单轴压力下岩石磁化率的变化

THE VARIATION OF ROCK SUSCEPTIBILITY WITH UNIAXIAL PRESSURE

摘要:

利用感应法测定了北京、唐山地区五类强磁性火成岩在单轴压力下的压磁曲线。实验发现,曲线可划分为两个形态不同的阶段。在加压的初始阶段,压磁曲线表现为上升;尔后,几乎以不变的速率直线下降。曲线形态与岩样的种类、循环次数有一定的关系。压磁系数变化范围为-(0.9-3.0)×10^-4cm²kg。从加压开始到岩石破坏,磁化率一般下降20-30%。还发现,磁化率的变化与岩样的体膨胀关系不太明显。
运用铁磁学中的磁畴理论对上述压磁曲线作了初步的解释。

Abstract:

The piezomagnetic curve under uniaxial pressure has been measured by inducing method to the five kinds of strong magnetic pyrogenetic rocks in Beijing-Tangshan region. It has been found out in the test that the curve may be divided into two different morphological phases. The curve of piezomagnetism rises when the pressure is exerted on it in the iniatial stage, and then it falls straight at an invariant speed. There exists a certain relationship between the curve form, the kind of rock specimen and the number of circulation. The variation of piezomagnetic coefficient is-(0.9-3.0) ×10^-4cm²/kg. on an average magnetic susceptibility decreases 20-30 per cent from the beginning of pressurization to the rock destruction. It has been discovered as well that there does not exist a clear relationship between the variation of susceptibility and volume expansion of rock.
This paper gives a preliminary explanation to the piezomagnetic curve mentioned above with the theory of magnetic domain in ferromagnetism.