A study on the Anti-Clogging Potential of Geotextile by the Reverse Flow

• Main Authors: Kuo-Hai Wang, 王國海
• Other Authors: Dave, Ta-Teh Chang
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/17984708449645878780

碩士 === 中原大學 === 土木工程研究所 === 89 === ABSTRACT In the application field of drainage/filtration of geotextile, the existing reverse water flows always makes the piping takes place much easier even soil soften. The soil mass was washed so that failure happened. However, reverse water flows that are acting on a filtration/drainage system under the unpiping stage will form an anti-clogging affection. A series of simulation tests will perform to study the affections of the reverse water flows to the anti-clogging performance of the geotextiles. In order to estimate affections of the clogging behavior caused by reverse water flows to the soil-geotextiles filtration/drainage system and the performing of soil filtration layer. A test device modified from the Hydraulic Conductivity Ratio Test recommended by Williams and Abouzakhm was used to simulate the test with direct and reverse water flow in a soil. And a set of electronic water pressure transducers were involved into this test to overcome the disadvantage of HCR test which is not able to evaluate the water head distribution inside the soil mass. The electronic water pressure transducers penetrated in to the soil mass through the rubber membrane exactly measured the water pressure distribution inside the soil mass. With consideration the content of fine particles and the gradient of the revere water flows would be the most important influence factors to this application study. There are two geotextiles, two grained soils were used in this study with three gradients of the reverse water flows. Beside, Bubble Point Method was also used to evaluate the pore size distribution of the geotextile before and after the filtration/drainage behavior, then the pore size change of the geotextile in the filtration/drainage behavior would be known. Concluded with the tests results, the influence of reverse water flow to the conductivity of the system is more serious with the 10% fine particles content soil sample（i>=20）reverse water flow condition. The overlay soil would have more chance to perform a piping phenomenon. The influence of the reverse water flow with the 30% fine particles content soil sample the system also showed a better performance to retain the soil particles. By analyzing the test results from modified HCR tests, when the fine particle content of soil sample is lower, the clogging and blocking effect with in the geotextile layer is more serious. And when the fine particle content of soil sample is higher, the main reason of the system conductivity goes down is because of the performing of impervious layer of the soil sample. Before the serious piping stage, reverse water flows perform a positive effect to the geotextile anti-clogging potential. It seems that the reverse water flow is valuable to applied the washing behavior with the geotextile in the filtration/drainage application in order to extend the lifetime of geotextile on filtration/drainage application field.