基于HYDRUS模型渠道渗漏模拟及影响因素分析

The Channel Leakage Simulation and Its Influence Factors Analysis Based on HYDRUS Model

为探明影响有压入渗渠道渗漏的主要因素,采用恒水位静水试验的方法开展渠道渗漏试验,试验设置8个入渗水头,探究不同水深情况下渠道的累积入渗量及入渗速率的变化规律,并选用HYDRUS-2D软件进行模拟分析。结果表明:实测值与模拟值的变化规律基本吻合,入渗速率的RMSE值为0.003 6~0.376 3 cm/h,累积入渗量的RMSE值为0.001 7~0.300 9 m^3,R^2的值均达到0.9以上,说明选定的土壤水分运动方程合理,选取的相关参数值合适,用于渠道渗漏评价是可行的。采用HYDRUS-2D模型野外拓展试验对渠道水深、底宽及边坡系数进行影响分析,渠道水深的变化对入渗速率的影响较大,而渠道底宽、边坡系数的变化对入渗速率的影响较小。渠道水深、底宽及边坡系数对累积入渗量的影响均呈现极显著相关(P<0.01),对累积入渗量的影响程度大小为渠道水深>渠道底宽>边坡系数。其中渠道底宽和边坡系数的交互作用对累积入渗量的影响并不显著(P>0.05),渠道水深和边坡系数的交互作用对累积入渗量的影响呈极显著相关(P<0.01),渠道水深和底宽的交互作用对累积入渗量的影响同样呈极显著相关(P<0.01)。研究结果为探明渠道水分入渗规律、改进渠道防渗技术及开发新的的渠道渗漏损失计算方法等提供参考。

In order to find out the main factors affecting the leakage of pressure infiltration channels, the constant water level static water test method was adopted to carry out the leakage test of channels. Eight infiltration heads were set up to explore the change rules of the cumulative infiltration amount and infiltration rate of channels under different water depths, and Hydrus-2 D software was selected for simulation analysis. The results showed that the simulated values and measured values were basically consistent. The RMSE values of infiltration rate were 0.003 6 ~ 0.376 3 cm/h, and RMSE was 0.001 7 ~ 0.300 9 m^3 for cumulative infiltration amount, the average of R^2 was always more than 0.9, indicating that the soil water movement equation and its related parameters were reasonable, the channel leakage evaluation was feasible. The influence of water depth, bottom width and slope coefficient were analyzed by field expansion test of Hydrus-2 D model. The results showed that the change of channel water depth had a great influence on the infiltration rate, while the change of channel bottom width and slope coefficient had a small influence on the infiltration rate. The influence of channel water depth, bottom width and slope coefficient on cumulative infiltration amount was extremely significant(P < 0.01), and the degree of influence on cumulative infiltration amount was: channel water depth > channel bottom width > slope coefficient. Among them, the interaction between channel bottom width and slope coefficient had no significant influence on cumulative infiltration amount(P > 0.05), but the interaction between channel water depth and slope coefficient had an extremely significant correlation with cumulative infiltration amount(P < 0.01), and the interaction between channel water depth and slope width had an equally significant correlation with cumulative infiltration amount(P < 0.01). This study could provide a reference for exploring the rule of water infiltration, improving the technology of seepage prevention and developing a new method for calculating leakage loss.