The effects of mixing time and curing temperature on the uniaxial compressive strength （UCS） andmicrostructure of cemented hydraulic fill （CHF） and sodium silicate-fortified backfill （Gelfill） wereinvestigated i...The effects of mixing time and curing temperature on the uniaxial compressive strength （UCS） andmicrostructure of cemented hydraulic fill （CHF） and sodium silicate-fortified backfill （Gelfill） wereinvestigated in the laboratory. A series of CHF and Gelfill samples was mixed for time periods rangingfrom 5 min to 60 min and cured at temperatures ranging from 5 C to 50 C for 7 d, 14 d or 28 d.Increasing the mixing time negatively influenced the UCS of Gelfill samples, but did not have a detectableeffect on CHF samples. The curing temperature had a strong positive impact on the UCSs of both Gelfilland CHF. An elevated temperature caused rapid UCS development over the first 14 d of curing. Mercuryintrusion porosimetry （MIP） indicated that the pore size distribution and total porosity of Gelfill werealtered by curing temperature.展开更多
A well-developed drainage network was carved in the study area in a hard calcretized and gypcretized gravelly sand of the Dibdibba Formation (Al-Rukham slope) in pluvial episodes in the post-pleistocene age, and is re...A well-developed drainage network was carved in the study area in a hard calcretized and gypcretized gravelly sand of the Dibdibba Formation (Al-Rukham slope) in pluvial episodes in the post-pleistocene age, and is referred to be paleo-drainage due to the current witnessed aridity. This study aims to investigate the geomorphologic, morphometric, and stratigraphic characteristics of the paleo-drainage system and its role in recharging shallow aquifers. Morphometric analysis was accomplished using GIS and remote sensing techniques. Six vertical pit holes were dug across the area to investigate the stratigraphy and recharging capacity. The drainage system is composed of 10 closely spaced, subparallel, dendritic, elongated, and variant-sloped drainage basins with highest stream order of 5. Water flows NE from Al-Rukham ridge’s crest (60 m a.m.s.l.) downstream in Khor Al-Subiyah coastal flat. The bed rock’s hard resistant nature lowered its infiltration and recharging capacity to the shallow aquifer, whereas the coarse-grained wadi fills deposits increased infiltration capacity of the surface sediments, but the water percolation chance is limited as it eventually directed seaward by the same-directed general topography resulting in limiting potential recharge to the shallow aquifers. This is suggested to oppose the salt water intrusion and thus enhance fresh water quality.展开更多
Hydrogeological investigations, tectonics and seismic reflection show the complexity of the Horchane groundwater and drainage possibilities with neighboring groundwater in central Tunisia. Seismic reflection lines int...Hydrogeological investigations, tectonics and seismic reflection show the complexity of the Horchane groundwater and drainage possibilities with neighboring groundwater in central Tunisia. Seismic reflection lines intersecting the region show the role of halokinetic movements, by the intrusion along preexisting faults, in the restructuring of the hydrogeological basin. The salt domes associated with a chaotic facies at the base of outcrops, that limit the Horchane basin, puch to outcrops the areas of recharge area. Geoelectric section shows the anisotropy and the importance of Mio-Plio-Quaternary (MPQ) sediment along the gutters, between the outcrops of El Hafay and Kebar on the one hand, and outcrops of Kebar and Majoura on the other. These gutters are communicated with channels that facilitate drainage of the Horchane complex groundwater by that Gammouda in North-East and Braga in East. The results of this study clearly indicate the important role of the geology in the restructuring of groundwater basins, through early halokinetic movements. (i.e. halokinetic movements). The aquifer geometry is controlled by the ascent of Triassic salt material, from the Middle Jurassic, in central Tunisia.展开更多
