Control of rock cutting efficiency by muck size

Tunçdemir, H.; Bilgin, N.; Copur, Hanifi; Balcı, Cemal

doi:10.1016/j.ijrmms.2007.04.010

Cited by 111 publications

(36 citation statements)

References 7 publications

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“…The TBM could in fact be considered as a primary breaker in the rock handling process for shotcrete or concrete production (Tuncdemir et al, 2008). The geometric characteristics of the excavated material is affected by the excavation method that is used; muck obtained from Tunnel Boring Machines (TBMs) is more difficult to reuse for concrete than muck obtained from drill and blast excavations, as the typical form of the granules that are produced is lamellar and these grains tend to form horizontal planes during the concreting phase (Innaurato et al, 2007).…”

Section: The Tbm As First Breakermentioning

confidence: 99%

An Applied Study on the Debris Recycling in Tunnelling

Anas¹

2012

American Journal of Environmental Sciences

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Problem statement:A simple calculation has shown what the impact of muck created during the construction of a hypothetical 50 km long and 100 m 2 cross section tunnel could be on the environment: around 8 million cubic meters would have to be discharged as waste material. One solution to such a problem could be to recycle (almost a part) the earth material, that is, the muck and debris that are excavated from the tunnel face. Approach: In order to verify the possibility of using some different breakers from the ones used in the handling plant on the studied tunnel-access, some tests were performed in the DITAG laboratory at the Politecnico DI Torino. Results and Conclusion: Different cut dimensions were considered in the recycling of the muck material from the tunnel excavation using TBMs. The obtained material, mixed with natural sands and gravels according to various hypotheses, corresponds to the dimensional requirements for the shotcrete and concrete aggregates. The optimal solution should be the mixture of the best fines produced by TBM, the products of the broken rock and some percentage of natural sands and gravels. The final choice will depend on economic factors and obviously also on the particular features in the work sites.

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Section: The Tbm As First Breakermentioning

confidence: 99%

An Applied Study on the Debris Recycling in Tunnelling

Anas¹

2012

American Journal of Environmental Sciences

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“…The step distance to the adjacent groove is s. It is assumed that coupling occurs between the existing groove and the new groove, i.e., that a shear plane occurs from origin A to point C. The shear plane between the coupled grooves is not necessarily approximately planar [12], If, in order to preserve compatibility with Eq. (1), we assume that the distribution of the resultant force on line AC obeys a power law, we obtain the following expression: ( 5 ) Here is the distance from origin A toward C. The integral of p from A to C must be in equilibrium with the resultant force F, so we can set the integration of Eq. (5) from = 0 to s equal to F, obtaining: ( 6 ) Eliminating p 0 from Eqs.…”

Section: (When There Is An Adjacent Groove)mentioning

confidence: 99%

“…It is well known that the larger the debris, the greater the efficiency of the excavation [2,3]. Debris size and shape become criteria for whether or not it can be reused; for example, as the aggregate in concrete [4,5]. However, knowledge about the size and shape of debris is generally passed down at individual work sites, and little basic research has been conducted.…”

Section: Introductionmentioning

confidence: 99%

Size and Shape of TBM Debris Estimated by the Nishimatsu's Cutting- Resistance Equation

Okubo¹,

Fukui²,

Chen³

2010

TOCIEJ

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Information concerning the size and shape of tunnel boring machine (TBM) debris is essential for designing efficient loading, hauling and dumping systems for TBM excavation. It is also very important in deciding how to recycle the TBM debris. However, only very limited information is available at present, and theoretical or calculation methods to estimate the size and shape are still open to discussion. In this paper, the size and shape of TBM debris are estimated by the well-known Nishimatsu's equation that is usually applied to roadheaders or shield-type machines with chisel bits. In this study, the equation was applied to the case of TBM excavation with disc cutters in which the shear failure or plane extends from a new groove to an adjacent pre-existing one. The estimated size and shape of TBM debris were found to be consistent with the measured results. Side forces applied to a disc cutter and the resultant stress on the cutter were considered. The maximum debris size encountered in tunnel excavation was also discussed assuming that it followed the Gumbel distribution. The results suggest that the proposed approach based on Nishimatsu's equation shows potential for future study.

