scholarly journals Study of Two-Step Parallel Cutting Technology for Deep-Hole Blasting in Shaft Excavation

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Renshu Yang ◽  
Changda Zheng ◽  
Liyun Yang ◽  
Jinjing Zuo ◽  
Tonglei Cheng ◽  
...  
Keyword(s):  
Free Surface ◽  
Theoretical Analysis ◽  
Hard Rock ◽  
Charge Ratio ◽  
Utilization Rate ◽  
Specific Charge ◽  
Deep Hole ◽  
Lower Section ◽  
Engineering Applications ◽  
Blasting Excavation

In hard rock deep-hole blasting excavation, blastholes are rarely utilized due to the clamping effect of the lower rock, which affects excavation progress and restricts the development and application of deep-hole blasting technology. Cut blasting is a key to improving excavation speed. In this paper, a new cutting method designating the two-step cutting technology was presented. The blasthole was divided into upper and lower sections without changing the blasthole layout. The upper section was detonated first, creating sufficient free surface for the lower section, which was detonated secondly. This created a larger cavity and improved blasthole utilization. Results showed good blasting effects for two-step cutting technology through theoretical analysis and engineering applications. The blasthole utilization rate was 96.1% when the upper and lower specific charge ratio = 0.78. This paper provides a good reference for resolving the low blasthole utilization problem in deep-hole blasting of vertical shafts within a hard rock.

scholarly journals Key Blasting Parameters for Deep-Hole Excavation in an Underground Tunnel of Phosphorite Mine

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Xiu-wei Chai ◽  
Sha-sha Shi ◽  
Yao-feng Yan ◽  
Jian-guo Li ◽  
Long Zhang
Keyword(s):  
Free Surface ◽  
Production Capacity ◽  
Energy Utilization ◽  
Underground Mines ◽  
Hole Drilling ◽  
Utilization Rate ◽  
Deep Hole ◽  
Comparison Results ◽  
Tunnel Blasting ◽  
Interaction Modeling

Ever increasing mine production capacity and mechanized operations enable advanced drilling equipment to be widely adopted in underground mines. In order to achieve satisfactory blasting performance in tunnel advance, there is a critical need to optimize the blasting technique to match the large deep-hole drilling capability. In this study, through theoretical analysis of tunnel blasting, the layout of cutting holes was found to be the key factor controlling the blasting performance. The deep-hole cutting effect was first investigated by analyzing the influence of the free surface of a hollow hole using the fluid-structure interaction modeling method in ANSYS/LS-DYNA. Then the rock dynamic evolution processes of blasting using a double-cavity grooving and a four-cavity grooving were compared and analyzed towards an understanding of the influence of the spacing and layout of cutting holes on the blasting performance. The comparison results show that four empty hole cut layouts yield larger effective free surface than that of the two empty hole cut layouts. This is because larger compensation space for breaking of rock and expansion of gas is more conducive to improving the energy utilization rate of explosives and thus improving the blasting performance and the footage of cyclic blasting. The results indicated that the blasting performance can be improved by reserving reasonable compensation space in the grooving area.

An MLSPH algorithm for free surface flows in engineering applications

2003 ◽  
pp. 873-876
Author(s):  
L. Cueto-Felgueroso ◽  
I. Colominas ◽  
G. Mosqueira ◽  
F. Navarrina ◽  
M. Casteleiro
Keyword(s):  
Free Surface ◽  
Free Surface Flows ◽  
Engineering Applications ◽  
Surface Flows

Study on Methods of Exploring the Loosening Radius of Deep-Hole Controlling Blasting

2013 ◽  
Vol 734-737 ◽  
pp. 650-655
Author(s):  
Wen Qing Zhang ◽  
Jian Liu
Keyword(s):  
Theoretical Analysis ◽  
Coal Seam ◽  
Gas Flow ◽  
Critical Factor ◽  
Field Investigation ◽  
Flow Index ◽  
Low Permeability ◽  
Deep Hole ◽  
Deep Borehole ◽  
Outburst Coal Seam

Deep borehole controlling blasting is one of the most popular methods which used to improve permeability of low permeability and highly gassy coal seam. Proper interval between blasting hole is the critical factor. On this paper, the theory and insufficiency of each method are discussed by theoretical analysis and field investigation. The result shows that, because of the complexity of outburst coal seam, the measuring result got by different methods is relative and declinational. We need to make a right choice according to the actual demand. And the method of gas flow index is quickly, visual and reliable, which to be worth paying the utmost attention to.

Analysis of pipe flow with free surface. Part II. Theoretical analysis and experiment

1994 ◽  
Vol 13 (5) ◽  
pp. 249-260
Author(s):  
Amane Tanaka ◽  
Ryuji Takaki
Keyword(s):  
Free Surface ◽  
Theoretical Analysis ◽  
Pipe Flow ◽  
Surface Part

A theoretical analysis of free-surface flows of saturated granular–liquid mixtures

2008 ◽  
Vol 608 ◽  
pp. 393-410 ◽  
Author(s):  
D. BERZI ◽  
J. T. JENKINS
Keyword(s):  
Free Surface ◽  
Theoretical Analysis ◽  
Eddy Viscosity ◽  
Numerical Solutions ◽  
Liquid Mixtures ◽  
Free Surface Flows ◽  
Two Phase ◽  
Surface Flows ◽  
Physical Experiments ◽  
Analytical Expressions

A simple two-phase model for steady fully developed flows of particles and water over erodible inclined beds is developed for situations in which the water and particles have the same depth. The rheology of the particles is based on recent numerical simulations and physical experiments, the rheology of the fluid is based on an eddy viscosity, and the interaction between the particles and the fluid is through drag and buoyancy. Numerical solutions of the resulting differential equations and boundary conditions provide velocity profiles of the fluid and particles, the concentration profile of the particles, and the depth of the flow at a given angle of inclination of the bed. Simple approximations permit analytical expressions for the flow velocities and the depth of flow to be obtained that agree with the numerical solutions and those measured in experiments.

