The construction of the cutoff / diaphragm wall was completed at the Tétényi Street Station of the 4th line of the Metro
The works generating the most intensive noise have been completed at the Tétényi Street
The part of the construction of the station causing most of the inconveniences, that is, the construction of the cutoff / diaphragm wall was completed at the Tétényi Street Station at the end of October. At the beginning of November the construction works of the slab structure of the station began, to be followed by soil excavation, which will take place at a minimum level of traffic detours on the surface. The completion of the reinforced concrete structure of the station is scheduled next summer.
In the neighborhood of the Etele Square construction of the 4th line of the Metro takes place at three sites. On the site behind the Volán Terminal the construction of the launching shaft for the TBMs is underway; earthworks take place in the area of the future metro train depot , and the construction of the so called „forking structure ” that is, the tunnels leading to the metro train depot is also underway. On the Etele Street the substitution of sewers go along with the construction works. The launching shaft of the TBMs is scheduled to come on stream at the beginning of the next year.
The construction of metro stations at the Bocskai Street and Móricz Zsigmond Circus also proceeds as scheduled. The contractors completed 50 % of the construction of the cutoff / diaphragm wall at the Bocskai Street, and the works are expected to be completed by the middle of December. The completion of construction of the cutoff / diaphragm wall on the Móricz Zsigmond Circus is scheduled at the end of February 2007.
The construction of diaphragm walls begins at the Gellért Square at the beginning of the next year. This is some delay compared to the schedule but the contractors will do their best to make up for the arrears. The main reason of the delay is that the overflow shaft of the Gellért Bath was discovered during construction works and this structure did not figure on any of the earlier design drawings. This called for the modification of the preliminary design drawings and further delay was introduced at the licensing procedure.
The houses are covered
The technology of cutoff / diaphragm walls inevitably generates splashes of dirt, some of which may hit the neighboring houses. Mobile screens are built to protect the adjacent buildings from the spattering dirt. The contractors always place the mobile screens in front of buildings where the machines are currently working to assure that the least possible amount of contaminations reach the walls and windows of the buildings.
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About the technology of constructing cutoff / diaphragm walls
For the construction of most stations of the 4th line of the Metro the cutoff / diaphragm wall process is employed. This technology offers safe construction of the station structure while requiring traffic detours on the surface for the shortest possible time.
The cutoff / diaphragm wall is practically a reinforced concrete wall built vertically in the soil. The cutoff / diaphragm walls are the outer walls of the stations. The first step in the construction of the cutoff / diaphragm wall is the excavation of the “diaphragm” by the use of a special machine. This machine cuts a vertical slot in the soil to be filled up with reinforced concrete. Until the spouting of the reinforced concrete the cut is supported by Bentonite slurry. When the wall is completed, the internal structure of stations is prepared. Having completed the top slab structure the works advance under the surface. The following stages of work such as soil excavation and finally the interior decoration/construction of the stations take place at a minimum level of traffic detours on the surface, thus the noise concomitant with the construction works may also be minimized.