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Characterization of the Excavation Damage Zone (EDZ) in different geotechnical conditions
Staš, Lubomír ; Waclawik, Petr ; Souček, Kamil ; Vavro, Martin ; Zajícová, Vendula
In order to realize a comparative study of the Excavation Damage Zone (EDZ), two lithological and geotechnical different localities were selected. The first locality is located in the metamorphic rocks of the Rožná Mine. The second locality is located in the volcanic-sedimentary series of the Experimental gallery Josef. In order to evaluate the range of the EDZ, a combination of geotechnical and laboratory methods was used at the mentioned localities. The geotechnical method included the qualitative evaluation of the rock mass using the RQD index on the borehole core. The RQD index and failures of borehole walls were also determined based on OBI and ABI methods. In the laboratories, the pore space was characterized using X-ray computer micro-tomography (X-ray) and high-pressure porosimetry (MIP). The research report summarizes the results of these methods.
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Determination of rock mass failure using acoustic and optical television - volcanic rocks, Experimental gallery Josef
Staš, Lubomír ; Waclawik, Petr ; Souček, Kamil ; Vavro, Martin ; Kubina, Lukáš ; Rutar, Tomáš
In order to evaluate the geological structures on the boreholes walls, using optical and acoustic logging methods (OBI and ABI) the boreholes were logged at the Experimental gallery Josef. Optical and acoustic recording was performed in the down borehole (JT1) using an optical (OPTV - Optical TeleViewer) and acoustic (HiRAT - High Resolution Acoustic Televiewer) televisions. Due to the inclination of the horizontal borehole (JTGeo01) -10°, oriented records by both methods (OBI and ABI) were made too. The measured oriented records by OBI and ABI methods were processed and evaluated in WellCAD software for logging data processing. Based on the evaluated structural data, a structural cross-section was constructed, which was the background material for correlation with geophysical data.
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Geotechnical evaluation of exploration borehole No. JTGeo01, Experimental gallery Josef
Staš, Lubomír ; Waclawik, Petr ; Souček, Kamil ; Vavro, Martin
In order to carry out the third cycle application of geotechnical methods, the experimental gallery Josef was selected. Due to the conditions and the existing infrastructure, the roadway No. SCHZ-JP9 was selected. Mentioned roadway is situated in a volcanic-sedimentary series formed by tuffite rocks, which will enable mutual comparison of the rock mass failure formed by different types of rocks at individual selected localities. For the purposes of the application of geotechnical methods, the exploratory core borehole No. JTGeo01 with a diameter of 76 mm was drilled. The presented research report summarizes the geotechnical evaluation of the rock mass on the basis evaluation the mentioned borehole.
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Determination of rock mass failure using acoustic and optical television - metamorphic rocks, Rožná Mine
Staš, Lubomír ; Waclawik, Petr ; Souček, Kamil ; Vavro, Martin ; Kukutsch, Radovan ; Rutar, Tomáš ; Nohejl, Zdeněk
In order to evaluate the geological structures on the core boreholes walls, using optical and acoustic logging methods (OBI and ABI) the boreholes were logged at the Rožná Mine. Oriented recording of the walls was performed using optical television (OPTV - Optical TeleViewer) in the horizontal borehole (VRT-H). The optical recording was supplemented by the acoustic television record (HiRAT - High Resolution Acoustic Televiewer) in the down borehole (VRT-U). The measured oriented records by OBI and ABI methods were processed and evaluated in WellCAD software for logging data processing. Based on the evaluated structural data, a structural cross-section was constructed, which was the background material for correlation with geophysical data.
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Determination of physical-mechanical properties of rock for the purpose of rock mass stress calculation based on CCBO probes measurements
Staš, Lubomír ; Waclawik, Petr ; Souček, Kamil ; Vavro, Martin
To measure the primary stress of the rock mass, the overcoring method was used using a compact conical probe CCBO. A total of four stress measurements were performed in a metamorphic rock mass formed by biotite gneiss, in a horizontal borehole marked VRT-H. For the purposes of calculating the size of the main rock mass stress components, it is necessary to know the basic physico-mechanical properties of the rock mass at the measurement site. For this reason, test specimens were prepared from the drill core, which were subsequently tested on the ZWICK 1494 mechanical press. The research report describes the samples, methodological procedures and results of physico-mechanical properties.
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Assessment of primary rock mass stress by overcoring method using CCBO probes, Mine Rožná
Staš, Lubomír ; Waclawik, Petr ; Souček, Kamil ; Vavro, Martin ; Kukutsch, Radovan ; Nohejl, Zdeněk ; Rutar, Tomáš
The measurement of the stress state of the rock mass was performed on the 20th level of the liquidated uranium mine Rožná. This site was selected as one of the possible test sites of the planned geotechnical and geophysical methods. As part of the measurements, a series of four measurements of the 3D stress tensor were carried out within the sub-horizontal (approx. + 5 °) borehole with a diameter of 76 mm. To measure the primary stress of the rock mass, the overcoring method was used using a compact conical probe, developed at the Institute of Geonics AS CR, v.v.i. in collaboration with the Japanese University of Kumamoto under the original name Compact Conical ended Borehole Overcoring method (CCBO). The research report summarizes the results of the performed measurements.
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Stress state rock mass monitoring ahead of longwall No. II/501/C, Mine Staszic-Wujek, PGG, Poland -Project RFCS DD-MET
Waclawik, Petr ; Kukutsch, Radovan ; Staš, Lubomír ; Souček, Kamil ; Vavro, Leona ; Vavro, Martin ; Kubina, Lukáš ; Schuchová, Kristýna
For designing precisely the reinforcement of mine gate and reinforcing underground structures in general, knowing stress and deformation states in the rock massive in the immediate vicinity of these mine works as precisely as possible is absolutely decisive. In order to verify the rock mass stress state and its changes induced by longwall mining, the monitoring of rock mass stress changing in connection with the mine out of the coal seam No. 501, longwall face No. II/501/C in the Mine Staszic-Wujek, Poland, was suggested. The aim of the contractual research was the realisation and interpretation of the rock stress state monitoring using the CCBO (Compact Conical ended Borehole Overcoring method) and CCBM (Compact Conical ended Borehole Monitoring method) probes in the forefield of mentioned longwall face within geotechnical station. To verify stress monitoring, the survey of the state of the longwall gate was carried out using a pulse 3D scanner. The purpose was to capture deformation changes ahead of the advancing longwall face, specifically, at five stages in the ± 20 m section on each side from the installed geotechnical station.
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Structural mapping of exploration geotechnical boreholes walls within 2nd phase – Decline
Waclawik, Petr ; Schuchová, Kristýna ; Kukutsch, Radovan ; Georgiou, Lucie
Structural-geological analysis, i.e. fracturing assessment of the walls of geotechnical boreholes (CIS38 and CIS39) within the projected Decline in lithium exploratory area was carried out on the basis of optical (OPTV) and acoustic televiewer (HiRAT) records evaluation. HiRAT and OPTV probes are part of the Robertson Geologging logging equipment. The apparatus has an electric winch with a four core logging cable, which transmits the data recorded by the probes via a data logger to a computer. The spatial data obtained from interpretation of the geotechnical boreholes records were structurally analysed. The submitted research report comprehensively summarises the findings obtained from the structural mapping of geotechnical boreholes. On the basis measured data the rock mass quality evaluation of boreholes walls were additionally done. The complex data have been allowed very precise analysis of rock mass structural conditions, which are necessary for design of opening mine working.
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