隧道净空 meaning in English

clearance of tunnel
tunnel clearance

This paper utilized the deformation characteristics of rock and expatiates on the strain test method of surrounding rock by which to judge the surrounding rock ' s stability , and to choose the suitable opportunity and style of the secondary lining
摘要利用岩体的变形特性，通过测试隧道围岩应变出隧道净空实际收敛量，从而判定施工过程中隧道围岩的稳定性，为选取合适的支护时机和方式提供依据。