基于2σ-chauvenet准则的POT模型的膨胀土渠坡位移监控指标拟定

Development of Monitoring Index of Channel Slope Displacement Based on 2σ-chauvenet Criterion POT Model

在深挖方膨胀土渠坡的长期服役过程中,借助位移监控指标实时辨识渠坡服役性态是确保渠坡安全运行的重要手段,因此拟定合理的监控指标对于保障渠坡工程的安全具有重要意义。在POT模型的基础上,引入2σ准则和chauvenet准则,建立了阈值与监控指标之间的对应关系,通过求解满足该对应关系下的最佳阈值,建立了膨胀土渠坡位移监控指标拟定的改进POT模型,并应用于南水北调中线工程陶岔段的深挖方膨胀土渠坡工程中。结果表明,相较传统POT模型,基于2σ-chauvenet准则的改进POT模型可有效避免主观性与随机误差,具有更高的计算精度,拟定的位移监控指标更偏于安全,对防范渠坡风险、确保渠坡安全长效运行具有更强的指导意义。

In the long service process of the deep excavated expansive soil channel slope, the real-time identification of the service behavior of the channel slope by means of displacement monitoring index is an important means to ensure the safe operation of the channel slope. Therefore, it is of great significance to formulate reasonable monitoring indexes for the safety of canal slope engineering. The POT model was presented in this paper. On the basis of introduction of 2 σ criteria and chauvenet principles, the threshold T and the corresponding relation between monitoring index was established. Through the best solution to satisfy the relationship between threshold, a canal slope displacement monitoring index for improved POT model was established to apply to the Taocha section of South-to-North Water Transfer Project of deep excavation expansion earth canal in slope engineering. Compared with the traditional POT model, the results show that the improved POT model based on 2σ-chauvenet criterion can effectively avoid subjectivity and random error, and it has higher calculation accuracy. The proposed displacement monitoring index is more safety, which has stronger guiding significance to prevent the risk of canal slope and ensure the safe long-term operation of canal slope.