Advance per Blast (Pull)
Calculate the effective advance per blast (pull) in drill-and-blast tunnelling, advance = L·η, from the drilled hole length L (m) and the blast efficiency η (0-1). Not all drilled depth converts to advance: part is lost because the hole bottoms do not always break fully, leaving a 'socket'. Typical efficiency is 85-95% — depending on the blast pattern, rock type and execution. Advance per blast, times the cycles per day, sets the rock face productivity. Maximizing it reduces cycles and schedule, but very long holes lose drilling accuracy and efficiency. Enter the drilled length and the blast efficiency.
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Avanço por disparo (pull)
Na escavação de túneis em rocha pelo método de perfuração e desmonte (drill & blast) — o método mais antigo e ainda dominante em rocha dura — cada ciclo consiste em perfurar dezenas de furos na frente, carregá-los com explosivo, detonar, ventilar, remover o material desmontado (mucking) e suportar a nova seção. O avanço por disparo (pull) é quanto o túnel efetivamente progride a cada detonação: avanço = L·η, o comprimento perfurado dos furos L vezes a eficiência do fogo η. O detalhe importante é que η < 1: nem toda a profundidade perfurada vira avanço, porque o fundo dos furos nem sempre rompe por completo, deixando um 'toco' ou sobra de fundo que reduz o ganho líquido. A eficiência típica fica entre 85% e 95%, dependendo da qualidade do plano de fogo (distribuição e inclinação dos furos, tipo e quantidade de carga, sequência de retardos que cria faces livres progressivas), da natureza da rocha e da precisão da perfuração. O avanço por disparo, multiplicado pelo número de ciclos por dia, determina a produtividade da frente e, portanto, o prazo da obra. Há um equilíbrio de engenharia: furos mais profundos dão avanços maiores e menos ciclos, mas perdem precisão e eficiência (desvios de perfuração crescem com o comprimento), além de exigirem mais explosivo por disparo. Otimizar o avanço por disparo — equilibrando comprimento, eficiência e controle de sobre-escavação — é central na engenharia de desmonte. Informe o comprimento perfurado e a eficiência do fogo.
Related Tools
Terzaghi Rock Load Height
Estimate the rock load height over a tunnel crown by Terzaghi's classic method, Hp = Cf·(B + Ht), from the rock load factor Cf (depending on mass quality — ~0 for intact rock to >2 for heavily fractured or swelling rock), the width B and the height Ht of the excavation. Hp represents the loosened rock zone above the tunnel that effectively loads the support — Terzaghi proposed that, due to arching in the mass, only a fraction of the total overburden acts on the lining. This loosening-load model is the historic basis for rock tunnel support design. Multiplying Hp by the unit weight gives the support pressure. Enter the load factor, width and height.
TBM Advance Rate
Calculate a tunnel boring machine's daily advance, advance = PR·U·h, from the instantaneous penetration rate PR (m/h, advance while actively boring), utilization U (0-1, the fraction of time actually boring) and operating hours per day h. The distinction between penetration and utilization is central: penetration depends on geology and cutterhead thrust/torque, but utilization — typically only 30-50% — is limited by ring building, cutter changes, maintenance, muck removal and downtime. Real advance is far below nominal penetration, and improving utilization often pays more than increasing penetration. Enter the penetration rate, utilization and hours per day.
Linear Explosive Charge
Calculate the linear loading density of a blast hole, q = (π/4) × d² × ρ, from the hole diameter d (mm) and the explosive density ρ (g/cm³). The result, in kg of explosive per meter of hole, is how much explosive fits in each meter of charged column — a central parameter of rock blast design. Multiplied by the hole charge height, it gives the charge per hole; combined with the blasted rock volume, it gives the powder factor. Larger diameters and denser explosives raise the linear charge. Enter the hole diameter and the explosive density.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.