In Shanghai, China, a huge hole formed in the asphalt, ending up swallowing a large stretch of roadway near a construction site for the new Jiamin subway line. As can be seen in the video above, taken by surveillance cameras, the road surface suddenly gave way causing a hole between 10 and 20 meters wide: the accident occurred in Qixin Road and Li’an Road, in the Minhang district.
Fortunately, passers-by and construction site workers managed to save themselves before the ground collapsed completely: the collapse caused no injuries or victims, but the authorities still closed the surrounding streets for safety reasons, launching investigations on nearby buildings.
But how could this happen? According to the first information released, the intersection – recently built – collapsed due to a water leak reported the day before at the construction site, which probably contributed to the weakening of the ground beneath the road, causing its sudden collapse a few hours later.
Several local newspapers, however, have underlined that episodes of this kind are not new for the city of Shanghai, given that the city has a problem of soil subsidence, a phenomenon that consists of slow process of soil subsidence caused by geological factors, but also aggravated by human action.
In fact, there are two main reasons behind the land subsidence of Shanghai, as reported in a study published in the journal Engineering Geology: hydraulic stress, with the massive extraction of some aquifers which reduced the water pressure, causing the adjacent clay layers to collapse, and load stress, due to the building load of large structures and skyscrapers.
