共查询到20条相似文献，搜索用时 31 毫秒
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Following 35 years of persistent groundwater rise beneath northern Ivanhoe Plain in the Ord River Irrigation Area, northern Australia, the water table appears to have stabilized near the base of the irrigation surface-drain network. Hydrometric evidence indicates that intersection of the deepest surface drains by the rising water table simultaneously reduced aquifer recharge from surface-water infiltration and increased aquifer discharge by groundwater exfiltration. Water-table analysis supports the working hypothesis that the largest irrigation drain D4 on north Ivanhoe Plain has been receiving a significant amount of groundwater discharge since the mid-1990s. The rate of groundwater discharge to surface drains on north Ivanhoe Plain was estimated to be around 15–20 million (M)L/day based on groundwater-flow modelling. Groundwater tracing using radon and electrical conductivity indicated that groundwater discharge to drain D4 was ～6–12 ML/day in August 2007. The rate of groundwater discharge was significantly larger where the drain traverses a very-permeable sand and gravel palaeochannel. Relatively modest exfiltration rates of order of magnitude tens to hundreds of mm/day into the drain were estimated to mitigate 0.5 m/year groundwater accretion for a land area of order of magnitude hundreds to thousands of ha. 相似文献
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Golmar Golmohammadi Ramesh Rudra Shiv Prasher Ali Madani Pradeep Goel Kourosh Mohammadi 《Arabian Journal of Geosciences》2016,9(11):582
The recently developed SWATDRAIN model was employed to assess the impact of controlled drainage on the water table dynamics, subsurface drainage, and surface runoff in an agricultural watershed in Ontario, Canada. Controlled drainage was defined with a depth of 1.0 m to restrict flow at the drain outlet to maintain the water table at 0.5 m below the surface level during the winter (November–April) and at 0.6 m during the summer (June–August) months. The effects of the absence, or implementation, of drainage water management were predicted for the 3-year period of 1991–1993. Implementing controlled drainage resulted in a 16 % reduction in the mean annual drain flow, while increasing surface runoff by as much as 71 %. This indicates that overall watershed hydrology could be significantly impacted by the implementation of controlled drainage. This research demonstrates the SWATDRAIN model’s ability to predict the controlled drainage in small agricultural watersheds. 相似文献
4.
Peter Worsley 《Geology Today》2013,29(4):144-149
The Sulham Gap is a distinctive valley in the English county of Berkshire. Following a late Devensian drainage diversion, the Sulham Gap lowland was left as a poorly drained former floodplain. A major flood, with an unprecedented magnitude, occurred in July 2007 sourced primarily from the River Pang which enters the gap on the western side. Its physical impact was exacerbated by: 1, medieval extraction of postglacial peat; and 2, the building of leats for watermills. The flood water drained across the topographically lower drainage network of the diminutive Sulham Brook to the eastern side of the gap and backed-up behind culverts beneath both a road and a railway embankment resulting in some 140 homes being inundated. 相似文献
5.
Reza Ghasemizadeh Xue Yu Christoph Butscher Ingrid Y. Padilla Akram Alshawabkeh 《Hydrogeology Journal》2016,24(6):1463-1478
In northern Puerto Rico (USA), subsurface conduit networks with unknown characteristics, and surface features such as springs, rivers, lagoons and wetlands, drain the coastal karst aquifers. In this study, drain lines connecting sinkholes and springs are used to improve the developed regional model by simulating the drainage effects of conduit networks. Implemented in an equivalent porous media (EPM) approach, the model with drains is able to roughly reproduce the spring discharge hydrographs in response to rainfall. Hydraulic conductivities are found to be scale dependent and significantly increase with higher test radius, indicating scale dependency of the EPM approach. Similar to other karst regions in the world, hydraulic gradients are steeper where the transmissivity is lower approaching the coastline. This study enhances current understanding of the complex flow patterns in karst aquifers and suggests that using a drainage feature improves modeling results where available data on conduit characteristics are minimal. 相似文献
6.
