seyed habib mousavi jahromi

Indiscriminate extraction of underground water sources causes a drop in the water level and an increase in the stress on the soil particles, which leads to the subsidence of the earth's surface. Shahryar's critical plain has been affected by the phenomenon of subsidence for the past few years. The existence of vital arteries, economic, pilgrimage and military areas has turned it into a strategic area, which doubles the cost of the harmful consequences of subsidence. In this research, a new method is used to predict and analyze subsidence, under the title of Poroelasticity module of COMSOL software, which uses the simultaneous solution of equations related to fluid movement in porous media and mechanical deformation. The output of the numerical model was validated and compared between 2003 and 2019 at 24 points with the alignment observations, the Sentinel 1 radar interferometric images. The correlation coefficient of 0.97 indicates an acceptable correlation between the data values, the good matching of the interferometric images with the maps of the subsidence zones obtained from the software data and the approach of the squared values of the mean squared error and the efficiency coefficient towards zero and one was obtained. The general result of the finite element numerical modeling showed that the average rate of subsidence during the year 2031 due to the successive compression of the upper layers of the aquifer, with a lower rate, about 13.19 cm and in the places where the thickness of the fine-grained layers increased, He finds that it will reach 18.38 cm. Also, the range of changes in the underground water level in the period of time, the type of land and the number of geological units are among the factors affecting the subsidence pattern and rate.

Understanding the climate and providing safe water are two critical issues in discussing climate change and water scarcity and alarm for the future.  The purpose of this study is to evaluate the SPI drought index on the trend and duration of drought in the region and its effect on river discharge and reservoir volume of the dam.  Using climate model scenarios, this trend was extracted in the future from 2030 to 2050, and its impact in the future was estimated. Therefore, SWAT software for 1994 to 2012 was used for four hydrometric stations of Gachsar, Sierra_Kelvan, Sierra_Karaj, and Pol-e-Khoab to achieve and calibrate the results of the SUFI2 algorithm in SWAT-CUP environment with appropriate bandwidth and Nash coefficients of 0.54, 0.45, 0.72, and 0.58 respectively. Also, validations for the period 2013 to 2019 were extracted 0.34, 0.38, 0.5, and 0.44, respectively. According to the results, the climate change and drought index trend indicated a decrease in river flow and increased temperature, increasing evaporation from the dam reservoir's surface. In general, the volume of the dam reservoir has decreased by about 24 to 35% based on different scenarios.  On the other hand, considering the UNESCO IWRM guidelines, examining the evolutionary trend, and changing the flow rate, it was suggested that to plan the basin and implement important policies, crisis control of three social, economic, and environmental scenarios is seriously considered in the region.

In exploitation of low-quality water in arid and semi-arid regions, irrigation management is essential to increase water use efficiency. Determination of crop-water-salinity production function is an essential tool for proper irrigation management. In this study, the AquaCrop model was first evaluated by considering 4 soil and water salinity levels and 4 deficit irrigation levels for the major cereal crops including wheat, barley, and corn in Qazvin Plain. The results showed that the coefficients of determination for wheat, barley, and corn yield were 0.97, 0.86 and 0.91, respectively. Therefore, the model can evaluate the performance in salinity and deficit irrigation conditions with a good approximation. To determine the optimal production functions of each crop, the results of the plant model were compared with three models of linear and nonlinear regression, and artificial neural network. The neural network model was able to estimate the performance compared to the AquaCrop model with lower error and higher correlation (0.99). These values in the linear function for wheat, barley, and corn were 0.98, 0.95, and 0.78 and in the nonlinear function as 0.92, 0.86 and 0.81, respectively. Also, the error calculated in the neural network method for wheat, barley, and maize was 40.16, 62.09, and 57.08 kg, respectively, which were less than the linear model by 75 %, 70 %, and 95 %; and less than the exponential model by 90 %, 85 %, and 93%, respectively. The best trained network for determining the water-salt production function for barley and wheat 5 Nero and for corn 7 Nero was introduced in the single layer structure. Sensitivity analysis on wheat and barley showed that this model had low sensitivity to irrigation and salinity parameters and only corn plant showed a moderate range sensitivity to salinity parameter.

A tunnel spillway is one of the spillway types in which a high free surface flow velocity is established. The pressure increases in concave vertical bends due to the rotational acceleration and the nature of irregularities in the turbulent flow. Physical models are the best tools to analyze this phenomenon. The number of the required physical models to cover all practical prototype condition analysis is so large that makes it impractical in terms of placement and costs. Therefore, the FLOW-3D software has been chosen to analyze and produce a database of turbulent flow in tunnels concave bends covering all possible practical alternatives. Various tunnels with different discharges and geometries have been simulated by this software. The numerical results were verified with the experimental ones of the constructed physical model of Alborz Dam tunnel spillway, and a satisfactory agreement was obtained. Dimensional analysis is used to group the involved variables of the problem into dimensionless parameters. These parameters are utilized in the artificial neural network simulation. The results showed a correlation coefficient R2=0.95 between the dimensionless parameters obtained by the Flow-3D software and those predicted by the neaural network which leads to the conclusion that the artificial neural network based on the database obtained by the turbulent flow modeling in this regard is a powerful tool for pressure prediction.

