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在土石坝的蓄水过程中,坝料的持水特性和渗透函数的不同会对坝体渗流场产生很大的影响。因此,对土坡的降雨入渗和土石坝的蓄水渗流场的分析应采用土-水特征吸湿曲线及相应的渗透函数。基于砾石土料的土-水特征曲线的实测结果,采用饱和-非饱和渗流有限元方法对不同程度各向异性的均质土坝初次蓄水过程中由脱湿和吸湿曲线计算所得的渗流场进行对比分析,探讨采用脱湿曲线代替吸湿曲线计算带来的影响。结果表明由脱湿曲线计算的孔隙水压力和体积含水率均明显高于由吸湿曲线计算的结果,渗透性的各向异性程度对坝体中的水力滞后性无明显影响。因此,在入渗分析时若采用脱湿曲线取代吸湿曲线会高估坝体中的孔隙水压力和含水率,低估非饱和区的吸力。
In the process of water storage of earth-rockfill dam, the water-holding characteristics and permeability function of the dam material will have a great impact on the seepage field of the dam. Therefore, soil-water characteristic hygroscopic curves and corresponding infiltration functions should be used for the analysis of rainfall infiltration into soil slopes and storage seepage fields of earth-rock dams. Based on the measured results of soil-water characteristic curves of gravel soil, the seepage field calculated from the desorption and absorption curves during the initial impoundment of anisotropic homogeneous earth dam with different degrees of anisotropy is obtained by using the saturated-unsaturated seepage finite element method Comparative analysis to explore the use of desorption curve instead of hygroscopic curve calculation impact. The results show that the pore water pressure and the volumetric water content calculated by the desorption curve are obviously higher than those calculated by the hygroscopic curve. The degree of anisotropy of permeability has no obvious influence on the hydraulic hysteresis in the dam. Therefore, if the desorption curve is used instead of the hygroscopic curve in the infiltration analysis, the pore water pressure and water content in the dam will be overestimated, and the suction in the unsaturated zone will be underestimated.