Effect of pick blunting on cutting performance for weak moderate rocks

Download

index.pdf

Date

2010

Author

Doğruöz, Cihan

Metadata

Show full item record

Item Usage Stats

215
views

290
downloads

The laboratory cutting specific energy is widely used to estimate the cuttability of rocks by a roadheader fitted with sharp picks. Sharp picks on the other hand become blunt due to wear in time and require replacement. Although it is known that the pick blunting affects adversely the rock cuttability, no study exists to show the relationships between the degree of pick wear and the cutting specific energy obtained by standard cutting tests. In this study, standard cutting tests were carried out on different rock types, with picks having varying degrees of blunting. The relationships between wear flats and the cutting forces, specific energies and size distribution for various rock properties such as uniaxial compressive strength, tensile strength, cone indenter number, shore hardness, schmidth hammer hardness, density and grain size were established. The mean cutting force and the cutting specific energy have been found to increase 2-3 times and 4-5 times respectively with 4 mm wear flat as compared to sharp picks as the strength and density of rocks increase. No relation exists between mineral grain size and the cutting performance. A definite relation could not be established between the wear land and the size distribution of the product. Charts have been produced to predict critical wear flats for different rock property values considering 25 MJ/m³ as the limiting specific energy above which poor cutting performance occurs. Nine prediction models have been developed by statistical analysis to estimate the laboratory cutting specific energy from various rock properties and wear rates.

Subject Keywords

Civil engineering., Rock mechanics.

URI

http://etd.lib.metu.edu.tr/upload/12612614/index.pdf
https://hdl.handle.net/11511/20032

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

The effect of shape memory alloys on the ductility of exterior reinforced concrete beam-column joints using the damage plasticity model Halahla, Abdulsamee M.; Abu Tahnat, Yazan B.; Almasri, Amin H.; Voyiadjis, George Z. (Elsevier BV, 2019-12-01) Using shape memory alloys (SMA) bars can significantly enhance the ductility of exterior reinforced concrete joints, where they can replace the conventional steel reinforcement. This research focuses on studying the effect of using SMA on the ductility capacity of exterior reinforced concrete beam-column joints at different column axial load levels. Finite element analysis was carried out and compared with the experimental results from the literature for verification purposes, and both were compared with th...
Effect of Weathering Tests on Microfracture Properties of the Massive and Vesicular Basalts DURSUN, FELAT; Topal, Tamer (2020-10-03) Petrographic investigations not only provide knowledge on the mineralogical state and provenance of rock materials, they also can be used as a strong tool for evaluating its weathering potential and durability. It is known that the type, amount, dimension, orientation and density of cracks have a great influence on the weathering of the stone material. The chemical agents, for instance, that cause weathering in rock materials, use cracks to penetrate their depths. This study aims to understand how accelerat...
The effect of group behavior on the pull-out capacity of soil nails in high plastic clay Akış, Ebru; Bakır, Bahadır Sadık; Department of Civil Engineering (2009) Soil nailing technique is widely used in stabilizing roadway and tunnel portal cut excavations. The key parameter in the design of soil nail systems is the pull-out capacity. The pull-out capacity of the soil nails can be estimated from the studies involving similar soil conditions or can be estimated from the empirical formulas. Field verification tests are performed before the construction stage in order to confirm the parameter chosen in the design of soil nailing system. It is reported in the literature...
Effects of Zinc Borate on the Flame Retardancy Performance of Aluminum Diethylphosphinate in Polyamide-6 and its Composites Polat, Özlem; Kaynak, Cevdet (Carl Hanser Verlag, 2019-03-01) In this study, the flame retardancy contribution of zinc borate when used together with a traditional flame retardant (aluminum diethylphosphinate compound) was investigated for neat polyamide-6 and for 15 wt% short glass fiber reinforced composite. Melt mixing with twin-screw extrusion was the compounding method while injection and compression molding were the shaping methods of specimens. Three different flammability tests (limiting oxygen index, UL-94 vertical burning, mass loss calorimetry) indicated th...
A numerical study on response factors for steel wall-frame systems Arslan, Hakan; Topkaya, Cem; Department of Civil Engineering (2009) A numerical study has been undertaken to evaluate the response of dual systems which consist of steel plate shear walls and moment resisting frames. The primary objective of the study was to investigate the influence of elastic base shear distribution between the wall and the frame on the global system response. A total of 10 walls and 30 wall-frame systems, ranging from 3 to 15 stories, were selected for numerical assessment. These systems represent cases in which the elastic base shear resisted by the fra...

Citation Formats

C. Doğruöz, “Effect of pick blunting on cutting performance for weak moderate rocks,” Ph.D. - Doctoral Program, Middle East Technical University, 2010.