Abstract: Stability evaluation and prediction is of crucial significance for the safety evaluation of foundation pit as it gives timely feedback to the deformation behavior of the foundation pit. In the present research, the stability of foundation pit is analyzed by using cusp catastrophe theory and Spearman rank test; furthermore, the influence of data dependency on stability result is investigated through decorrelation of original deformation sequence by AR(1) model; finally, the correctness of stability analysis is verified by grey model. Case study demonstrates that the stability result obtained from cusp catastrophe analysis agrees well with that of Spearman rank test, both indicating that the deformation of foundation pit tends to stabilize. Decorrelation processing of the data could make the result conservative. In the meantime, the deformation obtained by grey model extrapolation of four cycles all tend to decrease, conforming with the stability analysis. The abovementioned three methods could all evaluate and preduct the stability of foundation pit, and the results are consistent.

Key words: foundation pit, cusp catastrophe theory, Spearman rank test, GM (1,1) model, stability analysis