APPLICATION OF ELECTRIC EXPLORATION AND ATMOGEOCHEMICAL TECHNOLOGIES IN SEISMIC MICROZONING OF A TUNNEL JUNCTION THROUGH THE MARKOTKH RIDGE
Authors:   Southern Federal Institute, FOMENKO Nikolay , BOROVIK Natalia ,   Wellard, Western Australia, GAPONOV Dmitriy ,   Open Joint-Stock Company "Geostroy-F, FOMENKO Ludmila ,   Don State Technical University
Published: February 2021

Aim. Investigation of the electrical exploration effectiveness and atmogeochemical technologies for detecting discontinuous and folded tectonic disturbances during seismic microzoning of the tunnel crossing over the "Markotkhsky ridge" Task. Study of the tectonic disturbance degree and flooding of the flysch strata using spatial electrical filtration, electropotential tomographic sensing, and atmogeochemical measurements along the tunnel route using data from route surveys and drilling at the tunnel design site. Research methods. 1) Field electrical survey measurements of spatial electrical filtration and electropotential tomographic sensing and with installations of multidirectional electric field excitation for" highlighting " target objects. 2) Using a multi-variant system for presenting field data in the form of tomograms and in the form of electro-profiling and sounding to identify destructive zones related to tectonically disturbed rocks and flood zones. Research results. The analysis of domestic and foreign publications on the use of electrical exploration methods in seismic microdistricting of design, construction and operation of critical facilities is performed. On the example of a tunnel crossing over the Markotkhski ridge: 1) geological, geo-ecological, and seismological characteristics of the area of engineering and geophysical research are considered; 2) the field studies of spatial technologies electric filtrazione, electropotentials tomographic probing and atmogeochemical of observations are produced; 3) the heterogeneity of fliteway thickness laterally and quasioperational this thickness on the electrical properties at depth is shown; 4) as a result poperechnogo analysis curves electropotentials tomographic probing, as well as charts of the spatial electric filtrational and atmogeochemical measurements of an tectonically disturbed and watery areas are identified; 5) the degree of differentiation of the flysch thickness by the values of the specific electrical resistance was estimated using a pseudo-section constructed in the Res2Dinv program. Conclusions. The technologies of electropotential tomographic sounding and spatial electric filtration are unique in terms of mobility and simplicity of field measurements, subsequent geological and geophysical interpretation of anomalous values of the electric field based on its redistribution in tectonically and technogenically disturbed geological structures. The result is the identification of places of development of tectonic discontinuities and watered zones, information about which makes it possible to predict, along with the seismicity of the rock mass inside the tunnel, possible places of potential collapse and flooding during the design, construction and subsequent operation of tunnel crossings. A significant achievement of the experiments can be attributed to the identification of the possibility of electroprobing the flysch strata with steeply-and obliquely-lying layers by dipole electric exploration installations. The proof is that the growth of the right branches of the probing curves does not exceed 45°. Consequently, the steeply-and obliquely-lying flysch strata can be considered heterogeneous laterally and quasihomogeneous in depth in terms of electrical properties.