Abstract:The groundwater level is a key factor influencing the subgrade settlement. However, the conventional curve-fitting prediction method only considers the relationship between time and settlement, and neglects the impact of groundwater level fluctuations, which limits the accuracy of settlement predictions. Taking the soft subgrade expressway in Jiangsu Province as the study object, the groundwater level and settlement are monitored by embedding the sensors to deeply discuss the effect of groundwater level variations on the settlement rule of soft subgrade. Based on a BP neural network, the relationship model containing the time, groundwater level and settlement is built. Comparing the measured data with the traditional curve-fitting model, it is found that the settlement prediction value of BP neural network model is positively correlated with the groundwater level, and the average prediction error is only 0.17%. Compared with the traditional method, the precision is improved by 3.58%. The study result shows that the BP neural network settlement prediction model can effectively consider the influence of groundwater levels, and the accuracy of settlement prediction of soft subgrade is greatly improved.