A.D. Sashourin & A.A. Panzhin, EXPERIMENTAL RESEARCHES DYNAMICS OF DISPLACEMENTS IN FAULTS ZONES, Mining Institute of Urals Division RAS, Ekaterinburg, Russia, http://igd.uran.ru/geomech/articles/sad_001/index.htm

EXPERIMENTAL RESEARCHES DYNAMICS OF DISPLACEMENTS IN FAULTS ZONES

A.D. Sashourin & A.A. Panzhin

Mining Institute of Urals Division RAS, Ekaterinburg, Russia

N.K. Kostrukova & O.M. Kostrukov

Scientific-practical center "Geoecology", Surgut, Russia

Abstract: The paper includes results of experimental researches of dynamics displacements and deformations in zones of tectonics faults. The experiments were carried out on three faults zones located in Western Siberia in area of Surgut city. The displacements of a surface measured with applying systems of a satellite geodesy GPS. The measurements were executed in a mode of continuum monitoring with code-reading of results in 5 seconds, 10, 15 and 30 minutes. The experiments have revealed presence short-period of surface oscillatings in faults zones and on bordering territories. The discovery of dynamics displacements and deformations cardinally changes conception about parameters and laws of forming of the stress-deformed state of a rock mass in a natural conditions. The magnitudes of displacements and deformations are capable to arouse breaking downs in objects getting in a zone of their influencing. The researches are executed at financial support of the Russian Foundation for Basic Research (RFBR).

1. INTRODUCTION

The humanity in the own daily activity has got used to be guided by submissions about the Earth as "unrequited earth stronghold". Today all know about movements of lithospheric plates, about movements on such active faults as San-Andreas in California, North-Anatolisky in Turkey etc. In other parts the Earth - as environment of mining, underground structures, the basis for all kinds of building etc. - is represented as something static, stable.

In reality it is far from being so. The tectonics faults even of a low rank in general hierarchy of a block structure of a rock mass have the some mobility. She not always carries directional trend pattern, but can be introduced also dynamics oscillatings, aroused while by unknown endogenics processes. The look-alike contradictions of existing submissions are conjugate to real processes in an earth-crust with severe hazard to the objects, which have appeared in affected area of movable tectonics patterns. Most contrast this contradiction was reveal on extended objects, such as main oil pipelines and gas lines, underground manifolds etc. But specially it is important for ecologically dangerous objects, the emergencies on which one can become the cause of ecological disasters. To them it is possible to relate nuclear power stations, underground and ground-level storage of nuclear wastes.

In the paper the results of researches dynamics of faults zones, introducing interest in fundamental and problem fields of knowledge are given.

2. ORGANIZATION OF EXPERIMENT

From the end of the nineteenth century and until recently the stress-deformed state of a rock mass in geomechanics, geodynamics and other sciences about the Earth was represented as something static. The representation about its parameters, about parents their reasons, about dependences between values of stresses both deformations and bases of their measurements varied. But same remained invariable - static state of parameters of stresses and deformations in historical intervals of time. The dynamic or slow variations on the established concepts occur or for durable geological periods, or on a sites of progressing and display of geodynamic processes on short interims.

At 70-80 years of past century in scientific researches even more often meet of papers on researches dynamics of parameters of the stress-deformed state in interrelated the tidal phenomens from influencing the Moon and Sun. Today in many papers the question about fluctuations of parameters of the stress-deformed state is bring up, and anybody from geomechanicist will not become to deny dynamics of the stress-deformed state. But in practical sphere dynamics of stresses and deformations does not find the reflex. It takes place for the simple reason - nobody knows parameters of dynamic processes: amplitudes and frequencies of occurring variations.

At the same time, by practice exploitation of main oil and gaseous pipe lines and other extended objects is established, that the emergency breakings on them are clustered, more often, in zones of tectonics patterns. The mechanism of their breaking down in these zones allows suspect about presence of dynamics variations in the stress-deformed state of a rock mass and pipe line, laid on him. These conditions have induced to carry out experimental researches of dynamics of the stress-deformed state of faults zones.

4. TECHNIQUE OF EXPERIMENT

Dynamics of displacements in faults zones was researched with applying of technique of satellite geodesy. Is immediate were measured mutual vertical and horizontal displacements of two marks of special observant stations equipped on investigated areas. For these purposes the kit of instruments of firm Trimble (USA) series 4600LS, including four GPS receivers was used.

The observant stations represented system of marks locked on ground surface with the use of pilling metallical datum marks. The applying of datum marks provides an opportunity of review of experiments. On the first object in area of an oil pipeline 15 marks of observations, and on second 13 were equipped.

The measurements were executed on technique of differential GPS in a uninterrupted mode with periodicity of code-reading 5 seconds, 10, 15 and 30 minutes. Simultaneously in operation there were 4 receivers located on 4 datum marks. It provided monitoring behind variations of lengths and leveling at 6 vectors. In total was executed of measurements on 29 vectors on the first object and 35 vectors on second. The endurance of continuous observations on each vector was various and amount from 1.5 hours till 30 hours.

The implementation of all requirements make to planning and execution of measurements, and also to post-processing of experimental data, provides accuracy of definition of a mutual position of two receivers within the limits of 1-3 mm. During executing of measurements the special check confirming the specified accuracy was carried out.

5. RESULTS OF MEASUREMENTS

The deformations of vectors observant stations in the tables are given in absolute and relative values. For horizontal deformations this variation of vector length (millimeters) and relative elongation. For vertical deformations this variation of elevations confining datum marks (millimeters) and variation of inclination.

As whole is not revealed yet existence of the determined intercouplings of deformations with a direction of vectors concerning tectonic disturbances. Probably they will exhibit themselves at the subsequent researches and accumulation of the experimental information.

6. DISCUSSION OF RESULTS

The obtained experimental data about presence dynamic forms of movements in zones of tectonic disturbances and aroused by them alternating deformations and movements entails severe fundamental and problem consequences. In fundamental area they, first of all, are connected to aggravation of submissions about the natural stress-deformed state of a rock mass.

Presence dynamic forces in zones of tectonics faults, which one, apparently, have an endogenic genesis, causes many features in progressing and existence of the stress-deformed state not only faults zones, but also in the whole rock mass. But it leaves for frameworks of the given report and, is interquartile, will serve as a theme of other researches.

It is difficult to overestimate a role of dynamic deformations and in problem sphere. All artificial objects which have got on tectonics faults with dynamic deformations, is undoubtedly will appear under their affecting, testing influencing fatigue effects from cyclic loading. According to the obtained frequencies, the construction will be subjected not less than 500000 cycles loading per one year. First of all extended underground objects, such as gas mains and oil pipelines, water lines, heating mains, sewage headers, undergrounds etc. are exposed to affecting of dynamic deformations.