عنوان مقاله [English]
Ground subsidence in eastern part of Eshtehard, built on the alluvial deposits, is linear and gradual. Preparing geological map and profiles; we studied the structural geology of the area. The sort and situation of aquifer, evolution of ground water levels and hydrochemistry were studied and the presence of ancient channel was detected by geoelectric method. The geotechnical studies suggest that the soils in the area (USCS Classification) belong to Lean clay (CL), Fat Clay (CH) and Silty Sand (SM). The maximum soil settlement is more than allowable settlements and soils recognized to be dispersive to semi-dispersive soils. The possible entrance of waste water from Eshtehard Industrial town into Eshtehard Qanat, from septic wells and transfer water system seems to provide necessary moisture for dispersive soils and have caused the subsidence in the area. Hydrogeology of alluvial aquifer was evaluated and indicates a negative debit. Although the hydrographs of pizometric wells are not compensated but it display any role in linear subsidence. Soils prone to dispersion by infiltration of water from septic wells and urban water system and the presence of ancient Qantas hidden in the depth of 15 meters caused linear ground subsidence. The results of this study show the development of ancient Eshtehard city and the selection of new site was not carried out on the geotechnical basis. Therefore it is recommended that before constructing any projects, geotechnical studies are necessary.
Abbasnezhad, A., 2004- Karst sinkhole in Ekhtiarabad، NW Kerman, Geoscences، Vol. 12 No. 51-52, Geological Survey and Mineral Exploration of Iran.
American Society for Testing and Material, 2006- ASTM Standard, Section. 4, Vol. 04.08, Philadelphia, Pa.
Anvari, M. A. & Noroallahian, H., 2007- New approach to ground subsidence in Mashhad plain، 86 Geomatics Symposium، NCC.
Dadsetan, A., Rezaie, F., Sadeghi, A., Abdoli, M., Khandan, M., Jaferi, F., Rasedi, A. & Allahverdi, F., 2005- Ground linear subsidence in Taleghan area of Eshtehard city; exploring the causes، consequents and recommendations، Report of Geological Survey and Mineral Exploration of Iran, Tehran, Iran.
Dadsetan, A., Soltani, I. E. & Bolourchi, M. J., 2005- Preliminary investigation of sinkholes occurrence and their hazards in Kabudar Ahang، Famenin and Hamekasi plains (Hamedan Province)، Proceedings of the conference on hazards of sinkholes in karst terrains with emphsis on sinkholes of Hamedan, West Regional Water Authority.
Das, B. M., 1994- Advanced soil mechanics, Translated by Yazdchi M., University of Tehran press.
Das, B. M., 1998a- Principles of Foundation Engineering, Translated by Tahouni S., University of Tehran press, Vol. 2.
Das, B. M., 1998b- Principles of Geotechnical Engineering, Translated by Tahouni S., University of Tehran press, Vol. 1.
Rahnema, M. B. & Kazemi, A., 2006- Ground Subsidence due to groundwater level in Rafsanjan plain, First National Symposium of Irrigation and Drainage Networks Management, Kerman University.
Shemshaki, A. & Soltani, I. E., 2005- An outline causes of occurrence ground subsidence in SW Tehran, Geological Survey and Mineral Exploration of Iran.
Shemshaki, A., Bolourchi, M. J. & Ansari, F., 2005- Ground subsidence Evaluation in Tehran- Shahryar plain, Geological Survey and Mineral Exploration of Iran.
Tehran Regional Water Authority, 2003- Proposal Jastification report of respite impermissible of Eshtehard plain.
Tehran Regional Water Authority, 2005a- Geophysical prospecting of Eshtehard plain, Toseyeh Olom Zamin Co.
Tehran Regional Water Authority, 2005b- Semicomprehensive groundwater studies of Eshtehard plain, Vol. 1, 2 and 3, Abkhan Consulting Eng. Co.
Tehran Regional Water Authority, 2005c- Statistical report of surface and ground Water resources and utilities of the 7 studies area under coverage of General Office affairs of Tehran Province water, Eshtehard area, Lar Consulting Eng. Co.
USGS, 2000- Land Subsidence in United States, Fact Sheet- 165- 00, Internet Paper, Winter 2008.
Yousefi, M., 2000- Geological map of Eshtehard, Scale 1/100000, Geological Survey and Mineral Exploration of Iran.