Study on Parameters of Deep-Hole Loose Blasting under the Condition of High Stress

2014 ◽  
Vol 644-650 ◽  
pp. 646-649
Author(s):  
Zhi Tao Zheng ◽  
Ying Xu
Keyword(s):  
Theoretical Analysis ◽  
Coal Mine ◽  
High Stress ◽  
Calculation Formula ◽  
Rock Blasting ◽  
Deep Hole ◽  
Design Work ◽  
Hole Wall ◽  
Deep Rock ◽  
Reference Design

The hole wall crushed and fractured zones length has been derived theoretically,and put forward the calculation formula of blasting crushing circle and radius of the corresponding fracture zone.Corresponding to the deep rock blasting parameters design on the basis of theoretical analysis,then lead to the reasonable parameters.These can provide certain reference design work for coal mine deep rock blasting parameters.

scholarly journals Experimental Study of Gangue Layer Weakening with Deep-Hole Presplitting Blasting

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jianchi Hao ◽  
Lifeng Ren ◽  
Hu Wen ◽  
Duo Zhang
Keyword(s):  
Experimental Study ◽  
Coal Seam ◽  
Coal Mining ◽  
Hard Rock ◽  
Blast Hole ◽  
Normal Operation ◽  
Deep Hole ◽  
Coal Seams ◽  
Layer 4 ◽  
Similar Simulation

Advances in coal mining technology and an increase in coal output are resulting in increasingly challenging conditions being encountered at coal seams. This is particularly so at thin coal seams, where a large number of hard rock layers known as gangue are often present, which seriously affect the normal operation of the shearer and reduce coal output. Therefore, the effective weakening of hard gangue layers in a coal seam is crucial to ensure that the shearer operates effectively and that coal output is maximized. In this paper, the weakening effect of deep-hole presplitting blasting technology on the hard gangue layer in a coal seam is studied via a similar simulation. Four test schemes are designed: (1) A blasting hole spacing of 200 mm with the holes offset vertically. (2) A blast hole spacing of 300 mm with the holes offset vertically. (3) A blast hole spacing of 200 mm with the holes parallel to the gangue layer. (4) A blasting hole spacing of 200 mm with the holes offset vertically and initiation of interval blasting. The effect of the different blasting hole spacings and arrangements and different detonation methods on the weakening of coal seam clamping by gangue is studied, and the best configuration is identified. This improves the effect of weakening the coal gangue layer by deep-hole presplitting blasting.

The Flat Solitary Waves Due to a Submerged Moving Body in a Two-Layer Fluid With a Free Surface

2005 ◽  
Author(s):  
Gang Wei ◽  
Xiao-Bing Su ◽  
Yun-Xiang You
Keyword(s):  
Free Surface ◽  
Theoretical Analysis ◽  
Solitary Wave ◽  
Solitary Waves ◽  
Experimental Results ◽  
Stable System ◽  
Weakly Nonlinear ◽  
Submerged Body ◽  
Moving Body

The flat solitary wave with the behavior of conjugate flow, generated by a submerged body moving in a two-layer fluid, is investigated. A criteria about the existence of weakly nonlinear weakly dispersive flat solitary wave is given. The condition of the stable system of conjugate flow is obtained. The solution of the flat solitary wave satisfying the criteria is numerically verified to be unique. Theoretical analysis is qualitatively consistent with the experimental results obtained by the authors.

scholarly journals Blast-Casting Mechanism and Parameter Optimization of a Benched Deep-Hole in an Opencast Coal Mine

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Li Ma ◽  
Xingping Lai ◽  
Jianguo Zhang ◽  
Shuangshuang Xiao ◽  
Leiming Zhang ◽  
...  
Keyword(s):  
Factor Analysis ◽  
Casting Process ◽  
Rock Properties ◽  
Specific Charge ◽  
Deep Hole ◽  
Analysis Method ◽  
Analysis Model ◽  
Factors Influencing ◽  
Powder Factor ◽  
Minimum Resistance

During the research on bench deep-hole blast casting, the blast-casting parameters are directly related to the blast-casting results, so it could reveal the mechanism for improving the effect thereof. Based on the principle of the plane charge method, both the stress wave and detonation gas were considered to affect rock fragmentation and casting, a model of overburden fragmentation and casting process around the blasting hole was established, and bench deep-hole blast-casting behaviours were elucidated. By using the Factor Analysis Method (FAM), a correlation analysis model of factors influencing blast-casting results was built. The results proved that powder factor (or specific charge) ranked first in terms of its influence, followed by hole spacing, minimum resistance line, burden, and bench height. The formulae for calculating the limit powder factor value and the spacing of blasting holes were derived for different rock properties. The results showed that the optimum hole spacing was no more than 12.49 m and the powder factor was no more than 0.75 kg/m3, and it proved that an effective casting percentage (ECP) of 34% could be realized.

Sign in / Sign up

Export Citation Format

Share Document