InSAR Joint Modeling and Deformation Estimation for Highway Network in Soft Soil Areas

Objectives: Long-term deformation monitoring for highway network constructed in soft soil areas is essential. The plastic creep characteristic plays an important role in soft soil deformation. However, it has been neglected in most traditional InSAR time-series deformation models. To address this limitation, a joint modeling and deformation estimation method is proposed for highway networks in soft soil areas. Technology or Method: The processing of deformation modeling and parameter estimation are performed separately for subgrades and bridges. For the roadbed objects constructed in soft soil areas, a nonlinear visco-plastic body periodical precipitation (NVPBPP) model, which combines the Nonlinear Visco-plastic Body model with periodical and precipitation models to consider the plastic creep effects on temporal deformation for soft soil clay areas; for the bridge region, a thermal expansion linear (TEL) model and the traditional linear velocity model are incorporated, which characterizes the thermal expansion properties for bridge material. Results: The experiment is conducted on a highway network including roads and three bridges in a soft soil area in Beijing. The time series settlement from 22 January 2012 to 6 February 2015 is generated, with the maximum cumulative settlement estimated as 135 mm. The modeling accuracy of the NVPBPP model is estimated as ±6.5 mm, with 61.3% improvement compared to the traditional InSAR linear rate model; The external deformation cross-validation shows that our work has a high correlation coefficient of 0.97 with existed published results. Clinical or Biological Impact: Our method can provide data support and a reference for monitoring long-term health and ensuring transportation safety especially in poor soil regions.