The Necessity and Feasibility of the Establishment of the Unprotected Area in the Air-raid Project

The unprotective area is suitable for five-degree or six-degree air-raid projects for peacetime and warfare. Whether to set up the unprotective area is determined by the usual economic, social and environmental benefits. Meanwhile,the unprotective area and its proportion are also determined by the need and benefit for warfare and also by the need for fire-protection. The essay is, on the basis of the program design, construction and operation of Zhengzhou railway station square's underground project, to prove the necessity and feasibility of the unprojective area.