Is it qualified to pile more than 20 meters of stones?

Unqualified. According to "Technical Code for Safety of Masonry Engineering", it is suggested that steel members and plastic-steel sheds should be used for sand silo sheds, with a clear height of not less than 7.5 meters and not more than 20 meters. The storage yard must be hardened, firm, flat and tidy, and cleaned regularly to avoid secondary pollution. Stone refers to the rock used in architecture, sculpture and other materials or similar substances. Stone generally refers to all the stones that can be used as materials, such as granite, shale and slate. Rockfill, masonry and stone slag are also stones.