LAST HUNDRED METERS OF THE SECTION UNDER THE DANUBE WILL BE HARDER THAN THE PREVIOUS PART

As closing to the Pest side the south TBM of metro 4 has got into a fault zone and it has to work now in clay with a consistency different than that of the previous part, and the TBM has to be adjusted to the new condition. At the construction of the Buda side after leaving Szent Gellért Square there was a short section under the Danube with similar consistency clay, and the TBM was able to proceed with works following a cleaning. Likely from tomorrow experts under caisson pressure will clear the cutting shield that withdraws to approximately half meter, now they are being prepared.
Until last Friday the south TBM covered approximately 190 meters of the 300 m stretch under the Danube, then approaching to the Fővám Square station it got into a fault zone, where the different structure clay material likely stuck into the TBM’s cutting shield. In the environment of fault zones the soil conditions are always vary from the average. Situations similar to the one now can occur anytime during a metro construction, the experts are prepared for these; moreover the tunnel building machine of metro 4 is one of the most state-of-the-art methodology options used on the World now, which allows the experts to continuously adjust the machine to the extremely diverse soil conditions under Budapest.

It will happen now also. After cleaning the TBM so adjusted according to the special soil conditions will proceed with a special diluting agent being injected. The south TBM set off on its way under the Danube on 18th May, and as it was communicated earlier by DBR Metro Project Directorate, it will likely be working across this section for 4 to 6 weeks in total. If they succeed to fully survey the section in front of the TBM within a couple of days and to clean the cutting shield from the material stuck to it, the machine will get to the Pest side in time as planned and its north pair can set off on its way under the river bed also.

Budapest, 9th June 2009

DBR Metro Project Directorate