What is ditch sealing and wall sealing?

Blocking ditches and walls are blocking and defending means in military defense and border control.

The blockade ditch is a deep and wide ditch, which is used for the defense of military sites, cities or borders. It can prevent the enemy from attacking or crossing the border, increase the difficulty of the enemy's attack, and bury explosives or traps for ambush. The blockade wall is a high wall or barrier built at the border or conflict area to restrict the flow of people and materials. It is usually made of concrete, steel bars and other materials, and its height can reach several meters or even more than ten meters. The main purpose of blocking the wall is to prevent illegal border crossing, control border immigration or prevent enemy invasion.