Abstract: A new displacement time series predicting model was proposed by integrating support vector machine (SVM) and Elman neural network, named as SVM-Elman model. In the process of measured displacement data learning, by searching the best historical step and the best prediction step, SVM model was optimized by particle swarm algorithm to dynamically forecast the trend of development. In the meantime, Elman neural network has the ability of dynamically reflecting the development trend of the absolute error of SVM model prediction. By comparing the influence of different hidden layers of Elman neural network on the prediction results, the optimal number of hidden layer was determined for SVM-Elman model and hence modifying the predicted data of SVM in real time. The proposed SVM-Elman model was applied to the strong unloading high slope on the left bank of a concrete face rockfill dam, and the prediction result was compared with that of conventional SVM. Results demonstrate that the proposed model has superior accuracy and real application value in predicting the deformations of high slope.

Key words: prediction of high slope displacement, support vector machine, Elman neural network, SVM-Elman model, particle swarm optimization algorithm, number of hidden layer