The consolidation coefficient is the most basic parameter to calculate the consolidation rate of soil layer, and the horizontal consolidation coefficient controls the radial water flow into the drainage well. Based on...The consolidation coefficient is the most basic parameter to calculate the consolidation rate of soil layer, and the horizontal consolidation coefficient controls the radial water flow into the drainage well. Based on the background of the soft soil in Shantou, Guangdong Province, a series of experimental studies on the consolidation characteristics were carried out by using the modified consolidation instrument. And the concept of the composite consolidation coefficient of the drained water body was put forward. The composite consolidation coefficient reflects the consolidation characteristics of soft soil with drainage water, The test results showed that: 1) The consolidation test with drainage plate is basically consistent with the load compression curve, but its consolidation rate is fast, which is reflected by the composite consolidation coefficient. 2) In the consolidation test of water bodies with drainage, the vertical consolidation coefficient and radial consolidation coefficient are calculated by “three-point method”, and then the composite consolidation coefficient is obtained. The composite consolidation coefficient decreases with the increase of drain spacing ratio, effective drainage diameter and drainage height, which is basically consistent with the theoretical formula. 3) The vertical consolidation coefficient and radial consolidation coefficient decrease with the increase of the diameter of the sample, and the difference is obvious when the load is large. The large-size model with a diameter of 100 mm and a height of 100 mm is about 1.35 times of the vertical consolidation coefficient of the conventional consolidation test.展开更多
机场跑道排水是保障飞机运行安全和飞机品质的关键因素之一,良好的排水系统能够有效排除雨水,减少积水和滞留水的影响。为了探讨现有机场跑道排水系统排水能力,以及降雨与排水系统的演化过程,以中国南方某机场跑道为研究对象,将丹麦水...机场跑道排水是保障飞机运行安全和飞机品质的关键因素之一,良好的排水系统能够有效排除雨水,减少积水和滞留水的影响。为了探讨现有机场跑道排水系统排水能力,以及降雨与排水系统的演化过程,以中国南方某机场跑道为研究对象,将丹麦水利研究所开发的集成的水文水质量模型(Danish Hydraulic Institute model integrated computing,DHI MIKE)模型应用于机场跑道,构建耦合雨洪模型。根据研究区域的降雨特性以及现有排水系统,设计4种不同重现期的降雨情景,从管道充满度、地表淹没结果、跑道积水演化过程3个方面进行模拟分析。结果表明:管道满管数量与降雨强度呈正比关系,不同重现期下研究区域水深的空间分布大体呈一致状态,集中在集水浅沟周围。重现期越大,积水深度越高;出现积水时间和跑道关闭时间提前。跑道排水能力基本能够满足5年一遇的降雨标准。展开更多
基金the financial support given by Natural Sciences and Engineering Research Council of Canada(NSERC)and Valesupport of National Silicate Inc.
文摘The effects of mixing time and curing temperature on the uniaxial compressive strength （UCS） andmicrostructure of cemented hydraulic fill （CHF） and sodium silicate-fortified backfill （Gelfill） wereinvestigated in the laboratory. A series of CHF and Gelfill samples was mixed for time periods rangingfrom 5 min to 60 min and cured at temperatures ranging from 5 C to 50 C for 7 d, 14 d or 28 d.Increasing the mixing time negatively influenced the UCS of Gelfill samples, but did not have a detectableeffect on CHF samples. The curing temperature had a strong positive impact on the UCSs of both Gelfilland CHF. An elevated temperature caused rapid UCS development over the first 14 d of curing. Mercuryintrusion porosimetry （MIP） indicated that the pore size distribution and total porosity of Gelfill werealtered by curing temperature.
