unlined tunnel meaning in English

无衬砌隧洞

The construction of the multiple - arch tunnel is deeply related to the form of center partition , the tunnel ' s section and excavation method etc . the change regularities of stress field caused by excavation are studied by 4 multiple - arch unlined tunnel model tests . the difference in lining for various multiple - arch sections is analyzed and the mechanics characteristics of center partition is discussed . then , a reasonable construction method for multiple - arch tunnel and a better section are put forward
通过4个连拱模型试验，研究了连拱毛洞开挖引起的应力场变化规律，对不同的连拱断面的衬砌受力差异进行了深入的分析，同时对中隔墙的受力特点也作了探讨，提出了合理的连拱隧道构筑方法及优化断面图。