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• Main Authors: CHENG MING-LIANG, 鄭名良
• Other Authors: 李明旭
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/3dau6c

碩士 === 國立中央大學 === 水文與海洋科學研究所 === 105 === Traditionally, the water retention curve is measured at rest. However, the experimental evidence found that the desaturation rate changes the water retention curve known as the dynamic effect of water retention curve. It is difficult to observe the dynamic effect because the tensiometer itself does not respond to the rapid changes in water pressure. The tensiometer delay will inevitably have an impact on the measurement, while the experimental measurement of dynamic capillary pressure mostly ignores the tensiometer delay effect. In this study, a series of indoor sandbox experiments were performed to measure static and dynamic water retention curves, and we also perform the experiments to quantify the delay coefficient k. To explore the factors that affect the delay factor. In addition, the sand column drainage experiment was conducted to measure the cumulative flow rate to understand the effects of static and dynamic water retention curves and tensor delay effects on simulated one-dimensional drainage simulation. The results show that the static and dynamic water retention curves are more pronounced after the modified capillary pressure by considering delay effects. Nevertheless, the VG parameters of the modified water retention curve n increases but the α is reduced, making the difference between the simulated one-dimensional drainage of the cumulative outflows with the original and modified water retention curve is insignificant. The simulation results show that the simulated sand column drainage with the dynamic water retention curve with a flow rate of 1.11 cm3/s is closest to the experimental results. The result of the experiments for delay coefficient shows that the delay coefficient of the ceramic head significantly reduced when the head has been used for a long time, the delay coefficient decreases as the decrease of the glass sand size increases, and the delay coefficient increases with the effective saturation.