基于SBAS-InSAR和光学遥感影像的大型倾倒变形体变形演化

Deformation and evolution of large dumping bodies based on SBAS-InSAR and optical remote sensing images

岷江流域深层不稳定斜坡发育,揭示它们的变形演化特征对于稳定性评价和灾害防治有重要意义。以茂县梯子槽大型倾倒变形体为例,采用SBAS-InSAR监测和光学遥感解译结合的方法,获得变形体地表历史时序形变场。研究表明,梯子槽倾倒变形体前缘表现为垮塌破坏和鼓胀裂解复合破坏模式,垮塌区经历了形变由递增到减弱的破坏过程;在递增阶段倾倒变形体北侧形变量远大于南侧,而形变减弱后在南侧后缘形成了拉应力沉降区(-70.17 mm/a)、前缘因挤压应力集中而鼓胀裂解(-45.94 mm/a);形变减弱后变形体处于蠕变状态(年最大沉降量小于80 mm),但南侧后缘拉陷区与北侧前缘垮塌区形变对降雨和地震响应明显,表现为5~15 mm形变突增和回弹现象。本研究地表位移监测方法可以为形变量级跨度较大的不稳定斜坡演化分析提供参考。

Deep unstable slopes develop in the Minjiang River Basin,and revealing their deformation evolution characteristics is of great significance for stability evaluation and disaster prevention.In this study,taking the large-scale dumping deformation body of the ladder slot in Maoxian as an example,and the method of combining SBAS-InSAR monitoring and optical remote sensing interpretation was used to obtain the historical time series deformation field of the deformable body surface.The research shows that the leading edge of the collapsed deformed body of the ladder trough exhibits a composite failure mode of collapse failure and bulging cracking,and the collapse area has experienced a failure process from increasing deformation to weakening;in the increasing stage,the deformation amount on the north side of the dump deformer is much larger than that on the south side.After the deformation weakened,a tensile stress settlement zone(-70.17 mm/a)formed on the trailing edge of the south side,and the leading edge bulged and cracked(-45.94 mm/a)due to the concentration of compressive stress.After the deformation weakened,the deformed body was in a creep state(the maximum annual settlement was less than 80 mm),but the deformation of the south trailing edge collapse area and the north leading edge collapse area responded obviously to rainfall and earthquakes,showing a sudden increase of 5-15 mm deformation and a rebound phenomenon.The surface displacement monitoring method in this paper can provide a reference for the evolution analysis of unstable slopes with large deformation level spans.