نتایج جستجو برای: considering drains depth and spacing
تعداد نتایج: 16853075 فیلتر نتایج به سال:
Life in central Iran depends on the Zayandehrood river, making the preservation of its quality important. Salinization and pollution of the flow as a result of different organic and inorganic pollutants create serious threats to the environment and to the agricultural activities in the region. Although the role of the main drains discharged into the Zayandehrood in changing its quality is well ...
This paper presents results from an extensive experimental study on hydraulic performance of new rectangular bridge deck drains developed by the Texas Department of Transportation (TxDOT) Bridge Division. It fits between the deck reinforcement with the top of the drain flush with the bridge surface and does not interfere with the structural connection of the bridge rail to the deck. Experiments...
apart from other aspects, desert is a natural environment and is one of the appealing terrestrial elements. putting its symbolic and fictional senses aside, the term “desert” bears mystic sense more than material sense. in addition to the worlds materialistic experiences, desert has attracted the attention of writers because it creates a kind of inner experience, which returns the individual in...
In the study, Drainmod model was used to compare measured water table depth fluctuations on the farm with those simulated by the model, also comparison of measured drainage outflow of the farm drains and model simulated was investigated. This study was made in a part of the Irrigation and Drainage Network of ABADAN Date palms. By statistical analysis of the measured and predicted water table de...
Abstract: In recent years deadly earthquakes in seismic areas have caused special concerns regarding liquefaction phenomenon by researchers and specialists. Excess pore water pressure in loose sediments may cause phenomena such as boiling, shearing strength and dynamic stiffness reduction and lateral movements cause difficulties. Many remedial methods such as soil replacement with proper materi...
mathematical simulation of flow toward drains is an important and indispensable stage in drainage design and management. many related models have been developed, but most of them simulate the saturated flow toward drains without a due consideration of the unsaturated zone. in this study, the two dimensional differential equation governing saturated and unsaturated flow in porous media is numeri...
this research has been taken among the students of high school in karaj city during the years 1391 and 1392. this is a survey research and data gathering is through questionnaires. studying the “an analysis of students’ tendency toward non-native reference groups in karaj”. the questionnaire was distributed among 260 of these students who were chosen through multi step cluster sampling. conside...
A piezometric head method is proposed to estimate the impermeable layer depth used in drain spacing formulae. The method was tested and compared with soil texture changes and the US Bureau of Reclamation (USBR, 1978) criterion of impermeable layer being one with hydraulic conductivity one tenth to one fifth that of the weighted hydraulic conductivity of the upper layers. The proposed method, wh...
Shallow-water environments typically include sediments containing thin or low-shear layers. Numerical treatments of these types of layers require finer depth grid spacing than is needed elsewhere in the domain. Thin layers require finer grids to fully sample effects due to elasticity within the layer. As shear wave speeds approach zero, the governing system becomes singular and fine-grid spacin...
This research was carried out to study the impacts of geomorphologic characteristics of claypan on land use and land degradation. Databank of the study area was constructed and digital terrain model of claypan was prepared. By using GIS techniques spatial distributions of the subsurface drainage network, sediment transportation index and wetness index were calculated. The results indicate tha...
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