Experimental Study on Microwave Assisted Hard Rock Cutting of Granite

Hartlieb, Philipp; Grafe, Bruno

doi:10.1007/s00501-016-0569-0

Cited by 53 publications

(6 citation statements)

References 14 publications

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“…Lu et al [57] used the power of 2.1kW microwave radiation Chifeng basalt, and the use of the reduced-scale SP3-I TBM cutter to complete the rock-breaking test research, the results show that microwave radiation makes the rock-breaking volume increased significantly, disc cutter force and rockbreaking specific energy significantly reduced. Through comparative analysis, the simulation study has the same rule of change before and after microwave radiation, but due to the adjustment of microwave power and radiation time makes the input of microwave energy change, and the improvement effect in the hob force, rock-breaking, and rock-breaking specific energy is different [63] .…”

Section: Discussionmentioning

confidence: 99%

Study on Microwave-assisted TBM Double-edged Cutter Rock-breaking Efficiency and its Positional Relationship

Wen,

Du,

Kong

et al. 2024

Eksploatacja i Niezawodność – Maintenance and Reliability

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In this study, based on a microwave test, the discrete element program (PFC) is used to establish a microwave-assisted disc cutter rock-breaking model and explore the influence law of the positional relationship between microwave radiation and disc cutter penetration on rock-breaking efficiency, and the results show that: The improvement of the positional relationship has a significant effect on improving the rock-breaking efficiency, and the double-edged cutter reaches and minimum rock-breaking specific energy when breaking the rock in the center position with a waveguide spacing of 90 mm and in the inner and outer positions with a waveguide spacing of 150 mm; When the waveguide spacing is 150mm, the double-edged cutter with cutter spacing of 110mm, 130mm, and 190mm have their advantages in rock-breaking efficiency and economic benefits, which should be selected according to the actual needs of the project. The follow-up research should also fully consider the rock type, microwave parameters, cutter profile, engineering environment, and other factors for in-depth investigation.

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Section: Discussionmentioning

confidence: 99%

Study on Microwave-assisted TBM Double-edged Cutter Rock-breaking Efficiency and its Positional Relationship

Wen,

Du,

Kong

et al. 2024

Eksploatacja i Niezawodność – Maintenance and Reliability

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“…When the absorption properties of the rock are good (e.g. in basalt) this can even lead to spallation at the surface (Hartlieb 2013). Although this is spectacular, it does not lead to a deeper going or widely spread network of cracks.…”

Section: Microwave Crackingmentioning

confidence: 99%

Theoretical Investigations on the Influence of Artificially Altered Rock Mass Properties on Mechanical Excavation

Hartlieb

Bock

2017

Rock Mech Rock Eng

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guaranteeing the access to mineral deposits and for extracting the valuable minerals from these deposits. Mechanical excavation tools like full-face tunnel boring machines and roadheaders use either discs or conical picks for applying the required forces into the rock mass. The efficiency of the processes is mainly governed by the mechanical properties of the rock type, especially strength and abrasivity. Roadheaders are limited by a uniaxial compressive strength of 150 MPa, TBMs by roughly 300 MPa. In particular, the development of underground mines furthermore requires a high flexibility of the used equipment which is mainly characterised by the turning radius of the machine. The rather simple relationship is the harder the rock, the bigger the machine, the lower the flexibility.In order to improve the performance of their machines, most machine manufacturers on the market have introduced new machine concepts recently. Many of which change the cutting principle and apply the so-called undercutting technology (e.g. Aker Wirth "Mobile Tunnel Miner", Atlas Copco "Mobile Miner", Joy Mining "Oscillating Disc Cutter", Caterpillar "Rock Straight system" and Sandvik "MX650" (Sifferlinger et al. 2017)).In addition to changing the machine concept, the goal of extended research activities all over the world during the last decade is focussed on overcoming the highlighted restrictions. The major focus is set on artificially altering the rock mass properties in order to ease the machines' life by reducing the UCS and rock mass rating. This can be done by introducing cracks and/or slots in the rock mass which help the subsequent cutting process with a conical tool. The technologies under consideration are high-power lasers Parker et al. 2003;Graves and Bailo 2005), microwaves (Toifl et al. 2017; Hartlieb and Grafe 2017), high-pressure water jets (Ciccu and Grosso 2010;Miller 2016) and activated tools (Keller and DrebenstedtAbstract This study presents a theoretical analysis of the influence of the rock mass rating on the cutting performance of roadheaders. Existing performance prediction models are assessed for their suitability for forecasting the influence of pre-damaging the rock mass with alternative methods like lasers or microwaves, prior to the mechanical excavation process. Finally, the RMCR model was chosen because it is the only reported model incorporating a range of rock mass properties into its calculations. The results show that even very tough rocks could be mechanically excavated if the occurrence, orientation and condition of joints are favourable for the cutting process. The calculated improvements in the cutting rate (m 3 /h) are up to 350% for the most favourable cases. In case of microwave irradiation of hard rocks with an UCS of 200 MPa, a reasonable improvement in the performance by 120% can be achieved with as little as an extra 0.7 kWh/m 3 (= 1% more energy) compared to cutting only.

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“…Studies on basalt revealed significant microcrack differences based on power levels and distances from the antenna, with longer exposures leading to more severe cracks [41]. Subjecting granite samples to microwave treatment significantly reduced the peak and average cutting forces (~10% reduction in average cutting force from untreated to irradiated parts) [42]. It was demonstrated that the resulting temperature and stress level vary strongly depending on the input microwave irradiation parameters [43].…”

Section: Introduction 1the State Of the Artmentioning

confidence: 99%

The Comminution of Chert Gravel by Microwave Irradiation

Tzibulsky,

Frid

2024

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Chert, a by-product rock of sand quarrying, has historically posed economic challenges for aggregate production, resulting in significant “waste” accumulation in quarries. Our study investigates the effect of microwave irradiation on the mechanical properties of chert gravel, a mineralogically homogenous material composed of fine quartz grains. The results, which demonstrate that increased irradiation time leads to a substantial decrease in chert gravel strength (by a factor of 4–6 for 2.5 min of irradiation), underscore the potential impact of this research on comminution processes. With quenching altering the fractional content of the samples after the crushing test, reducing the Gravel-to-Sand ratio, this study is driven by the promising potential of crushed chert gravel as a pivotal aggregate within the concrete and asphalt industries, offering a practical solution to their material needs. The urgent need to rehabilitate previously utilized quarry areas, offering an environmentally beneficial solution for which we all should be responsible, motivated the present study.

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Experimental Study on Microwave Assisted Hard Rock Cutting of Granite

Cited by 53 publications

References 14 publications

Study on Microwave-assisted TBM Double-edged Cutter Rock-breaking Efficiency and its Positional Relationship

Study on Microwave-assisted TBM Double-edged Cutter Rock-breaking Efficiency and its Positional Relationship

Theoretical Investigations on the Influence of Artificially Altered Rock Mass Properties on Mechanical Excavation

The Comminution of Chert Gravel by Microwave Irradiation

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