Research And Application Of GBSAR High Slope Deformation Monitoring Under Complex Conditions

The excavation of the underground chamber may cause geological disasters such as subsidence and sliding to the surrounding environment,especially the stability of the nearby high slope is seriously threatened.Realize long-term,high-precision,real-time and continuous deformation monitoring of high slopes next to underground diverticulum,provide accurate monitoring data and early warning information before disasters occur,and formulate countermeasures to effectively avoid casualties and property losses.Ground-based synthetic aperture radar is a new type of deformation monitoring technology.Its frequency modulation continuous wave and synthetic aperture radar interferometry technology can realize non-contact regional large-area deformation monitoring.It has all-day,all-weather,continuous monitoring and short repetition period.And so on,the monitoring accuracy can reach the order of mm or even sub-mm.In this paper,the ground-based synthetic aperture radar Fast GBSAR system is used as an experimental platform to conduct experimental research on the ground-based radar system in the high-slope monitoring data processing method and high-slope stability analysis under the threat of underground dike excavation.main tasks as follows:1.Test the measurement accuracy of the Fast GBSAR system.The ground-based SAR system and the measuring robot are used to perform deformation monitoring on the Yuehu Bridge.During the inspection,five fixed-angle reflectors and one adjustable corner reflector are arranged on the bridge column.Comparing the adjustable angular reflector shape variable monitored by ground-based SAR with the micrometer adjustment,the results show that the ground-based SAR system can achieve a monitoring accuracy of 0.1 mm.Compared with the fixed-angle reflector deformation curve monitored by the ground-based SAR system and the measuring robot,The results are basically the same.2.Using the Fast GBSAR system to continuously monitor the high slope before the excavation of the chamber.During the monitoring period,the construction site is in normal construction state and the working conditions are complex.In order to reduce the impact of the construction environment,the natural environment and the instrument and human factors on the monitoring results,nine corner reflectors are welded on the surface of the high slope according to the principle of permanent scatterers.The data is processed to obtain a permanent scatterer deformation curve,and the instability of the observation platform,the interference of the external environment and the interference phase error are analyzed.3.Comparison of gross error detection methods for SAR data of high slope of diverticulum.The interference caused by the construction of ground-based SAR monitoring causes the monitoring results to be abnormally jumped.In order to remove these abnormal jump values,the least squares is introduced,and the absolute and minimum methods and the Tukey dual-weight method are used respectively.SAR measurement data is used for gross error detection.The comparative analysis of the high slope deformation monitoring data after the gross error removal shows that the Tukey dual weight method is more suitable for the ground-based SAR data gross error detection,which has the advantage of making effective use of the observation information and achieving the full use of the observation information.A balance between resistance and efficiency.4.Ground noise removal based on semi-parametric splines is proposed.The appropriate spline parameters are selected for the PS point to obtain an optimal estimate of the deformation information.The results show that the ground SAR data can be denoised by this method,and the correct separation between the two can be achieved when the noise and signal magnitude are different.5.Stability Evaluation and Suggestion of High Slope of Drainage Excavation Based on Ground-Based SAR.The ground SAR is used to monitor the high slope of the slope at the foot of the slope.The data is adjusted and the overall deformation of the high slope is in the range of-3mm ~ 1mm.Combined with total station,level and crack data,the deformation analysis of high slope is carried out.The deformation trend of each data is consistent and less than ± 3 mm/d defined by the construction design.Compared with the number of monitoring times of traditional instruments twice a day,the sampling frequency of ground-based SAR is higher,which can better invert the actual deformation of high slope and provide reasonable basis and protection for high slope stability and diverticulum excavation.Suggest.