Fig 1.
FFBPNN structure.
Fig 2.
Flow chart of FFBPNN.
Fig 3.
Prediction flow chart of GM-FFBPNN model.
Fig 4.
Study area: (A) The map of China; (B) The map of Beijing; (C) Site topography and geomorphology; (D) Ground fissures.
Fig 5.
Drilling test: (A) Car drilling rig; (B) Rock sample.
Fig 6.
Geophysical exploration test: (A) Diagram of instrument; (B) Results of geophysical exploration.
Fig 7.
The observation curve of monitoring points.
Table 1.
The measured data of N22 monitoring points.
Fig 8.
Cumulative settlement and settlement velocity curve of N22 monitoring points.
Table 2.
Model building results.
Fig 9.
FFBPNN structure diagram.
Fig 10.
Fitting regression diagram of subsidence prediction model.
Table 3.
Comparison between original and predicted values of the two models.
Table 4.
Prediction accuracy test table.
Fig 11.
Comparison of predicted value and original value curve.
Fig 12.
Comparison of four threshold denoising effect curves.
Table 5.
Denoising quality evaluation table of different threshold methods.
Fig 13.
Approximate signal and detailed signal diagram after decomposition.
Table 6.
Cumulative settlement and predicted value of N22 monitoring points after denoising.
Fig 14.
Comparison of residual value before and after denoising.