TA654 : Numerical modeling of subsidence in Mashhad plain
Thesis > Central Library of Shahrood University > Civil & Architectural Engineering > PhD > 2021
Authors:
[Author], Reza Naderi[Supervisor]
Abstarct: The occurrence of subsidence has been in many plains of Iran caus many problems, including the destruction of roads, residential areas, antiquities, important centers, transportation infrastructure networks, transmission lines and transmission networks (water, oil and gas).Mashhad plain with northwest-southeast stretch is located between Binalood heights (west and southwest) and Hezar Masjid (hot hill in north and northeast).Extensive exploitation of groundwater resources in Mashhad plain has caused a sharp drop in groundwater level and land subsidence in a large area of Mashhad plain since the late 60s, so that the maximum annual subsidence rate in this plain of 24 cm per year, one of It has the highest annual sitting rate in the plains of the country.In the plain of Mashhad, as well as in the city, this phenomenon has occurred in the form of cracks in the walls of buildings and joints and cracks in roads and damage to wells.The main purpose of this study is to investigate the occurrence of subsidence in the eastern part of the plain in the Mashhad-Chenaran area, considering the spread of subsidence phenomenon due to extensive groundwater exploitation and its negative effects in the Mashhad plain.From the implementation of the model with the results of the meeting in reality, the amount of subsidence in the critical areas of the plain for several years (1397-1407) has been predicted.After collecting the required information, which includes groundwater level and geotechnical information such as texture and soil type, alluvial laxyer thickness, etc., software (plaxis 3d) has been used to achieve this goal.The results of the implementation of this model show the high degree of compliance of these results with the rate of subsidence in the study area in reality. Sitting in these areas according to the results of the model from 3 cm to 11/75 per year shows that in fact this amount is from at least 3 cm to 12 cm.Therefore, using the available information, subsidence for the most critical points of the plain is predicted for a decade later.Studies and results indicate that due to lack of rainfall between the 70s and 1400 AH compared to the 60s and the reduction of water reserves has led to excessive use of groundwater resources, a total decline of 33 years (from the water year 1363-64 Until 1395-96) Mashhad aquifer is 28/67 meters and the average annual drop of this period has been 0/87 meters.The amount of subsidence in supercritical areas has varied from at least 3 cm to a maximum of 17/7 cm per year.
Keywords:
#Keywords: Land subsidence #Mashhad plain #groundwater level dropse Keeping place: Central Library of Shahrood University
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