Experimental Research On Electrical Spectrum Lines Characteristic Of Rock Fissure

Rock fissure belongs to a lower tectonic level in the rock mass and controls the stability of the rock mass. Meanwhile, it is related to flow and transportation of underground fluid, storage of oil gas and so on. So, testing of fissure has a great significance.At present, main methods of testing rock fissure are ocular identification, geophysics method, structuring physical model, acoustic frequency spectrum detection, artificial intelligence technology and so on. But, it has a great difficulties to research the fissure because the complex cause of fissure, multifactor of controlling and influence, randomness of forming and growing, high non-homogeneous of distribution. So, existed research approach has its own defects and limitation, and there is no clear understanding of distribution law.Aqueous solution existed in the rock fissure, providing routeways to the directional flowage of electriferous ion. For the sake of information about the fissure structure by minuteness ion substance, we carry through the studies about electrical characteristic.On the basis of the studies and application about electrical characteristic from forefathers, in the interest of parameter about the rock fissure, this text researches the fissure by experimental study using electrical spectrum lines characteristic from electric conductivity of moisture rock.The measuring system with AC changeable frequency is set up, and the rock electric resistance on andesite, tuff, rhyolite, marble, schist, ashstone, and other 9 types of rock in the frequency range of 50Hz to 600kHz are performed without the induced polarization of rock. Finally, we get the test spectrum results of fissure resistance R arranged by AC frequency f. Each rock sample layouts a number of different directions measured lines and then draw all testing lines on a graph. In this way, a cluster of rock fissures resistance lines which called spectrum lines are formed.The article analyses spectral characteristic from three parts:typical spectrum line symbols, pertinence of each spectral curve and fissure's sensitivity to frequency. We get three conclusions. Rock fissure resistance has two cases along with the frequency increasing:First, rock resistance reduces with the frequency enlargement and then it increases; second, along with frequency enlargement, the rock resistance has reduced. According to the different speed and scope of the resistance, the article withdraws 12 kinds of typical electrical spectrum line symbols; One sample's electrical spectrum lines shape has nothing to do with the length and the orientation of the testing line, but each spectrum curve is anisotropy; Essential mineral is a laminated shape, and it assumes the directional arrangement in the rock. In this situation, each spectrum line also assumes the directional arrangement.This text establishes parallel connection circuit, and then convert impedance module into polynomial expressions using the series expansion and variable substitution. These expressions are related to the expressions from the experimental data fitting, showing that assembled circuit model can very express the frequency conversion properties of rock fissure resistance.Typical spectrum line symbols used to identify characteristics of different groups of rock fissures, providing test methods for detecting and contrasting the rock fissure. The study combines the electrical parameters with the parameters of fissure, laying a foundation to express geometrical parameters of rock fissure by using electrical parameters.