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“…Cutting efficiency is another important factor to determine the production and economics of rock cutting machinery [177]. An indicator of the efficiency of mechanical excavators [4,78,80] is specific energy which is defined as the work done per unit volume of rock cut.…”

Section: Introductionmentioning

confidence: 99%

“…It can be used to assess the rock cuttability and excavation performance for a particular mechanical excavator. Size distribution of the chips generated during rock cutting process is also closely related with rock cutting efficiency, and may provide some information on rock fragmentation mechanisms [177]. It is therefore very important to investigate the chip size distribution and specific energy under different cutting conditions.…”

Section: Introductionmentioning

confidence: 99%

A study of rock cutting with point attack picks

Shao¹

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Hard rock mining is currently carried out by drill-and-blast. With the increasing demand for automated, selective and remote mining, the industry hopes to replace conventional drill-and-blast with mechanical excavation. Modern mining machines have sufficient power for cutting hard rocks.The 'bottleneck' which limits the use of mechanical excavation for hard rock mining is the cutting tool wear. Rock cutting tools usually use tungsten carbide (WC) tipped picks. The WC tipped picks are effective and adequate for cutting relatively soft rocks, but unsuitable for hard rocks. To address this issue, CSIRO has developed Super Material Abrasive Resistant Tool (SMART*CUT), aiming at providing an effective cutting tool for hard rock mining. The key feature of the SMART*CUT technology is replacing the conventional WC with thermally stable diamond composite (TSDC) as the cutting tip of the pick. The main advantages of the TSDC tipped picks include (a) good thermal stability, (b) high wear resistance and (c) the ability to mine relatively hard deposits in comparison with the WC tipped picks. The disadvantage of the TSDC tipped picks is their low fracture toughness. To optimise the application of the TSDC tipped picks, this work aimed to improve the understanding of the rock cutting process and mechanisms, in particular to gain a better insight into the interaction between tools and rocks through systematic experimental and numerical studies. The rock cutting processes with the TSDC and WC tipped point attack picks were comprehensively investigated in terms of cutting force, specific energy, tool tip temperature and cutting chips.A study of rock cutting was systematically carried out using the Taguchi method to determine the effects of the cutting parameters on the performance of the TSDC tipped picks. The signal-to-noise (S/N) ratios and the analysis of variance (ANOVA) were applied to investigate the effects of the depth of cut, attack angle, spacing and cutting speed on the mean cutting, normal and bending forces involved in the rock cutting process. The statistical significance of process factors was determined and the optimum parametric combinations were successfully identified. Furthermore, the multiple linear regression (MLR) and artificial neural network (ANN) techniques were adopted to develop the empirical models for predicting the mean cutting and normal forces with the TSDC tipped picks. The established empirical force models showed good predictive capabilities with acceptable accuracy. The ANN models offered better accuracy and less deviation than the MLR models.The pick cutting temperature involved in rock cutting was measured using thermal infrared imaging and embedded thermocouple techniques. The temperature distribution in the cutting area was acquired by using a thermal infrared camera with high speed imaging rates. The results showed that II the TSDC tipped picks generated much lower thermal energy and much fewer sparks than the WC tipped picks. The temperature at the pick tip in the contact area wi...

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Control of rock cutting efficiency by muck size

Cited by 111 publications

References 7 publications

An Applied Study on the Debris Recycling in Tunnelling

An Applied Study on the Debris Recycling in Tunnelling

Size and Shape of TBM Debris Estimated by the Nishimatsu's Cutting- Resistance Equation

A study of rock cutting with point attack picks

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