Ground linear subsidence in Taleghan area of Eshtehard city; exploring the causes, consequents and recommendations

Category Engineering Geology
Group GSI.IR
Location The 24 Symposium of Geosciences
Holding Date 18 August 2007


The ground subsidence in Taleghan area in Eastern part of Eshtehard city has been shaped since the summer of 2005 and caused serious damages to the buildings. To investigate of subsidence and with keeping in mind the probability of existence a Qanat gallery under the area, the geophysical investigation has been made and existence of a buried Qanat gallery has been proven in a depth of 15 meters of ground surface. The hydrogeological and engineering geology studies evaluate thickness, Hydraulic Conductivity and Transmissivity the water saturated and unsaturated layer of alluvial aquifer. The lowering of piezometric level during 2000– 2004 estimated to be up to 5 meters and caused increase the effective stress in the study area. The probability of waste water entrance from industrial town of Eshtehard into Qanat of Eshtehard rolled out and the entrance of sewage water of buildings in Taleghan area into alluvial aquifer can not be the main cause of subsidence of buildings.

The geotechnical studies suggest the soils in the area (USCS Classification) belong to Lean Clay (CL), Fat Clay (CH) and Silty Sand (SM). The maximum soil settlement more than allowable settlements. Soils recognize to be dispersive to semi dispersive soil.

Shift the inhabitances of the area to safe place and changing the land use of the area with notice of existence of buried Qanat in the area are some of recommendations.

tags: QAZVIN