纵轴线 meaning in Chinese

longitudinal center line

Optimized design on the direction of longitudinal axle of underground plant
关于地下厂房纵轴线方位的优化设计
It was shown that the maximum displacement occurred on the tunnel axis when one tunnel was excavated , while the maximum value happened near the shallow tunnel and between the area of two tunnels when two adjacent tunnels were excavated at the same time
分析结果表明：单条隧道开挖引起的地表最大沉降值出现在隧道轴线的正上方，而两左右或上下相邻隧道开挖的地表及土层内部的最大沉降值则出现在两隧道的纵轴线之间，且偏向上方埋深较浅的隧道。