复杂荷载作用下考虑下卧层三维渗流的未打穿竖井地基固结分析 总被引：2，自引：0，他引：2
针对任意复杂变荷载作用下未打穿的竖井地基,通过在竖井底面以下土层中设置虚拟竖井,使其能够合理考虑下卧层土体三维渗流问题,运用Laplace变换,求得频域内竖井地基的固结解。通过Laplace逆变换,得到了任意荷载作用下竖井地基的平均固结度、孔压消散曲线、沉降曲线。结合具体算例,对影响竖井地基固结的主要影响因素进行了详细分析,并将现有未打穿竖井地基平均固结度近似计算方法的精度和适用的范围进行了对比,得到了一些有益于工程实践的结论。 相似文献
7.
Manuel Helbig Julia Boike Moritz Langer Peter Schreiber Benjamin R. K. Runkle Lars Kutzbach 《Hydrogeology Journal》2013,21(1):133-147
The summer water balance of a typical Siberian polygonal tundra catchment is investigated in order to identify the spatial and temporal dynamics of its main hydrological processes. The results show that, besides precipitation and evapotranspiration, lateral flow considerably influences the site-specific hydrological conditions. The prominent microtopography of the polygonal tundra strongly controls lateral flow and storage behaviour of the investigated catchment. Intact rims of low-centred polygons build hydrological barriers, which release storage water later in summer than polygons with degraded rims and troughs above degraded ice wedges. The barrier function of rims is strongly controlled by soil thaw, which opens new subsurface flow paths and increases subsurface hydrological connectivity. Therefore, soil thaw dynamics determine the magnitude and timing of subsurface outflow and the redistribution of storage within the catchment. Hydraulic conductivities in the elevated polygonal rims sharply decrease with the transition from organic to mineral layers. This interface causes a rapid shallow subsurface drainage of rainwater towards the depressed polygon centres and troughs. The re-release of storage water from the centres through deeper and less conductive layers helps maintain a high water table in the surface drainage network of troughs throughout the summer. 相似文献
8.
Bahram Nourani Farzin Salmasi Akram Abbaspour Behrooz Oghati Bakhshayesh 《Geotechnical and Geological Engineering》2017,35(2):799-808
The seepage beneath a concrete dam causes an upward force acting to the dam foundation, known as uplift. Previous literatures show that implementation of drainage wells in gravity dam foundations causes a reduction in uplift forces. The main aim of these wells is to drain excess seepage flow bypassed from the cutoff wall and to reduce the uplift force. The location of the drains in the foundation plays a key role in reducing the pressure. In the present study, effect of the location of drain pipes from the upstream face of the dam (s), space among them (n) and drain’s diameter (d) in uplift force reduction is investigated. The processes of the study have been performed by the Seep/w software based on the finite element method. Results show that the use of a drain system reduced the uplift forces developed beneath the floor of the structure. If the drain is located close to the face of the dam, it may not be effective in reducing the uplift. On the other hand, shifting it too much away from the upstream face of the dam will lead to increased total uplift. It is, therefore, desirable to find out the location of the drain such that the total uplift is optimum. Optimum location of the vertical drains is not fixed, and by increasing vertical drains distances from each other and also decreasing drain diameter, optimum location would be shifted to the downstream. For example introduction of system of pipe drains to the floor of gravity dams reduced the uplift force acting on the floor by up to 80% for d/l = 0.0004, n/l = 0.024 and s/l = 0.08. This reduction in uplift becomes up to 65% for d/l = 0.0004, n/l = 0.048 and s/l = 0.12. The best location of the drain is such that the total uplift is minimum and this is presented in both design charts and algebraic equations in this study. 相似文献
9.
针对新技术热排水固结法,采用非等温管道流模拟竖井中U型导热管的传热过程,考虑温度对竖井扰动区和未扰动区渗透性的影响,在COMSOL Multiphysics有限元软件中进行二次开发,建立了竖井地基热排水固结法的有限元模型。以热排水固结软基处理原型试验为例,重点分析了模型耦合、部分耦合和不耦合情况下软土地基的固结度。结果表明,相对于传统排水固结法的不耦合模型,部分耦合模型下因温度产生的孔压增量延缓了地基固结的发展,固结速率有所减慢;耦合模型下温度虽也产生一定的孔压增量,但温度有效地改善了竖井涂抹区土的渗透特性,地基的固结速率加快,固结周期缩短,与试验结果一致。 相似文献
10.
