جستجوی مقالات مرتبط با کلیدواژه "stabilization" در نشریات گروه "آبخیزداری، بیابان، محیط زیست، مرتع"

In this study, plant samples were identified using available scientific sources and by examining various plant characteristics including: density, frequency, canopy status, roots and rhizomes, amount of litter produced, vegetative form, propagation method and longevity, priority plants were classified in order to stabilize and protect the marls. According to the results, 34, 59 and 61 species, respectively, in the first to third priority in order to stabilize and conservation marls in these watershed were introduced. It is necessary to reproduce and establish bush, shrub, tree, forb and perennial grass species, and annual grass and forb species in these lands, respectively. Also, considering the botanical characteristics and natural characteristics of the region and emphasizing that in addition to the issue of erodibility and sediment production, marl lands are mainly low permeability and insufficient moisture for the establishment and growth of plants; It is recommended for the establishment and reproduction of species such as: Astragalus susianus Boiss.، Astragalus gossypinus Fisch. and Artemisia Aucheri Boiss. Take action in the areas covered by marl in this watershed. Because with the management and establishment of these species, in addition to soil conservation, the opportunity to reproduce and preserve these valuable plant species will be provided.

 Due to the detrimental consequences of the application of stabilizers such as mulch and other protectives on the soil surface, including the wafting of bad smell, blackening of the ground, increasing thermal coefficient, warming of the whole area, and even destruction of plants and their unsustainability in nature, wide use of such stabilizers could not be considered as a useful solution to control wind erosion. Therefore, to solve the problem of sandstorms in Iran and get the desertschr('39') soil stabilized, this study proposes that deserts be coated with non-erodible materials (e.g., gravel, sandblasting, etc.)

Based on the purpose of this study, the effect of gravel cover with 30%, 50%, and 75% coverage on the sandblasting rate of MontazerQaem -TaleHamid desert was investigated using the wind tunnel. To investigate the effect of different gravel coatings on the sand particle transport rate, first, a sand sample was gathered from the Talle-Hamid area in Tabas, located 209 km off the Bafgh Railway, at 55/89 latitude and 32/93 longitude degrees, respectively, and the particle density of sand particles size was measured using standard ASTM D854-02. Its amount was found to be 2724 kg/m3. In the next stages, dry aggregation of sand particle size was first extracted from different parts of the MontazerQaem-Talle-Hamid track. According to the ASHTO T27 standard, at least 500 gr random fine sample particles should be collected from each site to sieve. Four samples were collected from sites that were 209, 213, 217, 222, and 222.7 km off Tabas. Having enumerated Standard-sized sieved particles, we used a vibrating machine to shake different particle diameters for at least 15 minutes. Furthermore, scales with a minimum accuracy of 0.01gr were used to weigh particles of different diameters. According to the standard of reconstitution for fine particles such as sand, the minimum sample size for sieving is 300gr, and the sample should be dried at 110 ° C in a three-stage oven. Then, these particleschr('39') transportation rate was measured at different wind speeds for uncovered gravel samples.

Initially, by increasing the wind speed from 1 m/s to 8 m/s, it was found that the particlechr('39')s creeping movement started at 6.9 m/s and its creeping speed was 6.9 m/s. The index sample was then placed in the wind tunnel for 5 minutes at different speeds of 9.9, 12.4, 17.2, and 22 m/s, and sand particle transportation was determined. It was also found that wind erosion increased by increasing wind speed polynomials. Subsequently, sands with 30-50% and 75% gravel cover were inserted into the wind tunnel for 5 minutes at wind speeds of 10.5, 15.7, and 22.9 m/s. Having determined the rate of wind erosion, we observed that the wind erosion rate decreased with an increasing percentage of gravel cover at a certain speed. We also found that the greatest effect on decreasing wind erosion rate occurred at wind speed 22.9 m/s, with the reduction percentage of erosion being 67.5%. The study results showed that the wind erosion rate decreased with an increasing rate of gravel cover at a certain speed, and the highest effect of graved on reducing wind erosion was reported for gravel cover of 75%. Therefore, covering the surface of a sandy desert with non-corrosive materials such as sand or gravel could be a practical solution for preventing wind erosion.

