Showing 3 results for Sinkhole
Volume 1, Issue 3 (3-2004)
Abstract
(paper pages 227-240) The Famenin,Kaboudar-Ahang,Ghahavand plains are located in the north of Hamedan province.The sediment thickness of thier aquifers is about 70-100 meters .In recent years, some big and dangerous sinkholes have been developed in this area.By the result of excavations that done in these plains and investigation of the sourrounded outcropped area,it was found that the bed rock of this area has been made of Oligo-miocen limestones. According to the field observation,the measuring of joints and fractures systems, stud of thin sections, characteristics of excavations, yield of wells, the results obtained by chemical experiments of water and the estimation of parameters such as saturation and stability indexes,the amount of free carbon dioxide and the primary pressure of carbon dioxide gas,it was concluded that the Karstification phenomenon was happened in the bed rock and the Endokarst structures exist in it. Thus,The exist of Endokarst in bed rock cased to wells have been had high yield and Sinkhole were made in these area.In order to avoid or reducing the occurrence rate of Sinkholes in this area, we should avoid digging new wells in the bed rock and should stop the pumping of wells which have been drilled in the bed rock and have high yield.
Volume 2, Issue 2 (3-2008)
Abstract
(Paper pages 473-492) One of the main reasons of destructions while happening earthquake and applying intense force is the brittle deformation of outer crust of the earth. Creep in the coastal sediments may happen by the virtue of existing cracks and fissures, unnatural movement and/or loss of the earth tolerance. This phenomenon in sandy areas may happen by increasing the pressure of gang ionic water and is called liquefaction. Studying the laboratory sample shows that the capability of liquefaction of sandy deposits can be decrease by flattening the land. One of the ways to improve the soil to increase the tolerance while applying dynamic loads is dynamic compaction. The design and usage of dynamic compaction usually depend on experiment. Dynamic compaction is an active design which needs a revision and method reformation in progress according to the reaction of the earth against the hit. In 12 parts of ship manufacturing and repairing factories bed in the Iran ship building and offshore industries complex co. located in 40km away in the west of Bandar Abbas, Dynamic compaction has been used to prevent liquefaction phenomenon. While performing of water in pressing step are happened that the following approaches are suggested: 1- To empty the water of sinkholes by a pump, 2- To perform dynamic compaction in two steps with regarding the adequate time between the steps of applying hits. and 3-Sludge taking in the surrounding areas and using large grain mixture and finally if needed to do deep drainage in a large area.
Ahmad Abbasnejad,
Volume 4, Issue 1 (11-2010)
Abstract
The previous studies underteaken in the region indicate that the Ekhtiarabad and Chah-Darya sinkholes have occurred as a result of dissolution of underground gypsum rocks. Hence, they represent the likelyhood of hidden and threatening caves in the region. The presence of gypsiferous formations having surficial karstic features attest to this supposition. So, in order to determine the possible dissolving sites which may contain caves, the electrical conductivity and evaporite dissolution index maps of Kerman-Baghin aquifier were prepared and matched with groundwater recharge and mobility conditions. Accordingly, four suspected hidden- cave sites were recognized which include a large area around Ekhtiarabad village (as the most suspected site), one spot at the northwest of Baghin Plain and two other areas (south of Baghin and south and southwest or Kabutarkhan). Based on the utilized hydrogeochemical criteria, these last two areas may contain hidden caves, but, due to unsuitable hydrodynamic conditions, the possibility seems weak.