文摘A well-developed drainage network was carved in the study area in a hard calcretized and gypcretized gravelly sand of the Dibdibba Formation (Al-Rukham slope) in pluvial episodes in the post-pleistocene age, and is referred to be paleo-drainage due to the current witnessed aridity. This study aims to investigate the geomorphologic, morphometric, and stratigraphic characteristics of the paleo-drainage system and its role in recharging shallow aquifers. Morphometric analysis was accomplished using GIS and remote sensing techniques. Six vertical pit holes were dug across the area to investigate the stratigraphy and recharging capacity. The drainage system is composed of 10 closely spaced, subparallel, dendritic, elongated, and variant-sloped drainage basins with highest stream order of 5. Water flows NE from Al-Rukham ridge’s crest (60 m a.m.s.l.) downstream in Khor Al-Subiyah coastal flat. The bed rock’s hard resistant nature lowered its infiltration and recharging capacity to the shallow aquifer, whereas the coarse-grained wadi fills deposits increased infiltration capacity of the surface sediments, but the water percolation chance is limited as it eventually directed seaward by the same-directed general topography resulting in limiting potential recharge to the shallow aquifers. This is suggested to oppose the salt water intrusion and thus enhance fresh water quality.
文摘Hydrogeological investigations, tectonics and seismic reflection show the complexity of the Horchane groundwater and drainage possibilities with neighboring groundwater in central Tunisia. Seismic reflection lines intersecting the region show the role of halokinetic movements, by the intrusion along preexisting faults, in the restructuring of the hydrogeological basin. The salt domes associated with a chaotic facies at the base of outcrops, that limit the Horchane basin, puch to outcrops the areas of recharge area. Geoelectric section shows the anisotropy and the importance of Mio-Plio-Quaternary (MPQ) sediment along the gutters, between the outcrops of El Hafay and Kebar on the one hand, and outcrops of Kebar and Majoura on the other. These gutters are communicated with channels that facilitate drainage of the Horchane complex groundwater by that Gammouda in North-East and Braga in East. The results of this study clearly indicate the important role of the geology in the restructuring of groundwater basins, through early halokinetic movements. (i.e. halokinetic movements). The aquifer geometry is controlled by the ascent of Triassic salt material, from the Middle Jurassic, in central Tunisia.
文摘The consolidation coefficient is the most basic parameter to calculate the consolidation rate of soil layer, and the horizontal consolidation coefficient controls the radial water flow into the drainage well. Based on the background of the soft soil in Shantou, Guangdong Province, a series of experimental studies on the consolidation characteristics were carried out by using the modified consolidation instrument. And the concept of the composite consolidation coefficient of the drained water body was put forward. The composite consolidation coefficient reflects the consolidation characteristics of soft soil with drainage water, The test results showed that: 1) The consolidation test with drainage plate is basically consistent with the load compression curve, but its consolidation rate is fast, which is reflected by the composite consolidation coefficient. 2) In the consolidation test of water bodies with drainage, the vertical consolidation coefficient and radial consolidation coefficient are calculated by “three-point method”, and then the composite consolidation coefficient is obtained. The composite consolidation coefficient decreases with the increase of drain spacing ratio, effective drainage diameter and drainage height, which is basically consistent with the theoretical formula. 3) The vertical consolidation coefficient and radial consolidation coefficient decrease with the increase of the diameter of the sample, and the difference is obvious when the load is large. The large-size model with a diameter of 100 mm and a height of 100 mm is about 1.35 times of the vertical consolidation coefficient of the conventional consolidation test.
文摘机场跑道排水是保障飞机运行安全和飞机品质的关键因素之一,良好的排水系统能够有效排除雨水,减少积水和滞留水的影响。为了探讨现有机场跑道排水系统排水能力,以及降雨与排水系统的演化过程,以中国南方某机场跑道为研究对象,将丹麦水利研究所开发的集成的水文水质量模型(Danish Hydraulic Institute model integrated computing,DHI MIKE)模型应用于机场跑道,构建耦合雨洪模型。根据研究区域的降雨特性以及现有排水系统,设计4种不同重现期的降雨情景,从管道充满度、地表淹没结果、跑道积水演化过程3个方面进行模拟分析。结果表明:管道满管数量与降雨强度呈正比关系,不同重现期下研究区域水深的空间分布大体呈一致状态,集中在集水浅沟周围。重现期越大,积水深度越高;出现积水时间和跑道关闭时间提前。跑道排水能力基本能够满足5年一遇的降雨标准。
