There exist many fluvio-glacial deposits in the valley of Dadu River, Southwest China, which dates back to the Pleistocene. As some of the deposits are located within the seasonal water fluctuation zone of reservoirs,...There exist many fluvio-glacial deposits in the valley of Dadu River, Southwest China, which dates back to the Pleistocene. As some of the deposits are located within the seasonal water fluctuation zone of reservoirs, the seepage of groundwater acts as one of the key factors influencing their stability. Investigation into the sediment properties and permeability is, therefore, crucial for evaluating the sediment stability. In this study, in-situ permeability and sieving tests have been carried out to determine grain size distribution, correlations of permeability and hydraulic gradients, and relations between permeability and sedimentation properties. Test results indicate that the deposits are composed mostly of sands, gravels, cobbles and boulders, and the percentage of fines is less than 5%. The sediments have high densities, low porosities and natural moisture contents. At low hydraulic gradients, the seepage velocity obeys the Darcy＇s law, while a non- Darcy permeability is observed with hydraulic gradient exceeding a certain value （about 0.5 - 0.7）. The linear permeability coefficient ranges from 0.003 to 0.009 cm/s. Seepage failure occurs above a threshold between 1.1 and 1.5. The test data fit well with the non-linear permeability equations suggested by Forchheimer and Izbash. The non-Darcy permeability proves to be in accordance with the seepage equation suggested by Izbash with the power ＇m＇ of about 0.6 - 0.7. The characteristic grain sizes of the studied deposits are found in a narrow range between 0.024 and o.o31 mm, which is much lowerthan the effective grain size （dlo）.展开更多
The DID （Department of Irrigation and Drainage） in Malaysia has produced a manual on urban stromwater management specifically for the Malaysia region with usage of infiltration method towards controlling the quantit...The DID （Department of Irrigation and Drainage） in Malaysia has produced a manual on urban stromwater management specifically for the Malaysia region with usage of infiltration method towards controlling the quantity and quality of surface runoff. With this method, the volume of surface runoff can be reduced and flood problems in major cities can be eliminated. The study areas of Sungai Kedah ungauged catchment are located at the northern region of Malaysia. The Kota Setar sub-catchment is located at the downstream of Sungai Kedah with the newly completed development of control barrage at the upper Kota Setar. This paper will describe the analyses of the infiltration curves at Kota Setar. The resulting infiltration maps have developed based on the infiltration capacities.展开更多
During the construction of the south caisson anchorage of Taizhou Bridge, the drainage area is located in the lower reaches of the Yangtze River and the permeability of stratums there is considerable. In order to main...During the construction of the south caisson anchorage of Taizhou Bridge, the drainage area is located in the lower reaches of the Yangtze River and the permeability of stratums there is considerable. In order to maintain progress and guarantee safety during the sinking of the caisson, water should be drained in the initial period. Subsequently, detailed information about the aquifer permeability is required to make sure that the drainage will proceed successfully, which consequently necessitates the on-site estimation of the aquifer permeability in the drainage area. Therefore, the traditional pumping test and slug test are implemented respectively on site. The comparison of computational results of these two tests indicates that they are consistent overall. Notwithstanding, as slug test can be conducted with portable facilities in a short time and the manipulation is easy and few people need to be involved, the advantages of slug test is conspicuous compared with the traditional pumping test. It could be speculated that slug test will gain a prevalent application in the measurement of aquifer permeability in the future.展开更多
基金supported by the National Natural Fundation of China (41202212)Independent Subject Foundation of SKLGP (SKLGP2012Z006)
文摘There exist many fluvio-glacial deposits in the valley of Dadu River, Southwest China, which dates back to the Pleistocene. As some of the deposits are located within the seasonal water fluctuation zone of reservoirs, the seepage of groundwater acts as one of the key factors influencing their stability. Investigation into the sediment properties and permeability is, therefore, crucial for evaluating the sediment stability. In this study, in-situ permeability and sieving tests have been carried out to determine grain size distribution, correlations of permeability and hydraulic gradients, and relations between permeability and sedimentation properties. Test results indicate that the deposits are composed mostly of sands, gravels, cobbles and boulders, and the percentage of fines is less than 5%. The sediments have high densities, low porosities and natural moisture contents. At low hydraulic gradients, the seepage velocity obeys the Darcy＇s law, while a non- Darcy permeability is observed with hydraulic gradient exceeding a certain value （about 0.5 - 0.7）. The linear permeability coefficient ranges from 0.003 to 0.009 cm/s. Seepage failure occurs above a threshold between 1.1 and 1.5. The test data fit well with the non-linear permeability equations suggested by Forchheimer and Izbash. The non-Darcy permeability proves to be in accordance with the seepage equation suggested by Izbash with the power ＇m＇ of about 0.6 - 0.7. The characteristic grain sizes of the studied deposits are found in a narrow range between 0.024 and o.o31 mm, which is much lowerthan the effective grain size （dlo）.
文摘The DID （Department of Irrigation and Drainage） in Malaysia has produced a manual on urban stromwater management specifically for the Malaysia region with usage of infiltration method towards controlling the quantity and quality of surface runoff. With this method, the volume of surface runoff can be reduced and flood problems in major cities can be eliminated. The study areas of Sungai Kedah ungauged catchment are located at the northern region of Malaysia. The Kota Setar sub-catchment is located at the downstream of Sungai Kedah with the newly completed development of control barrage at the upper Kota Setar. This paper will describe the analyses of the infiltration curves at Kota Setar. The resulting infiltration maps have developed based on the infiltration capacities.
基金Special Fund of"333"High Level Talent Training Project of Jiangsu ProvinceNational Scienceand Technology Support Program of China ( No. 2009BAG15B02) Key Programs for Science and Technology De-velopment of Chinese Transportation Industry( No. 2008-353-332-150)
文摘During the construction of the south caisson anchorage of Taizhou Bridge, the drainage area is located in the lower reaches of the Yangtze River and the permeability of stratums there is considerable. In order to maintain progress and guarantee safety during the sinking of the caisson, water should be drained in the initial period. Subsequently, detailed information about the aquifer permeability is required to make sure that the drainage will proceed successfully, which consequently necessitates the on-site estimation of the aquifer permeability in the drainage area. Therefore, the traditional pumping test and slug test are implemented respectively on site. The comparison of computational results of these two tests indicates that they are consistent overall. Notwithstanding, as slug test can be conducted with portable facilities in a short time and the manipulation is easy and few people need to be involved, the advantages of slug test is conspicuous compared with the traditional pumping test. It could be speculated that slug test will gain a prevalent application in the measurement of aquifer permeability in the future.
