The 4 subsidences happened along the construction site of Dongguan - Huizhou intercity rail during March 6 to March 11. The biggest one which happened near Changping Avenue, created a big hole of 50 square meters.
300 people were evacuated after the first accident, no casualty is reported.
Preliminary research shows that the main reason for the accidents is that the load bearing rocks above the rail tunnel lost its stability due to pipe leak around them.
At present, the operation has come to full stop and will not restart until safety is secured.