堤防渗流风险的定量评估方法

Quantitative assessment of embankment seepage risk

从渗流风险的不确定性分析出发,分别考察了影响渗流风险的主要随机因素出逸比降和临界比降,着重分析了在一定水位差条件下的边界、地质等土力因子随机特性。在此基础上,建立了定量预测堤防渗流风险率的实用模型,给出了水位高程与渗流风险之间的关系。提出了通过实际的渗流险情原观资料对模型进行反馈率定的方法,讨论了非稳定渗流条件对模型精度的影响及改进方法。本文提出的模型可预测未曾发生过的高洪水位工况下的堤防渗流风险率。

The stochastic characteristics of escape gradient and critical gradient are studied based on the analysis on the uncertainty of seepage risk. Attention is concentrated on the stochastic properties of boundary and geological factors under certain difference of water levels. On this basis, a practical model for quantitatively predicting the risk of embankment seepage is established and the relationship between water level and seepage risk rate is derived. The feedback method for calibrating the model by using prototype observation data is suggested. The effect of unsteady seepage on accuracy of this model and the method for improving the accuracy are studied. By using this method the seepage risk rate of embankment under the condition of high flood level never occurred in history can be predicted.