The electric potential changes under uniaxial loading in some minerals and
rocks have long been recognized. To daylight the electrical response of
some minerals and rocks against applied stress, both theoretical studies
and laboratory experiments are conducted. Some theories are also
proposed by different researchers, in order to explain the electric potential
variations. However, the mechanisms leading to electrical potential
generation have not been fully explained yet.
In the explanation of electric potential changes observed in rocks, type of
the observed rock and the rock forming minerals in the rock fabric play an
important role. One theory is based on the fundamentals of piezoelectricity
only. However the relation between the stress state and the electric
generation is not fully understood. This thesis aims to make a further
contribution to the studies on understanding the electric potential change in
rocks, containing quartz, which is a common piezoelectric mineral, under
uniaxial loading conditions.
Three types of rocks, namely quartz-sandstone, granite and granodiorite,
are tested, and the stress and electric potential (EP) variations are recorded
during the uniaxial loading experiments in a continuous manner. The
experiments are conducted at three different loading rates, in order to
investigate the effect of loading rate on the electrification mechanism. Also
step loading experiments are conducted.
Results indicated that, application of uniaxial stress creates a clear change
in the EP responses of three quartz bearing rock types. The possible
relationships between the EP generation and the level of applied stress are
investigated based on the initial and final potential values (EPinitial, EPfinal),
the potential just before the time of failure (EPUCS), the spike-like potential
jump at the time of failure (& / #8710 / V), which are derived from the recorded data of
the experiments.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12605480/index.pdf |
| Date | 01 October 2004 |
| Creators | Inal, Sinan Hikmet |
| Contributors | Bilgin, Aydin Hasan |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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