Nonmagical walls of solid stone springs into existence centre on you going in 4 direction, North, East, South, West up to 30 feet in each direction. The walls are 3 inches thick and 8 feet high. 

If the wall cuts through a creature's space when it appears, the creature is pushed to one side of the wall (your choice). 

The wall is an object made of stone that can be damaged and thus breached. Each wall has technically 3 panels each 10 feet long and each panel has AC 15 and 15 hit points. Reducing a panel to 0 hit points destroys a 10 foot area of wall.

If you maintain your concentration on this spell for its whole duration, the wall becomes permanent and can't be dispelled. Otherwise, the wall disappears when the spell ends.