1)apsidal motion,拱线运动2)apse line,line of apsides,拱线3)circular apse line,圆拱线4)apsidal rotation,拱线转动5)springing line,起拱线6)spring,line,起碹(拱)线
用法例句
The author searches the new method of construction survey for tunnel circular apse line,which measuring point displacement method in the tunneling construction practice.