Borr- och arbetsmetoder vid instrumentering av fyllningsdammar
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
An embankment dam can be defined as a construction/barrier that impounds water. It’s main function is to collect water i.e. store water in the reservoir formed upstream of the dam. High safety standards is required with regard to the risk of damage to the dam or dam failure and the consequences it can bring to the environment, impact on buildings and facilities in the immediate area and along the river valley. As a part of the dam safety measures is the need to supplement the instrumentation of the dams. The aim off this supplement should at least reach the minimum level specified by RIDAS. However, what is not covered in RIDAS is how the installation of measuring equipment in embankment dams should be performed. Installation work is in many parts critical to the future quality of measurement results. Drilling in an embankment dam is a delicate job because use of water, air or any other drilling additives can cause damage to central parts of the dam that are subjected to unilateral water pressure. In this thesis, a literature and field study are conducted about the drilling methods that are suitable for embankment dams and those that are currently used for instrumentation of dams as well as how the work with these methods is carried out. The study shows that the choice of drilling method and drilling fluid is determined by the location of the borehole. The circulating media used to remove drill cuttings, affects soil material around the borehole to varying degrees. This largely depends on the permeability of the material that the drilling take place in. Air requires greater flow rate for efficient flushing of drill cuttings than water or any other type of drilling fluid. Higher flow rate gives a greater impact on the soil formation. The methods of choice when advancing a drill hole through an embankment to set casing should fall on one of those methods that adds as little pressure from circulating media as possible to the surrounding soil formation, such as OD- and DR-drilling. Eccentric/concentric methods can be very inappropriate to use in a filter zone which is sensitive to pressurization, but it may be appropriate to use to set casing in supporting fill that is not sensitive to pressurization. An exception is the Wassara method, that with its low flow rate, can be used in a filter zone. Both a drill engineer and a geotechnical engineer that works as a controller, must have knowledge of the construction of a dam, material, different zones and the risks associated with the drilling procedures of an embankment dam. This is to reduce the risk of dealing causing to the dam during execution of drilling work.
Place, publisher, year, edition, pages
2011. , 80 p.
Teknik, Fyllningsdammar, Borrmetoder
IdentifiersURN: urn:nbn:se:ltu:diva-57976Local ID: e9594dcd-075a-4430-956e-f0a1ce7c9cf0OAI: oai:DiVA.org:ltu-57976DiVA: diva2:1031364
Subject / course
Student thesis, at least 30 credits
Civil Engineering, master's level
Validerat; 20110607 (anonymous)2016-10-042016-10-04Bibliographically approved