Prediction of undrained shear strength of shallow seabed ultra soft clay based on BP neural network
Accurately evaluating the undrained shear strength of shallow ultra soft clay on the seabed is of great significance for marine resource development,disaster assessment,and marine engineering construction.The analysis and comparison of data on ultra soft clay in several sea areas around the world show that the existing empirical formulas for undrained shear strength assessment are limited by geographical regions and have low calculation accuracy.Therefore,taking six physical properties of ultra soft clay as input variables and undrained shear strength as output variables,a BP neural network model is established to predict the undrained shear strength of shallow ultra soft clay on the seabed.Based on the established nonlinear mapping network between the undrained shear strength and physical properties of ultra soft clay,the sensitivity coefficients of the undrained shear strength of ultra soft clay to each index are solved using the weight product method,and the influence of each index on the undrained shear strength is quantitatively analyzed.The results show that the BP neural network model considering multiple factors has universal adaptability in predicting the undrained shear strength of ultra soft clay.Its prediction results are very close to the measured results of the cone drop test,with a mean square error of 0.021 39 and R2 reaching 0.987 4.The prediction accuracy is much higher than existing empirical formulas.The undrained shear strength is most sensitive to the logarithmic liquidity index calculated by the weight product method.Based on this,an empirical formula for predicting the undrained shear strength of clay using logarithmic fluidity index as a parameter was established.This formula has high accuracy in calculating the undrained shear strength of ultra soft clay in Chinese waters.Due to the limited data,there are still certain limitations.This study provides a method reference for calculating the undrained shear strength of ultra soft clay in shallow seabed layers.
万方数据
维普
