SBAS-InSAR Deformation Modeling And Estimation Of Highway Built On Soft Clay Subgrade Considering Rheological Parameters

The post-construction deformation is one of the most important reasons inducing the uneven settlement,cracking and collapse for those highways built on the soft clay area.The rheological properties of the soft clay seriously affect the normal operation and daily safety control of the highway.Therefore,long-term deformation monitoring of highway on soft clay subgrade during the post-construction period is of particular significance.Although the traditional time-series InSAR technology processes the ability to monitor the deformation of soft clay,most of the empirical mathematical deformation models used in InSAR cannot accurately describe the nonlinear temporal deformation evolution,which will seriously affect the accuracy of the final estimated deformation.Based on those deficiencies of the traditional models,combined with the theory of Rheology,our study aims at constructing a novel InSAR deformation model by introducing the rheological parameters into traditional deformation models.The main research work and achievements are summarized as follows:(1)The deformation of soft clay presents complex nonlinear characteristics with time.By analyzing the deformation mechanism of the soft soil,the novel InSAR deformation models considering rheological properties and environmental factors are constructed,including the time-series deformation model based on Maxwell model and Burgers model.(2)Genetic Algorithm combined with Simplex Method is used to obtain the unknown parameters of the novel models.Both simulated and real data experiments are carried out to verify the accuracy of the novel model and the reliability of the parameter estimation algorithm.The simulation results show that the parameter estimation results can maintain good stability even under high level noise.In the real experiment,Yanhu Avenue in Dongting Lake,Lungui Highway and G1508 Highway in Foshan City are selected as the test highways.The estimated model parameters and time series deformation results are acquired.(3)The influence of the estimated error for the model parameters(rheological parameters,subsidence velocity,and environmental factors)on the estimated deformation results is revealed.The correlation between the environmental factors and the time series deformation is analyzed,and the temporal-spatial deformation characteristics of the study area are interpreted in detail.(4)Accuracy validation of the estimated deformation based on the new models is carried out.Three indexes including residual phase,temporal coherence,and high-pass deformation component are used to verify the reliability of the estimated time series deformation.Besides,the experimental results of Lungui Highway are compared with the external leveling data.