The effects of non-erodible coating or gravel on the rate of sand particle erosion were investigated via the wind tunnel, the results of which showed that the samples with gravel cover were effective in reducing wind erosion of sand particles. The greatest reduction in wind erosion rate was reported for the sites covered by 75% gravel. According to research conducted in the Chinese deserts, gravel cover with eroding sand particles and reducing wind velocity at the sand surface could well improve erosive sand levels. The present study also showed that at 22.9 m/s wind speed and 75% gravel cover, the erosion rate decreased by 67.5%. Therefore, to reduce the effects of sandstorms in Iran and stabilize the sandy desert area, non-erodible coating such as gravel would be recommended instead of mulch.

Abstract: Wind erosion phenomenon is considered as one of the main processes of land degradation in arid and semi-arid regions. The emission of dust and motion of sand by wind power is known as one of the main causes of the desertification process, resulting in the conversion of agricultural areas to landfills and the creation of sand coverage on them. The sand dunes, due to insufficient moisture and lack of appropriate plant cover, have little adhesion and are susceptible to erosion of the wind, thus stabilizing and preventing their development is necessary. One of the common methods of controlling sand is mulching on a surface of sandy hills, where mulch is divided into two groups of oil and non-oil. Recently, paying attention to the problem of environmental degradation by the oil mulch and the high cost of using this type of mulch, has enabled the country's scientific and research centers to investigate the changes in the type and methods of mulching. In the present study, mulches have been introduced from the point of view of their mechanism of action in stabilizing sandy soils and recognizing the disadvantages and the benefits of using mulches. The results of this study indicate that although the traditional use of oil mulch has been an important step in the implementation of sand stabilization over the years, due to its many disadvantages and problems, including the high cost of using this type of mulch and the necessity of using the machine Heavy machinery in field operations, environmental and health problems with this type of mulch and, ultimately, the huge losses that our economic resources each year suffer from wind erosion, Today, it is suggested that, while using oil mulch in very urgent cases, research and promotion of the use of biodegradable mulch using various titles should be used in order to improve the properties and the quality of these biohazardous mulches in the future, production costs It was reduced to an acceptable level.

Check dams are constructions which could be utilized with the aim of not only decrease of river slope and flood velocity; but also، control of river bed erosion. Furthermore، ultimate slope plays an important role in determination of check dam''s distances. In this Study، a survey and investigation has been done on Goush and Bahreh catchments، Kortian، Kameh and Dasht basins which are located on upstream of Kardeh، Torogh، Shahid Yaghubi and Golestan dams respectively. Consequently، the performance of constructed check dams in term of stability، sedimentation and slope stabilization has been investigated. Moreover، longitudinal section profile، ultimate slope، location، distances and height of dames with acceptable performance about upstream ultimate slope has been measured. Meanwhile، characteristics related to bed aggregates has been sampled and determined. Then، with the measure of dimensions regarding the ultimate slope، some equations which were based on primary slope of river direction has been developed. With the comparison between mentioned equations and the ones which were suggested with other researchers، we argued that one equation that has been defined just based on channel slope could be obviously accepted and the reason originated from the fact that not only this equation did not require any sampling data about river bed aggregates; but also، could result accurate results.

In order to assess the stability of slopes of the proposed sites for the construction of acomposting plant, field studies, laboratory experiments, analysis of geologicalengineering and geotechnical data of the site location were performed. Results ofstudies indicate the existence of the phenomenon of occurrences of old landslides at thesite. After collecting data, and analyzing the factors affecting the recurrence of landslideusing both limit equilibrium stability analysis and Slope / w software, Factor of Safety(FOS) and probability of occurrences (FOS<1) in various conditions based on Bishopmethod were calculated. Based on the results, the lowest FOS values under saturatedconditions and dynamic loading of the probability of earthquakes was found to be(pseudo static analysis) equal to 0.676 which shows in this situation slope isunconditionally unstable. Highest FOS in static conditions was equivalent to 1.30 whereit is applied to drainage would increase to 1.50. Accordingly, construction of deepdrains and drainage wells is suggested to collect groundwater and subsurface flows inorder to reduce degree of saturation and increase FOS and stability while providingsafety would be economically justified.