Landslides in Jordan have caused numerous problems during the past 40 years. The most critical slides occurred during the period of 1991/1992 after exceptional heavy rain and snowfall. Many disastrous landslides occurred along the newly reconstructed international highway that links Amman, Jerash and Irbid. Causes for these slides are attributed mainly to the lack of a comprehensive overview and geotechnical understanding of the problem.Many investigators have been interested in this problem of finding an adequate solution to such landslides in Jordan either by using theoretical analysis or by using computer software to solve the slope instability problems. A detailed study was conducted at the Jordan University of Science and Technology to investigate the potential causes and measures for this problem. Seven landslides along the mountainous section of this international highway were reviewed. One of these landslides was thoroughly investigated using a three-dimensional computer program called JUST-SLOPE introduced at the Jordan University of Science and Technology campus. Results of this study indicate that landslides at this site could have been predicted had this technique been applied prior to the occurrence of this slide. 相似文献
11.
Mengmeng Lu Scott W. Sloan Buddhima Indraratna Hongwen Jing Kanghe Xie 《国际地质力学数值与分析法杂志》2016,40(11):1623-1640
Various analytical theories of consolidation for soils with vertical drains have been proposed in the past. Most conventional theories are based on a cylindrical unit cell that contains only a single vertical drain. This paper described a new analytical model where a vertical drain located at the centre (the ‘inner vertical drain’) and is surrounded by two or three vertical drains (the ‘outer vertical drains’), the number of which depends on whether the configuration is triangular or rectangular. Both types of drains are combined into a cylindrical unit cell, and the water is assumed to flow both inwards to the inner vertical drain and outwards to the outer vertical drains distributed around the circumference. The outer radial boundary of the unit cell is regarded as a permeable boundary, with a drainage capacity of two or three separate vertical drains for triangular and rectangular configurations, respectively. The smear effects and the drainage resistances for both the inner and outer vertical drains are considered in the analysis as well. In this way, the equations governing the consolidation process with multiple vertical drains are derived, and the corresponding analytical solutions are obtained for instantaneously loading, ramp loading and multi‐stage of instantaneously loading and multi‐stage of ramp loading. The present solutions are finally compared with several conventional solutions for a single vertical drain in the literature. The results show that the present model predicts the same average degree of consolidation as conventional models do, which verifies the correctness of this new model. Finally, the settlement predicted by the present solution is compared with the measured settlement from a field test at the Port of Brisbane, Australia, which shows a good agreement between them. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
12.
Construction techniques for the Taklamakan Desert Highway: research on the construction materials and the results of field tests 总被引：1，自引：0，他引：1
After conducting many laboratory and field experiments, several key technical issues related to the construction of China’s
Taklamakan Desert Highway have been satisfactorily resolved. In particular, considerable progress has been made on the dry
compaction of a sand sub-base, road design parameters, the creation of a structure that combines a sub-grade and asphalt pavement,
analysis of the stability of a sand sub-base strengthened with geotextiles, and on the development of a complete set of construction
techniques. The achievements of this research were successfully applied for the first time in the Taklamakan Desert, where
the environmental conditions are extremely harsh. The results suggest that the construction of this highway was economical
and that the simple construction methods produced a reliable highway. The resulting highway is believed to be the world’s
first long-distance graded highway running through a huge desert with migrating dunes. 相似文献
13.
The paper explores the impact of hydrology on the Port-Harcourt–Patani-Warri Road. It reviews the hydrometeorological, drainage
and terrain peculiarities of the area against the backdrop of the design, alignment and performance of the road. The paper
ascribes the poor performance of the road to:
1. The southeast-northwest orientation of the road in a region with predominately northeast-southwest surface and subsurface
flow, in which the road acts like a dam;
2. The inferior construction aggregate composition;
3. Changes in pavement condition due to interaction of local road aggregates with water.
Received: 21 September 1998 · Accepted: 16 November 1999 相似文献
14.
