آب و فاضلاب (Jun 2023)
Simulation and Analysis of Land Subsidence Phenomenon Using Poroelasticity Theory (Case Study: Tehran-Shahriar Plain)
Abstract
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.
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