Jämförelse av beräknad och verklig grundvattensänkning vid vägportar
Present master of science thesis has been carried out at the Swedish Road Administration consulting services (Vägverket Konsult) in Karlstad. The purpose of the study is to investigate how well the calculated drawdown of the groundwater table predicts the actual drawdown when the road and railway gates at the studied sites are built. For this purpose the groundwater levels at the three bridges were measured during 6 months. The bridges in question are two railway bridges situated in Ölme and Ulvåker and one road bridge crossing a pedestrian and cycling path in Lidköping.In Ölme the calculated area of influence was smaller than the measured one. It differed up to 30 meters, i.e. 80 %.In Lidköping the calculated area of influence agreed well with the measured one, but the groundwater level that the calculations were made from was more than one meter too low.In Ulvåker the measured groundwater levels were influenced by other factors and no conclusions could be drawn.When calculating how the groundwater level is affected from road and railway bridge constructions it is important to make sure to measure the groundwater level before the construction is made so that the unaffected level is known. Moreover the radius of the well should be set to a value less than 0.5 meters. It is also important that the conductivity is investigated thoroughly especially for confined aquifers. When measuring groundwater levels the examiner must make sure to plan the distances and depths of the piezometer wells, when to perform the measurements and how to protect the water in the wells from freezing.