APPLICATION OF ARMA MODEL IN DEFORMATION MONITORING AND FORECASTING OF ANCHORAGE FOUNDATION PIT

This paper introduces the time series prediction principle,the basic model and the prediction procedure in detail. It uses the measured data of foundation pit displacement and crack deformation during the construction of the foundation pit of Xintian Yangtze river bridge. It establishes the Autoregressive Integrated Moving Average Model(ARMA)using the time series method. On this basis,the deformation trend of the foundation pit and the crack of the dangerous rock in the construction process are predicted. The model prediction data are compared with the international monitoring data. The results show that the ARMA model can solve the problem of data instability by using difference algorithms,and has higher accuracy in the short-time prediction period. With the increase of the prediction period,the prediction accuracy of ARMA model decreases. The reason is that with the increase of the prediction period,the historical data on which the prediction relies are decreases. Therefore,when establishing the ARMA model,new data should be added regularly to avoid the reduction of prediction accuracy caused by too long prediction period. The research results of this paper can be a reference for the monitoring research of similar projects in the future.