Muheeb M. Awawdeh Mohammad A. ElMughrabi Mohammad Y. Atallah 《Environmental Earth Sciences》2018,77(21):732
Road instability along the Jerash–Amman highway was assessed using the weighted overlay method in Geographic Information System environment. The landslide susceptibility map was developed from nine contributing parameters. The map of landslide susceptibility was classified into five zones: very low (very stable), low (stable), moderate (moderately stable), high (unstable), and very high (highly unstable). The very high susceptibility and high susceptibility zones covered 15.14% and 31.81% of the study area, respectively. The main factors that made most parts of study area prone to landslides include excessive drainage channels, road cuts, and unfavorable rock strata such as marl and friable sandstone intercalated with clay and highly fractured limestone. Fracture zones are a major player in land instability. The moderate and high susceptibility zones are the most common in urban (e.g., Salhoub and Gaza camp) and agricultural areas. About 34% of the urban areas and 28.82% of the agricultural areas are characterized by the high susceptibility zone. Twenty percent of the Jerash–Amman highway length and 58% of the overall highway length are located in the very high susceptibility zone. The landslide susceptibility map was validated by the recorded landslides. More than 80 of the inventoried landslides are in unstable zones, which indicate that the selected causative factors are relevant and the model performs properly. 相似文献
15.
Mohanned S. Al-Sheriadeh Abdallah I. Husein Malkawi Ashraf Al-Hamdan Nabil S. Abderahman 《Engineering Geology》2000,56(3-4):361-372
With a capacity of 86 MCM, King Talal Reservoir is considered a major water supply in Jordan. It was built exclusively to irrigate the land in the Jordan Valley. Unexpectedly, the design capacity of the reservoir was confronted by the elevated sediment inflows during and after the construction of the Irbid–Amman Highway in 1987. Since then the annual sediment inflow measured at the mouth of the reservoir was higher than expected in a similar year. Notably, the over-wet season of 1991/2, as a result of six major landslides along the highway, registered the highest sediment inflow into the reservoir. In the present work the fractional contribution of these landslides to total sediment yield at the reservoir was evaluated. The evaluation was made by applying the well-known erosion model, AGNPS (Young et al., USDA Conservation Research Report 35, 1987). To calibrate the model, it was successively applied from 1980/1 to 1990/1 on the measured sediment data before the occurrence of landslides. With a slight tune-up of some of the King Talal watershed erosion variables, fairly good agreement was obtained in some years. However, the disagreement noticed in other years might be attributed to some conservation measures practised in the watershed. Because the serious landslides occurred in the wet season of 1991/2, the model was run for the two scenarios in this year: with and without landslides. The difference in results represents the contribution of landslides to sediment yield at the reservoir. It is concluded, based on these results, that landslides, if continued without control, will definitely jeopardize the design capacity of the reservoir. 相似文献
16.
The disastrous flood of 1998 was a result of excessiverainfall all over the catchment areas of the major rivers of Bangladesh. Dhaka City, which is surroundedby rivers on all sides, was seriously affected despite the completion of Phase I of the Dhaka IntegratedFlood Protection Project (DIFPP). Water entered into the protected part of the city throughhydraulic leakage such as buried sewerage pipes, breached and incomplete floodwalls, ungated culverts andinoperative regulators. The drainage network and retention ponds of the city were found to be in poorconditions and capacities of the pumping stations were found inadequate. There was a serious lack of coordinationbetween the agencies responsible for flood protection and drainage of the city. These issues must beaddressed to achieve long-term flood mitigation. In addition, feedback from both the experts andgeneral public indicated that completion of Phase II of DIFPP was essential to bring the eastern part ofthe city under flood protection. Other structural measures suggested in this paper include installing andmaintaining adequate drainage and pumping capacity and timely operation of regulators. This studyalso suggests a set of non-structural measures for flood mitigation that include protectingthe retention ponds, raising public awareness on maintaining the city drains, introducing landzoning and flood proofing in the eastern part of Dhaka, and stream lining institutional bottlenecks. 相似文献
17.
Acid mine drainage (AMD) from abandoned underground mines significantly impairs water quality in the Jones Branch watershed
in McCreary Co., Kentucky, USA. A 1022-m2 surface-flow wetland was constructed in 1989 to reduce the AMD effects, however, the system failed after six months due to
insufficient utilization of the treatment area, inadequate alkalinity production and metal overloading. In an attempt to improve
treatment efficiencies, a renovation project was designed incorporating two anoxic limestone drains (ALDs) and a series of
anaerobic subsurface drains that promote vertical flow of mine water through a successive alkalinity producing system (SAPS)
of limestone beds overlain by organic compost. Analytical results from the 19-month post-renovation period are very encouraging.
