Department of Destructional and Constructional Geotechnics

Head of the department: Ing. Edita Lazarová, PhD.

The research group of the Department of Destructional and Constructional Geotechnics (DDCG) offers a wide range of high level knowledge and experience on the processes running in cutting and drilling of rocks and concrete, focused from small-diameter rotary drilling up to the large-diameter tunnelling using full-face tunnel boring machines (TBM). Major expertise of the group is in the study of both key- and side-effects of drilling process such as acoustic and vibration signals for optimization of rock cutting process control as well as in investigation of interactions in the system drilling bit-rock.

RESEARCH FOCUS

Research in the DDCG of IGT SAS is focused on the investigation of the rock breaking by mechanical means (cutting, drilling, excavation, tunneling) covering wide range of aspects:

• Identification of the main factors affecting and determining the rock cutting mechanism.
• Monitoring and optimization of rock cutting processes in the interaction between the drill bit-rock.
• Development of inverse and non-standard methods for assessment of rock mass conditions and process effectiveness. Investigation of energy distribution  in  rock cutting process and accompanying phenomena (vibrations, noise, heat).
• Determination of rock strength properties for assessment of parameters in mechanical and non-mechanical
  rock and concrete cutting (i.e. point load test strength, indentation strength, uniaxial compressive strength, Schmidt rebound hardness, etc.).
• Assessment of rock and concrete abrasiveness by different methods and standards for rock quality assessment.
• Study of stress distribution in the cutting tool and rock for the purposes of the design of cutting tools, application of the patterns of fracture mechanics into rock mechanics in rock cutting and drilling processes.
• Application of the means of artificial intelligence, fuzzy methods and frequency analysis in rock cutting.
• Compaction of industrial waste materials and biomass.

There have been two main streams of the DDCG research in recent years:

1. Small-diameter rotational drilling of rocks

The Department designed and constructed an experimental laboratory horizontal drilling rig installed in the premises of the IGT SAS. The drilling rig allows drilling with core-drilling bits up to 46 mm diameter. Accompanying phenomena, such as noise (acoustic signal) and vibrations induced during the drilling have been analyzed in time and frequency domains. The main purpose of the research is to identify the determining variables for the control of rock drilling process and to analyze the possibilities of the rock type identification during the drilling using the methods of artificial intelligence.

2. Large-diameter and full-profile excavation of tunnels by TBM

The research of TBM related processes has been focused on the full-profile excavation in complex and difficult geological and geotechnical conditions with a view to identify the properties of such system, evaluation of cost-effectiveness of the TBM excavation and the prediction of the TBM performance. Quantitative and qualitative evaluation of the TBM tunneling process based on monitored data provided the development of the inverse methods of the rock mass properties assessment. Recently, a fuzzy supporting system for inclusion of the effect of geological structures on TBM advance rate has been designed.

EXPERIENCE

DDCG researchers designed and assembled an experimental laboratory drilling rig, which allows to carry out the research in the field of rotary drilling of rocks. The drilling rig serves also for master and PhD students postgraduate students of Faculty of mining of Technical University, Kosice during their practical courses. The experimental research resulted in development of new qualitative techniques for the evaluation of rock mass as well as for improvement of efficiency of rock cutting process using advanced mathematical, statistical and artificial intelligence means.

Research activities led by Prof. Sekula, Prof. Krupa and Dr Krepelka resulted in the development of advanced monitoring and optimization systems for industrial drilling rigs (ZIF1200, SKB5), industrial shaft drilling machines (Bespadrill P1), and for industrial full-face tunnel boring machines (Wirth TB II-330H, RS 24-27H, Demag 55HA, RS 37-40H, Wirth TB-II-330H/M, Voest Alpine ATB 35HA), which were successfully deployed in Slovak mining and tunnelling industry.

DDCG team developed automated systems for monitoring and optimization of rock cutting process (e.g. WORS, IKONA) for lab scale rotary drilling and for in-situ tunnel excavation applications. The WORS and IKONA methods allow to describe the energy- and strength characteristics of the rock mass from operational parameters of TBM. IKONA delivered inverse determination of rock mass strength properties based on monitored process variables of the excavation regime using the mathematical models. Such unique outcomes and methods enable to characterize the rock mass in the very detail and to predict the dangerous failure zones in real-time during the TBM tunneling.

DDCG team possess a wide experience with transfer of scientific knowledge to industry. Our monitoring and optimization systems were successfully applied in mining applications and in excavation of exploratory galleries of the highway tunnels Branisko and Višňové in Slovakia. The team elaborates the expert reports on rock properties assessment based on commercial orders from industry on a regular base.

RESEARCH INFRASTRUCTURE

Experimental devices

• experimental horizontal laboratory drilling rig for rotary drilling with bits of diameters up to 70 mm with automated systems of control and monitoring, designed and constructed at the IGT SAS,
• 4-channel dynamometer and multichannel amplifier Kistler for multi-component force measurement during drilling (3 force components and torque),
• accelerometers and automated system Adash 3900-II for monitoring of the vibration acceleration during drilling, installed on the drilling rig.

Equipment for characterization of strength, deformation and technological properties of rocks

• experimental press INSTRON 1000 RD (load up to 5 MN) for testing the strength and deformation characteristics of rocks,
• Point Load Tester PLT-100, GCTS for measurement of the point load strength of rocks,
• Schmidt hammer SilverSchmidt PC/N, Proceq for measurement of rock rebound hardness correlated to the UCS and standardized according to the European standard EN 12504-2: 2012,
• abrasionmeter CERCHAR, ErgoTech for measurement of rock abrasiveness after CERCHAR methodology,
• abrasionmeter for measurement of rock abrasiveness, designed and constructed at IGT SAS according to the Slovak technical norm ON 441121,
• abrasionmeter for determination of rock abrasiveness according to the methodology LCPC, designed and constructed at IGT SAS.

Equipment for preparation of testing samples

• circular saws for the preparation of rock samples,
• grinders and sanders for preparation of rock samples.

Experimental data processing software and hardware

• automated systems for monitoring of laboratory experiments and for the field in-situ conditions,
• software application for management, visualization, data collection and archiving of data from laboratory drilling rig,
• software DynoWare 5825 for the monitoring, analysis and visualization of signals from Kistler dynamometer,
• vibro-diagnostic software DDS 2007 for analysis of vibration signals monitored by accelerometers,
• IBM/Oracle database server for storage and distribution of experimental data from the laboratory drilling rig,
• MATLAB software for mathematical modelling and analysis, Simulink, Fuzzy Logic Toolbox, MATLAB Builder for Excel, MATLAB Compiler, Signal Processing Blockset, Signal Processing Toolbox, Statistics Toolbox Version, System Identification Toolbox,
• remote access to powerful computing systems MATLAB and COMSOL Multiphysics in national data centre project for science and research, and national infrastructure for technology transfer in Slovakia – CVTI,
• Adobe CS6 Design software for image processing and image analysis,
• OriginPro 9.0 software for analysis of experimental data,
• Analyse-It for Excel – statistical software,
• Microsoft Office,
• computer infrastructure based on Microsoft Windows,
• LAN, 1 gigabit Ethernet, access via Slovak Academic Network SANET.

 
RESEARCH STAFF