Research on Deformation Law of Deep Foundation Pit of Station in Core Region of Saturated Soft Loess Based on Monitoring
Table 2
Main items of foundation pit monitoring.
Serial number
Monitoring items
Monitoring instrument
Measuring point layout
Measurement accuracy
Allowance
1
Surface settlement around the pit
Level
Arrange 2 rings along the circumference of the pit, the first ring is 2.0 m away from the periphery of the foundation pit, the second ring is 8 m away from the periphery of the first ring, and the distance between the measuring points of each ring is 10–20 m
1.0 mm
0.3%H or ≤30 mm, whichever is smaller
2
Horizontal displacement of diaphragm wall
Theodolite Total station
Layout along with the middle and outside corners of the periphery of the foundation pit, with a spacing of no more than 20 m, and no less than 3 underground continuous walls on each side
1.0 mm
0.2%H or ≤30 mm, whichever is smaller
3
Support axial force
Axial force gauge Strain gauge
The deformation of the diaphragm wall is set at the same monitoring section, and the vertical supports at the same section position are set at measuring points
0.15%F.s
0.8f
4
Groundwater level
Water-level pipe Water-level meter
The midpoint of the long and short sides of the foundation pit, and the distance between 20 and 50 m when the foundation pit is large, needs to be combined with the precipitation plan
