基于时序InSAR的北京地区地面沉降对地下水开采的响应机理研究

Using InSAR and hydrogeologic time-series from 1991 to 2010, we characterize the hydraulic properties and the mechanism which land subsidence response to overdraft in Beijing area. The region is a unconsolidated, heterogeneous aquifer systems that supplies groundwater to Beijing. Current application of satellite interferometry to estimate aquifer hydraulic properties over large area is limited by the orbital error. It can propagate to the deformation data analysis and may even entirely obscure the interpretation. In this project, we present a new method that combines wavelet multiresolution analysis and least square to distinguish between the orbital errors and other components (e.g., atmospheric signal). Base on the 5 extensometer data, we analysis the stress-strain of aquifer system. This study aims to formalize the integration of InSAR results, storage, time, idual compaction and groundwater level time-series. Then we try to estimates the hydraulic properties (compressibility nd storage) in multi-aquifer system. All these results can help us reveal the spatial pattern and the mechanism of aquifer system. The study results can quantity be used to migrate the land subsidence in Beijing. And the results can be used to manage the regional groundwater to assure aquifer sustainability especially when the water of South-North Water Transfer arrive at Beijing.

以北京平原区为研究区，在现有常规监测网的基础上，开展遥感与水文地质、土力学交叉研究，揭示抽水作用下的地面沉降响应机理。针对大区域、缓慢地表形变干涉测量中轨道误差难以分离这一技术问题，提出采用小波多分辨率分解技术与加权最小二乘法结合，抑制其它误差组分影响，分解、评估轨道误差。在此基础上，分析沉降空间上的演化规律。结合分层观测数据深入分析含水层系统分层介质应力应变关系，建立监测形变与含水层系统水力参数、响应过程的关系模型。评估区域含水层系统水力参数，解决地下水资源评估计算、地面沉降预测中参数不确定性问题。从地下水可更新能力、地层岩性差异、含水层系统介质释水形变特性角度出发，研究残余形变空间分布模式，揭示抽水作用下含水层系统响应的空间各向异性机理。为北京地区地面沉降调控、南水北调客水进京后地下水资源调蓄提供科学数据和理论依据。

地面沉降是世界范围内突出的地质灾害问题，是受多种复杂因素驱动和影响的地质灾害。既涉及深部构造，又涉及中深层人类活动影响，同时叠加浅层地表系统互溃响应，由于对其机理认识薄弱，导致一些城市建设和重大工程受到破坏和威胁。如果得不到科学防治和有效缓解，将会严重影响高铁等重大工程运营安全和使用寿命，威胁地下水水质安全。项目开展遥感与水文地质、土力学交叉研究，揭示抽水作用下的地面沉降响应机理。研究发现多尺度分解和最小二乘法结合可以较好缓解干涉测量中长波长误差；不同深度地层形变有着不同的驱动机理，目前该区域地面沉降主要驱动力为抽水作用；断层带水力特性严重影响着抽水诱发应力分布及灾变模式；研究区差异沉降及地裂缝系活动构造-抽水共同影响的复合成因，灾害防治工程应采取提高断层带附近介质强度特性、非饱和带防侵蚀处理和地表水利设施改建综合措施。为区域地面沉降调控、南水北调客水进京后地下水资源调蓄提供科学数据和理论依据。