Design and Application of Risk Early Warning System for Subway Station Construction Based on Building Information Modeling Real-Time Model

Table 2

Layout of surveying points for monitoring project.

Items	Monitoring range	Layout and spacing of surveying points	Accuracy
Subsidence	1–3 times of the ground around the foundation pit and soil in the depth of the foundation pit	1 every 15–20 m along the longitudinal direction of the station	0.3 mm
Horizontal displacement and settlement of wall top	Upper of continuous wall	1 every 15–20 m along the longitudinal direction of the station	1.5 mm
Wall deformation	Within the enclosure	20 m spacing and 0.5 m spacing in the same hole in the vertical direction	1.0 mm
Axial force for support	1/3 of the steel support between two points at the end	Set for each layer at 30% of support, at least 3	≤0.5% (F.S)
Groundwater level	Surrounding of the foundation pit and objects to be protected	Layout in 20–50 m spacing to monitor the section	10 mm
Settlement and horizontal displacement of surrounding buildings	Buildings (structures) to be protected	Four corners of a building, every 10–15 m along the outer wall	1.0 mm
Settlement and displacement of underground pipeline	Important municipal pipelines around the foundation pit, such as power tunnel, gas pipe, and water supply pipe	5–10 m spacing	0.5 mm
Soil pressure	Within the enclosure	20 m spacing	≤0.5% (F.S)
Observation of building cracks	Related building (structures)	It depends	0.1 mm