| dc.description.abstract | Åseberget is a low-lying hill and planned building site in Kungälv, southwestern Sweden. The
potential contaminants and complications of construction work are of a great concern as the area
has previously been utilized as a landfill. A planned building site requires careful examination of
potential obstacles and uncertainties before any construction work is initiated. Earlier field
measurements have shown that the area is contaminated with gas; there are significant levels of
methane gas that could pose a risk of explosivity if they reach 5-15% in air. The filling material
of the site is generally unknown. However, through several field investigations, it appears to
consist mostly of masses of soil such as clay. The purpose of this report is to characterize
Åseberget, investigate the field data of gas levels, discuss building technical solutions, and try to
evaluate the suitability of the area for construction.
The method used in this report was mainly through the study of literature by reading field reports
from earlier investigations of Åseberget. As well as other relevant literature sources to find
adequate data and information about building technical solutions, methane gas, landfills, and so
on. Another approach was to assemble the field data and create maps showing the measured
variation of gas levels across the area. The result shows that the methane gas levels are
fluctuating and that it can range from 0% up to 100% in different locations across the landfill.
The source of the gas is thought to derive from inclusions of organic material such as humus,
peat, grass, and moss. The gas is assessed to be located in pockets in the ground and eventually
will completely mitigate over time, but development of the area will most likely cause new
pathways of gas migration and potential accumulation inside temporary construction sites and
future permanent residential buildings. The site will be buildable if the potential risks of
accumulation of methane gas are considered and included in the plans of development. The most
recommended and utilized building technical solution for gas-contaminated land is sub-slab
depressurization as well as installing impermeable plastic membranes into the concrete or timber
foundation. Nevertheless, the biggest risk lies in the construction work itself, which creates new
gas migration pathways, potential spaces for accumulation and ignition sources. This therefore
requires careful planning and consideration of the working conditions to prevent any hazards. | en_US |
