Study of presplit blasting under high in-situ stress
When the presplit blasting is applied to rock excavation at a deep level, crack-forming difficulties are encountered due to the characteristics of high geo-stress. In this study, the influences of in-situ stress on rock cracking in presplitting are studied using theoretical and numerical methods.
Pre-Split Techniques: A Review | Agg-Net
Pre-splitting can be defined as 'a technique using lightly charged, closely spaced holes to induce a fracture plane along a required design profile, which isolates …
Introduction to Types of Rock Blasting
Buffer Blasting refers to a designated section of rock between a slope or wall to be formed by line drilling or presplitting during excavation and the production blast. The explosives in the buffer blasthole and the burden in the buffer zone are reduced to prevent damage to the final rock slopes or face. Buffer blasting can be fired after the ...
PRESPLITTING ROCK SLOPES FOR HIGHWAYS
presplitting rock slopes for highways. the presplitting method of producing a plane of split rock along the face of the slope prior to any primary drilling or blasting is described.
FHWA
Presplit blasting, or presplitting, is used before production blasting to protect the final rock face from damage caused by the production blasting. Presplitting creates a fracture plane along the final slope face, which prevents the radial cracks created by production blasting from penetrating into the finished face; without presplitting ...
(PDF) Design and Application of Blasting Parameters for Presplitting
Theoretical calculation and numerical simulation were performed to analyze the mechanism of rock fracturing between holes in deep-hole presplit blasting, crack evolution under the synergistic ...
(PDF) Comparison of Presplit and Smooth Blasting Methods …
To understand differences of smooth and presplit blasting for the excavation of rock wells, two field experiments using these two techniques are implemented at the same test site, respectively.
Numerical investigation of an improved deep-hole presplitting …
The sidewall presplitting blasting effect is not optimal for IV bench sidewall presplitting blasting (Fig. 3). The rock mass at the downstream side is severely fractured with numerous breaks, but the rock mass at the upstream side is unevenly constructed with a slightly undulating upper part, which requires mechanical repair.
Optimization of Drilling Layouts Based on Controlled Presplitting …
Controlled presplitting blasting is a type of non-falling coal (rock) blasting method aimed at improving the level of coal (rock) fissures . As the method can be used to effectively improve the permeability of the coal seam, it is often combined with drilling to pre-drain gas, thus significantly reducing the drilling density and time required ...
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Modeling Explosive/Rock Interaction During Presplitting …
ALEGRA has been applied to a 2-D simulation of presplitting using decoupled explosives in rock blasting with very interesting results. The detonation of the explosive at the bottom of the hole sends a shock wave up the borehole driven by the explosive gas expanding into air.
Study on the technology of enhancing permeability by deep …
The positive effects of deep hole presplitting blasting permeable enhancement technology on the pressure relief and permeability enhancement of a low pressure and high gas coal seam were determined. To reduce gas disasters in low permeability and high gas coal seams and improve gas predrainage efficiency, conventional deep hole presplitting …
Investigation on Rock Fracturing in Presplit Blasting Under …
The evolution characteristics of rock fracturing in presplit blasts are generally affected by in situ stress resulting from tectonic forces in the Earth's crust and from gravity. In this study, rock fracturing under coupled static stress and presplit blasting conditions is comprehensively investigated by combining experimental, theoretical and numerical …
Comparison of Presplit and Smooth Blasting Methods for …
Excavation results of rock wells based on (a) presplit blasting and (b) smooth blasting. To further explore differences of excavation results based on two techniques, the visible …
Effects of in-situ stress on rock cracking in presplit blasting
In rock engineering involving presplit blasting, an individual row of boreholes is arranged at the design boundary and detonated prior to other boreholes in the blasting pattern. During presplitting, the radial cracks from any lightly charged presplit-hole (typically decoupling) either merge adjoining holes or fractures from adjoining presplit ...
