for safety slope deep foundation pit supporting projects. Traditional quality insurance methods, such as nail pullout tests, suffer from a series drawbacks including being destructive, high cost, time-consuming. In contrast, non-destructive testing (NDT) has been increasingly applied in various engineering fields past decades given advantages not damaging material easy operation. However, current application NDT measurement relatively limited, accuracy reliability are yet to be quantitatively evaluated. This paper introduces three methods estimating based on guided wave theory collects 116 sets data length. prediction statistically analyzed using model bias method. results show that those can accurately predict with an average error less than 3% low dispersion 12%. affected by hammer type or Furthermore, this proposes calibration original method, which improves model’s reduces 4% without increasing computational complexity. Finally, probability distributions biases characterized. study provide practical tools fast situ length, slopes pits.