中洞 meaning in English

middle hole(par 4)

Study of leigutaizhongdong at the longmen grottoes
龙门石窟擂鼓台中洞之研究
Technology of center drift method for subway station in beijing
北京地铁5号线磁器口车站中洞法施工技术
With the rapid development of the state highway construction , it becomes more and more important for the study of stability of peripheral surrounding rock and its forced condition of the structure during construction of railway or highway tunnels , especially of those long or extra - long tunnels
随着我国高速公路建设的高速发展，铁路、公路隧道，特别是长大和特长隧道施工过程中洞室周边围岩的稳定性与结构受力状态的研究日益显得重要。