Triangular weirs (Triangular vanes) and footing are measures which causes to control the scour in outer bend and keep out scouring hole from the outer bend. In this study, the main purpose is to experimentally study the effect of using both footing and triangular weirs on sedimentation and erosion of a bed of flume bend under different flow conditions (Froude numbers 0.243, 0.262, 0.292 and 0.321). Tests were conducted using triangular weirs with distance of 8 times of the effective length installed at an angle of 30 degree from the upstream bank. Footing width and effective length of triangular weirs were selected one-fifth the width of the canal. The results showed that using footing combined with the triangular weirs caused to reduce maximum scour depth at the toe of weirs and prevent from its extension to outer bend. Using footing reduced 70 percent maximum scour depth at the toe of weirs. Moreover using footing combined with triangular weirs had a little effect on flow diversion from outer bank towards the center of flume. The results show that using footing along with triangular weirs increased 9 percent maximum scour depth of thalweg and did not change the thalweg distance from the outer bank.

Spur dike is one of the conventional structures in organizing and controlling erosion on the river side slopes. It causes the strong flows to be taken away of coastal and flow is guided towards river axis. On the other hand, changes in the flow pattern cause scour around spur dike. This study tries to evaluate the effect of increasing length in spur dike wing on the scour depth. Experiments were performed in the 90 degree meander with three different wing length, three different discharges and fixed depth. In addition L– shape spur dike was compared with ordinary spur dike. The result indicates that the scour depth and volume decreases with increase in wing length of spur dike. Comparing L-shape spur dike to ordinary spur dike show to be increase 3.25% up to 23.85%. Finally, an experimental predictor is presented for scouring in L-shape spur dike. This predictor has shown significant correlation with observation data in scour depth prediction.

One of the most important geotechnical issues is problematic soils (dispersive soils, expansive soils, collapsing soils, liquefying soils, soluble soils …) which may affect the constructing projects on these soils and may even cancel them [1]. In this research collapsing soils are studied. A sudden collapse of the land is called collapsing. It is because the strength of the bonding among soil particles no longer exists. Studies have shown the of these soils structure need to be improved before constructing any structures on them [2]. Improvement of these soils with various substances leads to different results. The effect of Polyurethane B with different combination percentages (0.5, 1, 1.5, 2, 3 and 5 weight percentage) on improving the structure of these soils were examined. Polyurethane B is one of the most common elastomerics in engineering which has numerous uses. It has unique characteristics such as high mechanical and wear resistance, flexibility in low temperature, high cutting potential and elasticity and resistance to absorbing water, oils and solvents. The most significant feature of these polymers is that a fixed structure is obtained after reaction. In this research, direct shear test was used with stress control. Vertical pressures of 54.5, 109 and 218 Kilopascals were applied out on specimens. In order to determine the collapsing rate, ASTM D 5333-03 standard criteria were used [3]. The sample was collected from Hamidiyeh Region near Ahvaz city. Atterberg limits, simple shear test and collapsible index experiments were carried out on the specimen to determine some of the physical and geotechnical features of the soil. The results are shown in Table 1. Collapsing tests revealed that by increasing the percentage of additive substance, collapsing index decreases. The value of collapsing index for 0.5, 1, 1.5, 2, 3 and 5 combination percentages were 45%, 58%, 75%, 86% and 92%. After conducting the direct shear test on the soil which was combined with Polyurethane B, it was concluded that the most shear strength can be obtained in 1% combination percentage. In this combination, the value of adhesion and angle of internal friction were increased 27% and 3%, respectively.

In this study the triangular flip bucket instead of circular shaped- with the same character but with different geometries- was studied. In this regard, the performance hydraulic overflow bucket with a bucket instead of the usual triangular shape, were compared in terms of energy dissipation. In this regard, the hydraulic performance triangular shaped bucket instead of the usual bucket, were compared in terms of energy dissipation.To achieve this goal, a physical model of the ogee spillway was built in the hydraulic physical models laboratory of Shahid Chamran University (SCU) and experiments were performed in 4 discharges that followed by four different Froude number. The for each discharge 3 tail-water depth were used to run experiments. The results showed that in comparison to the Total performance energy dissipation in triangle flip bucket with 45-degree angle insignificantly is better than cup flip bucket. For example, energy dissipation in Froude number 3.13 in the case of the free jet in the triangle and cup flip bucket respectively 66.4 and 54.8 percent. The lowest and most energy dissipation respectively related to triangle flip bucket with 22.5-degree angle and Triangle flip bucket with 45-degree angle with 7 cm approach channel. A comparison with results for the circular shaped bucket geometry indicates a favorable behavior of the novel bucket design.

Root system is effective on increase soil shear strength. This study investigates the root system of Tamarix trees on slope of riverbanks. Five trees (from TAMARIX species) which grow on the river beech were selected in a distance about one km on SAIMEREHRiver in IlamProvince. Circle profile trenching method was employed to obtain characteristics. Results show that the number of roots on upslope is about 22 percent more than downslope. For all diameters, the number of roots in upslope is more than downslope. The average of root diameters on downslope is bigger than upslope. Total root area on upslope is about 27.6 percent more than downslope. It is concluded that root system on riverbank is unsymmetrical and slope has effect on the root system. The number of roots and root area on upslope was more than downslope.