基坑的稳定性评价及预测分析,能及时反馈基坑的变形动态,对基坑工程的安全评价具有至关重要的作用。利用尖点突变理论及Spearman秩次检验对基坑的稳定性进行分析,并利用AR(1)模型剔除基坑原始变形序列的相关性,以探讨数据相关性对基坑稳定性分析结果的影响;随后,再利用灰色模型对基坑的变形进行预测,以分析基坑变形的发展趋势,验证稳定性分析的准确性。经实例检验,结果表明:尖点突变分析与Spearman秩次检验的稳定性分析结果一致,均得出基坑变形将趋于稳定,且剔除基坑变形序列的相关性将使稳定性分析结果趋于保守和安全;同时,灰色模型外推4个周期的变形均呈减弱趋势,与稳定性分析结果相符。通过上述3种分析方法能从不同方面对基坑的稳定性进行评价及预测分析,具有较好的一致性,为类似工程实践提供了一定的参考依据。

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.