Mean iron concentrations have decreased from 787 to 39 mg l–1, pH increased from 3.38 to 6.46 and acidity has been reduced from 2244 to 199 mg l–1 (CaCO3 equivalent). Mass removal rates averaged 98% for Al, 95% for Fe, 94% for acidity, 55% for sulfate and 49% for Mn during the
study period. The results indicate that increased alkalinity production from limestone dissolution and longer residence time
have contributed to sufficient buffering and metal retention. The combination of ALDs and SAPS technologies used in the renovation
and the sequence in which they were implemented within the wetland system proved to be an adequate and very promising design
for the treatment of this and other sources of high metal load AMD.
Received: 29 June 1998 · Accepted: 15 September 1998 相似文献
18.
In 1986, the Malaysian Highway Authority constructed a series of trial embankments on the Muar Plain (soft marine clay) with the aim of evaluating the effectiveness of various ground improvement techniques. This study investigates the effect of two such ground improvement schemes: (a) preloading of foundation with surface geogrids and synthetic vertical drains and (b) sand compaction piles. The paper is focused on the finite element analysis of settlements and lateral displacements of the soft foundation. In scheme (a), the numerical predictions are compared with the field measurements. In scheme (b), only the numerical analysis is presented and discussed in the absence of reliable measurements due to the malfunctioning of the electronic extensometer and inclinometer system during embankment construction. The current analysis employs critical state soil mechanics, and the deformations are predicted on the basis of the fully coupled (Biot) consolidation model. The vertical drain pattern is converted to equivalent drain walls to enable plane strain modelling, and the geogrids are simulated by linear interface slip elements. The effect of sand compaction piles is investigated considering both ideal drains and non-ideal drains, as well as varying the pile stiffness. © 1997 by John Wiley & Sons, Ltd. 相似文献
19.
速流结构防治泥石流的理论及应用 总被引：17，自引：4，他引：17
作为一种公路沿线发育的地质灾害，泥石流是路基、路面及相关建、构筑物最强烈的毁损动力。为了防治泥石流公路灾害，作者开发了速流结构。该结构由汇流槽和速流槽组成。其中汇流槽的侧墙长度、高度’、厚度等参数通过泥石流沟形态及其冲击力综合确定；而速流槽的宽度、侧墙及纵横断面则由泥石流排泄量、流速、锁固桩及流体性质综合确定。根据公路穿越速流结构的方式，将速流结构分为底越式和顶越式2种。速流结构对于解决具有大冲大淤特性的冲淤变动型沟谷泥石流灾害具有重要应用价值。据此可以确保穿越泥石流沟的公路构、建筑物的安全与稳定．确保公路交通有序进行。此外，文章对速流结构的一些子结构，如速流槽侧墙及锁固桩进行了力学分析。位于川西南西昌-木里干线公路的平川泥石流属于典型的冲淤变动型沟谷泥石流。该沟长度8．2km，沟床平均比降0．181，平均流速9．0m／s，沉积区宽度500m左右。为了确保该段公路交通的有序进行，作者干1999年实施了平川泥石流速流结构。通过2000年以来的研究及现场测试，显示了该防治结构的优越性。但是，作为一种特殊的水工结构，泥石流对速流结构的磨蚀作用是比较强烈的。因此，开展速流结构的抗冲、抗撞研究是进一步研究具有重要价值。 相似文献
20.
M. M. Matinzadeh J. Abedi Koupai A. Sadeghi-Lari H. Nozari M. Shayannejad 《International Journal of Environmental Science and Technology》2017,14(3):563-576
The excessive loss of soil nitrogen through drainage losses causes different environmental problems. The depth and spacing drain of drains play an important role in the quality and quantity of discharged drainage into the environment. In this paper, a simple but comprehensive model using system dynamic approach for water cycle and nitrogen dynamics was used to simulate the effect of drain depth and spacing on nitrate and ammonium losses in a sugarcane agro-industrial company. Twenty-four scenarios were modeled including the combination of four different drain depths and six drain spacing to compare the effect of drain depth and spacing on the nitrogen uptake by plant, denitrification, net mineralization, the amount of ammonium losses through runoff, nitrate and ammonium losses through drainage water, the sum of excessive water, the stress day index and the relative yield. The results indicated that optimal drainage system density is obtained in the depth of 1.1 m and spacing of 80 m, in a way that the total drainage losses would be reduced up to an acceptable level. The optimum designing of the drainage systems according to environmental criteria can control nitrogen pollution load at farm level and can therefore have appropriate results both in terms of economic and environmental considerations. 相似文献