Standing pile is a kind of dance, which can be seen in the Shasha Ballroom in Chengdu. When dancing, both sides stand still, just like piling on the ground. Some people call it standing pile.
The ballroom is a commercial entertainment place. From Sai Jinhua to Fengxian Xiao by Han Ying: At that time, even in Shanghai, a city famous for its foreign markets, no ballroom was open for business.