Monitoring method and monitoring element for vault crown settlement in subsurface tunnel

The invention provides a monitoring method and a monitoring element for vault crown settlement in a subsurface tunnel. The monitoring method is obtained on the basis of trigonometric leveling in a research and development manner, instrumental height and prism height do not need to be tested, errors can be greatly reduced, and the practicability is improved. A detection element consists of an observation plate (1), a screw nut (2) and a connecting rod (3). The monitoring method and the monitoring element have the advantages of simplicity in structure, reasonability in design, convenience in use and the like. 本发明提供了种暗挖隧道中拱顶沉降的监测方法及其监测元件，其中监测方法是基于三角高程测量而研发获得的，无需测量仪器高和棱镜高，可大大减少误差，提高实用性；所述检测元件由观测板(1)、螺母(2)以及连杆(3)构成，具有结构简单，设计合理，使用方便等优点。