Predicting powder factor in mixed-face condition: development of a correlation based on investigations in a tunnel through basaltic flows

Chakraborty, A.K.; Jethwa, J.L.; Dhar, Biswajit

doi:10.1016/s0013-7952(96)00117-2

Cited by 8 publications

(3 citation statements)

References 3 publications

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“…If the geo-mechanical properties of the constituting formations of a tunnel are quite different, the stress energy utilisation and resulting fragmentation are adversely affected. Chakraborty et al (1996b) suggested an increase of specific charge by a per cent equal to ten times the number of contact surfaces.…”

Section: Rock Mass Damagementioning

confidence: 99%

Special Tunnel Blasting Techniques for Railway Projects

Ramulu¹

2012

Infrastructure Design, Signalling and Security in Railway

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Excavations of tunnels are common features in mining and civil engineering projects. In absence of initial free face, solid blasting method is employed for excavation of tunnels, drifts and mine roadways, which have many similarities in configurations and in different cycles of operation followed during excavation. A greater proportion of world's annual tunnel advance is still achieved by drilling and blasting. In spite of inherent disadvantages of damaging the rock mass, drilling and blasting has an unmatched degree of flexibility and can overcome the limitations of machine excavations by Tunnel Boring Machine (TBM) or road headers. In spite of no major technical breakthrough, the advantages like low investment, availability of cheap chemical energy in the form of explosives, easy acceptability to the practicing engineers, the least depreciation and wide versatility have collectively made the drilling and blasting technique prevail so far over the mechanical excavation methods.Since tunnels of different sizes and shapes are excavated in various rock mass conditions, appropriate blast design including drilling pattern, quantity and type of explosive, initiation sequence is essential to achieve a good advance rate causing minimal damage to the surrounding rock mass. The cost and time benefit of the excavation are mostly decided by the rate of advance and undesired damage.Excavation of tunnels, except in geologically disturbed rock mass conditions, is preferred with full face blasting. It is common to excavate large tunnels of 80-90 m 2 cross-section in sound rock masses by full face in a single round. However, tunnels larger than 50m 2 crosssectional area driven through incompetent ground condition are generally excavated in smaller parts.

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Section: Rock Mass Damagementioning

confidence: 99%

Special Tunnel Blasting Techniques for Railway Projects

Ramulu¹

2012

Infrastructure Design, Signalling and Security in Railway

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“…Several drawbacks constrain the conventional methods for predicting powder factor in rock blasting, including their reliance on oversimplified assumptions, limited accuracy in heterogeneous geological environments, and inability to account for changing site conditions [ 7 , 16 ]. These approaches often overlook the influence of mixed geological formations on the powder factor [ 17 ] and may not adequately evaluate the risk of blasting-induced rock damage [ 18 ]. In order to overcome these constraints, it is necessary to employ a more extensive and precise approach that incorporates various characteristics of the rock mass, the materials used for blasting, and the geometry of the blasting process.…”

Section: Introductionmentioning

confidence: 99%

Explosive utilization efficiency enhancement: An application of machine learning for powder factor prediction using critical rock characteristics

Olamide Taiwo,

Gebretsadik,

Abbas

et al. 2024

Heliyon

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“…Chakraborty et al (1994) found that the powder factor in tunnels can be correlated with the Barton's rock mass quality (Q) of the tunnel rock mass. Chakraborty et al (1997) developed a correlation allowing the prediction of the powder factor in the tunnel, considering the uniaxial compressive strength, the Q-value, the thickness of each formation, and the effects produced by interformational contact surfaces. Systematic studies that synthesize the geological conditions for the purpose of estimating the powder factors, however, have been few and far between in Korea.…”

Section: Introductionmentioning

confidence: 99%