One way to solve it is that you can use a sniper rifle to destroy the sinkhole.But remember not to destroy it while the big worm is outside,or you will get a very,very,very big trouble.(If the sinkhole is broken and the worm hasn't been back, it will never disappear without being killed.)
(By the way, I'm a Chinese player and this is my first time to offer information to foreigner on steam……If I make mistakes in grammar,please forgive me,thanks.)