Somayeh Taheri; Hasan Ahmadi; Jamal Ghodousi; ُSadat Feiznia; Shahram Khalighi Sigaroudi; Mohamad Hossein Ramesht
Abstract
subsidence in urban areas poses significant risks to infrastructure, including buildings, roads, railways, pipelines, sewage systems, and wells. Therefore, assessing its potential is crucial. This study models the subsidence risk in Karaj city using Geographic Information Systems (GIS) and the Weight ...
Read More
subsidence in urban areas poses significant risks to infrastructure, including buildings, roads, railways, pipelines, sewage systems, and wells. Therefore, assessing its potential is crucial. This study models the subsidence risk in Karaj city using Geographic Information Systems (GIS) and the Weight of Evidence (WoE) model. To achieve this, we created maps of factors influencing subsidence, such as slope, alluvial thickness, groundwater fluctuations, aquifer layering, particle size, and permeability. These maps were then compared with recorded subsidence data to determine the weight of each factor's influence. By integrating the effects of these factors, a Subsidence Index (SI) map was generated and categorized using the Success Rate Curve (SRC), identifying five sensitivity zones from very sensitive to very low sensitivity. The effectiveness of the WoE model was evaluated, revealing that the subsidence sensitivity prediction map covers 93.64% of actual occurrences. Results indicated that aquifer layering positively influences subsidence development, with the highest impact arising from alluvial deposits with good permeability and fine particles. This factor, with a weight of 3.72, demonstrates significant influence among all evaluated parameters. In terms of thickness, the most significant subsidence occurred in alluvial deposits exceeding 200 meters. Areas experiencing groundwater level declines of over half a meter annually markedly contributed to subsidence. Additionally, slopes of less than two degrees were identified as the most susceptible to subsidence. Thus, while many areas in Karaj are relatively safe, the threat is notably higher in the southern and southwestern parts, requiring special attention in urban management.
maryam mombeni; hamid reza asgari; ali Mohammadian Behbahani; Salman Zare; hossein yousefi
Abstract
One of the main challenges of land degradation management in arid and desert areas of Iran is the stabilization of sand as well as the control of dust; therefore the use of mulches, particularly eco-friendly mulch, is one of the ways to stabilize sand used. The purpose of this study was to investigate ...
Read More
One of the main challenges of land degradation management in arid and desert areas of Iran is the stabilization of sand as well as the control of dust; therefore the use of mulches, particularly eco-friendly mulch, is one of the ways to stabilize sand used. The purpose of this study was to investigate the possibility of using residues such as black liqueur and malass as mulch to stabilize the sand. To prepare the substrate for treatments in the laboratory environment, Rig Boland sandy of Kashan was used. Metal trays with dimensions of 100 × 30 × 2 cm were used for the experiments. For spraying of malass, black liquor and control treatments in a single layer and double layer of 2.5-liter sprinkler were applied and a completely randomized design with three replications was performed. To evaluate the performance of these materials, the shear strength, saturation, and dry strength and water permeability were measured and the data were analyzed by appropriate statistical software. In vitro results showed that the penetration resistance of molasses and black liqueur mulches were 9.8 and 7.8 kN/m2, respectively. These two types of mulch have significant differences with each other and with control (water) treatment. The highest penetration and shear strength were related to Malass treatment, which increased the penetration resistance by 9.8 times and the shear resistance by 14 times. The infiltration rate in one-layer liqueur mulch was significantly different compared to Malass and control (water) mulches, while the infiltration rate decreased with increasing thickness.
