Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Assessment of Rock Abrasiveness by Various Methods for Prediction of Drilling Bit Wear
Labaš, Milan (Institute of Geotechnics of Slovak Academy of Sciences) | Ivanicová, Lucia (Institute of Geotechnics of Slovak Academy of Sciences) | Feriancíková, Katarína (Institute of Geotechnics of Slovak Academy of Sciences) | Kruláková, Mária (Institute of Geotechnics of Slovak Academy of Sciences) | Lazarová, Edita (Institute of Geotechnics of Slovak Academy of Sciences)
Abstract Rock abrasiveness immediately affects the wear of cutting indenters of the drilling bits. Rock abrasiveness is ability of rock to wear down the cutting tool during the interaction between the indenter and the rock in the mechanical rock cutting process. There are several methods for estimating the abrasiveness of rocks and minerals. One of the methods of rock abrasiveness testing is the method according to the Slovak technical norm ON 44 1121. The concept of the test resides in the determination of weight loss of normalized metal pins during its circular motion on a surface of a tested rock sample under constant thrust force. The abrasiveness according the norm ON 44 1121 will be termed as „pin rock abrasiveness" FV. The experimental results of the determination of FV abrasiveness were compared to the values of the CERCHAR Abrasivity Index (CAI). 1 The Effect of Anisotropy on Rock Strength Assessment 1.1 Defining "anisotropic behaviour" Mechanical cutting of rocks is affected by rock properties, which are represented by several mechanical and technological parameters. Rock abrasiveness belongs to such parameters. Rock abrasiveness is ability of rock to wear down the working tool during the interaction between the working indenter and the rock in the mechanical rock cutting process. The cutting indenter is worn down during the interaction, which changes its geometric dimensions, causing the enlargement of a contact area between the tool and the rock surface. Change of these dimensions leads to the change of the advance rate of the tool and the specific cutting energy. Rock abrasiveness immediately affects the wear of cutting indenters of the tool. The wear of indenter exhibits in the decrease of the instantaneous drilling rate and in the increase of the specific cutting energy, which both directly affect the economic issues of mechanical cutting. The applied regime of rock cutting affects the wear of indenter substantially. The smallest intensity of wear occurs in the cutting regime, which is the argument of minimum of specific cutting energy. In such regime, the indenter should reach the greatest lifetime, if considering only the effect of wear (Krúpa & Lazarová 2008). Intensity and wear rate depend on several simultaneously acting factors in the interaction of the indenter and the rock. The most important factors are:
- Geology > Rock Type (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
Application of TBM Monitored Data for Detailed Description of Rock Mass Parameters and Fast Determination of TBM Excavation Efficiency
Lazarová, Edita (Slovak Academy of Sciences) | Krúpa, Vítazoslav (Slovak Academy of Sciences) | Kruláková, Mária (Slovak Academy of Sciences) | Ivanicová, Lucia (Slovak Academy of Sciences)
Abstract The paper presents the results of the research in the field of mechanical rock cutting by disc cutters of the tunnel boring machines. Investigation of rock cutting mechanism was focused on the interaction of the system cutter-rock with a view to identify the dominant characteristics and parameters of this system. The theoretical aspects of rock cutting by disc cutters were verified using the comparison of the monitored data from tunnels with data from conventional engineering-geological survey. Apart from analytical and statistical methods, also the means of artificial intelligence were applied, which enabled to investigate the mutual relations between parameters of the excavation process determined by application of various methods. Acquired results enabled to complement and specify the results of conventional geological, engineering-geological hydrogeological and geotechnical survey. The paper also delivers a novel solution to the problem of optimization of the energy consumption of the TBM. 1 Introduction The research of mechanical rock cutting has been the main objective of the research group at the Institute of Geotechnics, Slovak Academy of Sciences (IGT SAS). After the first stage of research performed in laboratory conditions using the experimental laboratory drilling rig, the investigation moved to the in-situ conditions of the underground constructions. Several series of monitoring and optimizing systems of the tunnel boring machines (TBM) performance were developed at the IGT, installed at various TBMs, such as WIRTH TB-II-330H/M deployed in excavation of the exploratory gallery of Branisko motorway tunnel, and Voest-Alpine ATB 35HA driving the exploratory gallery of the Višnové motorway tunnel. The monitoring systems provided data acquisition of TBM parameters, scanned in 2-seconds intervals, which were filtered and used for subsequent calculation of relevant parameters for assessment of the tunnelling process, the values were then averaged for approximate 25 cm long tunnel sections. The sampling period of 2 seconds enabled to acquire the data with density corresponding to the continuous record depending on the TBM's advance rate. One single revolution of the TBM cutterhead produced 2–3 values of regime parameters. Such outputs were archived along with the information from engineering-geological prospecting, thus forming an extensive database for further analyses and theoretical investigation. Database processing involved conventional mathematical and statistical methods, as well as the alternative methods, such as means of artificial intelligence.
- Machinery > Industrial Machinery (0.54)
- Energy > Oil & Gas > Upstream (0.49)