自电位层析成像的理论与实验研究

为研究自电位异常场的物理机制，本文根据Patella半无限空间自电位层析成像的理论方法，对有限边界条件下的图像重建进行了研究，根据四边形界面处自电位的测量数据，重建出异常电荷的二维概率分布.文中对图像重建进行了数值模拟，分析了改进成像精度的措施，并对受压岩石的破裂过程开展了实验模拟研究，成像结果表明，实验中发现的岩石破裂的裂隙同正电荷出现的最大概率区域的位置基本一致，反映了裂隙尖端处正负电荷分离的微观过程.

Theoretical and experimental research on self-potential tomography

In order to reveal the physical mechanism of self-potential anomaly,this paper extends the theoretical method on SP tomography under the condition of half-infinite space proposed by Patella(1997),and gains the forward result under the finite boundary condition.With the observational data in the quadrangle space,the 2-D probability tomography of abnormal charges is reconstructed.A cuboid sample with a square section has been studied through several numerical modeling and experimental investigations,and the variation of abnormal charge with crack extension is revealed.It is found that the position of positive charges with a high probability coincides with the places of fractures in the rock sample.It reflects a microscopic process of separation of positive and negative charges at the fracture ends.This SP tomography is helpful to deeply understand the physical mechanism of electric field changes during the fracture of rock.