Stability of expansive cement grout borehole seals emplaced in the vicinity of underground radioactive waste repositories

An expansive cementitious borehole plug emplaced in an underground opening in the vicinity of an underground nuclear waste repository may generate radial stresses on the walls of the opening due to an axial stress applied to the borehole plug and due to plug swelling. As these radial stresses may lead to the tensile fracturing of the rock, minimizing or preferably eliminating tensile stresses in rock is particularly important to preserve waste containment. Presented in this paper are the theoretical radial (normal) stress distribution and tensile strength in a borehole plug-rock system due to combined axial, thermal and lateral loading, along with analyses of plug-rock mechanical interactions in regards to borehole stability against tensile fracturing.


Evaluation of a compacted bentonite/sand seal for underground waste repository isolation
Akgün, Haluk; AKTÜRK, ÖZGÜR (Springer Science and Business Media LLC, 2006-06-01)
This study investigates the performance of an optimum compacted bentonite/sand mixture seal for the isolation of underground waste repositories. Engineering geological tests such as compaction, flow, swelling, mechanical and shear strength tests have been conducted to select an optimum mixture and to recommend a stable bentonite/sand seal length-to-radius ratio (L/a) as far as the factor of safety (F) is concerned. The results of the compaction permeameter tests led to a recommendation to select an optimum ...
Contamination of the cement raw material in a quarry site by seawater intrusion, Darica-Turkey
Çamur, Mehmet Zeki (Springer Science and Business Media LLC, 2008-02-01)
The open pit mining nearby shoreline is planned to be extended into below sea level in order to use additional reserves of the cement raw material (marl). The raw material is currently contaminated by seawater intrusion below a depth of 20 m up to the distance of 90 m from shoreline. Seawater intrusion related contamination of the material used for the cement production was investigated by means of diffusion process for the future two below sea level mining scenarios covering 43 years of period. According t...
An assessment of borehole sealing performance in a salt environment
Akgün, Haluk (Springer Science and Business Media LLC, 1997-05-01)
Design of plugs for abandonment of boreholes and shafts may be governed by the bond strength between the plug and host rock. This paper presents the results of push-out tests on cement grout plugs in salt. Two types of expandable cement grouts have been tested. The average interface shear strengths ranged from 2 to 12 MPa (290 to 1740 psi). Peak shear stresses at failure, assuming an elastic stress distribution along the interface, were up to eight times higher. Standard deviations commonly reached 20%. Dis...
Composite landfill liner design with Ankara clay, Turkey
Met, İlker; Akgün, Haluk (Springer Science and Business Media LLC, 2005-04-01)
This study presents an overview of the geotechnical properties of the clayey soils, referred to as "Ankara clay", at two sites of the Ankara region in an attempt to design a landfill profile composed of a high density polyethylene (HDPE) geomembrane/clay composite liner through the Hydrologic Evaluation of Landfill Performance (HELP) model and the Water Balance Method. The geotechnical properties of the landfill layers along with the water balance factors (i.e., evapotranspiration, precipitation, temperatur...
Shear strength of municipal solid waste for stability analyses
Stark, Timothy D.; Huvaj Sarıhan, Nejan; Li, Guocheng (Springer Science and Business Media LLC, 2009-06-01)
This paper investigates the shear strength of municipal solid waste (MSW) using the back analysis of failed waste slopes as well as field and laboratory test results. Shear strength of MSW is a function of many factors such as waste type, composition, compaction, daily cover, moisture conditions, age, decomposition, overburden pressure, etc. These factors together with non-standardized sampling methods, insufficient sample size to be representative of in situ conditions, and limited shear displacement or ax...
Citation Formats
H. Akgün, “Stability of expansive cement grout borehole seals emplaced in the vicinity of underground radioactive waste repositories,” ENVIRONMENTAL GEOLOGY, pp. 1167–1171, 2004, Accessed: 00, 2020. [Online]. Available: