The worst unexpected happened in São Paulo Metro Line 6 construction. The shaft which was opened for metro construction on Marginal Tiete side has caused subsidence of ground. It emptied the ground under the Marginal Tiete expressway next to it. Subsidence caused the collapse of the much of the 4 lane expressway.

Thanks to god there are no human life casualties.

But what caused this failure? Several different probable causes are claimed by different authorities reported in Brazilian press. In essence, authorities step on each other. São Paulo governor João Doria claimed that constructors hit a sewage collector. But governors claim rejected by André De Angelo Brazil country director of Acciona in the very same press conference.

In the news written Acciona's shares in Madrid dropped a little bit. Acciona had been awarded the 2.59 Billion US dollar contract to build 15 kilometer long São Paulo Metro Line 6.

You can see in the news video how it is slowly eating up the ground under the expressway to the outer walls of the tunnel shaft. Then you see all ground and water disappear in the shaft. I think it flooded the tunnel construction. It will cost too much to undo all this. Very sad.

In the press conference performed at the construction site, governor João Doria brings up the theory that constructor machinery hit the sewage collector as the cause of whole mess. He praises Acciona as a world leader in tunnel construction. But André De Angelo, the country manager of Acciona in Brazil is very clear rejects that the accident has not been caused by their tunneling machinery hitting the sewage collector. He says everything was mapped and he is very clear that such a clash did not happen contrary of what the governor says. You can hear that from about minute 5:05.