Jointly reconstructing ground motion and resistivity for ERT-based slope stability monitoring
Jointly reconstructing ground motion and resistivity for ERT-based slope stability monitoring
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DOI：
10.1093/gji/ggx453
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发表时间：
2018-02-01
影响因子：
2.8
通讯作者：
Adler, Andy
中科院分区：
文献类型：
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作者：
Boyle, Alistair;Wilkinson, Paul B.;Adler, Andy
电阻率层析成像(ERT)越来越多地被用于调查不稳定的斜坡和监测其内部的水文地质过程。但是，相对于假设的模型，电极的移动或电极的不正确放置可能会在重建中引入显著的电阻率伪影。在这项工作中，我们演示了一种迭代高斯-牛顿框架下的联合电阻率和电极运动重建算法。我们将其应用于英国一场活动缓慢移动的山体滑坡的ERT监测数据。结果表明，电阻率伪影较少，表明在一定条件下，电极运动和电阻率可以同时重建。提出了一种新的2.5维电极位置雅可比公式，与三维模型的伴随方法相比，该公式能给出精确的数值解。在大型有限元网格上，新方法的计算时间也被证明比三维伴随方法快一个数量级，并解决了二维摄动和伴随电极位置雅可比的建模误差。
Electrical resistivity tomography (ERT) is increasingly being used to investigate unstable slopes and monitor the hydrogeological processes within. But movement of electrodes or incorrect placement of electrodes with respect to an assumed model can introduce significant resistivity artefacts into the reconstruction. In this work, we demonstrate a joint resistivity and electrode movement reconstruction algorithm within an iterative Gauss-Newton framework. We apply this to ERT monitoring data from an active slow-moving landslide in the UK. Results show fewer resistivity artefacts and suggest that electrode movement and resistivity can be reconstructed at the same time under certain conditions. A new 2.5-D formulation for the electrode position Jacobian is developed and is shown to give accurate numerical solutions when compared to the adjoint method on 3-D models. On large finite element meshes, the calculation time of the newly developed approach was also proven to be orders of magnitude faster than the 3-D adjoint method and addressed modelling errors in the 2-D perturbation and adjoint electrode position Jacobian.