Precision Presplitting – Design Aspects
Precision Presplitting is a form of presplitting where the blast design is based on the rock properties and rock mechanics. The differences between normal …
Study on Presplitting Blasting the Roof Strata of Adjacent …
Through presplitting blasting the roadway hard rock layer, the stress propagation path is cut off, and the surrounding rock stress environment of the roadway is improved, to achieve the purpose of controlling the deformation of the roadway caused by stress. Through theoretical analysis, it is determined that the depth of the presplitting ...
Road Cut drilling, presplitting and Blasting
Presplitting is often used to control the highwalls. Millions of pounds of explosives are used every year for this. Dykon Blasting Corp. is a rock blasting contractor and offers drilling and blasting programs for all these highway projects both large and small. Our fleet of high production hydraulic drills makes us capable of the largest most ...
INFLUENCE OF GEOLOGICAL DISCONTINUITIES UPON FRAGMENTATION BY BLASTING
Blasting of a rock mass comprises its interaction with explosive properties, blast geometry and the detonation sequence and/or timings. ... Presplitting is shown to offer little chance of success ...
Precision Rock Excavation: Beyond Controlled Blasting and …
Presplitting is more accurate than smooth blasting, but has the limit of not being conveniently applicable underground (especially in tunneling), where the presence of only one free surface could compromise the result, giving rise to the propagation of unwanted fractures in the rock mass [12,13,14,15].
Applied Research of Deep-hole Presplitting Blasting …
Aiming at the technical problems in deep-hole blasting technology, and the high explosive power at the moment of explosion, but the limited range of fracturing and insufficient rock breaking ...
Effects of in-situ stress on rock cracking in presplit blasting
When the presplit blasting is applied to rock excavation at a deep level, crack-forming difficulties are encountered due to the characteristics of high geo-stress. …
Study on crack propagation of the CO2 presplitting blasting …
CO 2 presplitting blasting is an effective method to increase coal seams permeability and improve gas drainage efficiency. During the blasting process, the empty holes in the coal and rock mass have a significant effect on crack growth. In the experiment, a sample containing empty holes was used for CO 2 presplitting blasting. …
Energies | Free Full-Text | A Case Study of Presplitting Blasting
Advancefixed-distance presplitting blasting (AFPB) technology was proposed to control the caving interval of HMR, and the influence of the controlled interval on the working load of supports was also analyzed. ... Wang, C. Study of millisecond blasting technology of shaft excavation by one-step deep-hole blasting. Rock Soil Mech. 2012, 33, 1742 ...
Out With the Old, in With the New: The Modern Method of Presplitting
The theory of shockwaves in rock blasting has been disproven for over 40 years now, yet many still cling to the idea of shockwave collisions causing a presplit to form. This has many incorrect concepts that make it impossible with a full analysis of the shockwave theory having recently been published (Konya, 2019).
Numerical modeling of presplitting controlled method in continuum rock
Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. The less competent the rock mass itself, the more care has to be taken in avoiding damage. Presplitting is one of the most common methods which is used in many open pit minings and surface blast designs. The …
Precision Rock Excavation: Beyond Controlled Blasting and …
In this paper, the main techniques adopted to control the rock removal process (constituting a real shaping of rock, in the case of sculptures) are reviewed. Presplitting, smooth …
Understanding the connection between blasting and
Explosives are employed throughout the mining industry for primary rock breakage. There are a number of controlled blasting techniques that can be implemented to improve highwall stability. These include line drilling, smooth wall blasting, trim blasting, buffer blasting, air decking, and presplitting.
Rock Blasting and Overbreak Control – Konya Industries
Having worked in and around rock blasting, or having taken other college level courses is a useful background and can help attendees understand some concepts better, but is not required. This course starts from the basics and teaches the practical methods of rock blasting and optimization of a program for better fragmentation, lower vibration ...
Design and Application of Blasting Parameters for Presplitting Hard
Empty holes have been successfully applied to rock presplitting for unloading, blasting excavation of rock drift, and gas extraction from gas-rich coalbeds [6 – 8]. There have been extensive studies on investigating the mechanism of the dynamic behavior for blasting crack propagation as well as the tension crack and guiding role of empty ...