scholarly journals A Preliminary Study on the Design Method for Large-Diameter Deep-Hole Presplit Blasting and Its Vibration-Isolation Effect

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Shuangshuang Xiao ◽  
Hongsheng Wang ◽  
Guowei Dong
Keyword(s):  
Vibration Isolation ◽  
Design Method ◽  
Blast Hole ◽  
Large Diameter ◽  
Field Testing ◽  
Open Pit ◽  
Vibration Velocity ◽  
Deep Hole ◽  
Charge Mass ◽  
Presplit Blasting

Presplit blasting can reduce vibration and back impact induced by cast blasting, thus resulting in a smooth bench slope. To design reasonable presplit blasting parameters, this research investigated the formation of presplit faces based on the explosion mechanics and revealed the cracking mechanism of presplit blasting. According to the stress distribution in the vicinity of the blast holes under the action of explosive stress waves and blasting gas, we deduced theoretical formulae for parameters including charge mass in blast holes, hole spacing, and distance from presplit blast holes to cushion holes. On this basis, a method was proposed for the design of large-diameter deep-hole presplit blasting. Field testing was conducted by setting different spacing for presplit blast holes, to monitor the blasting-induced vibration. The results showed that appropriate hole spacing can reduce the particle vibration velocity and the attenuation index of blasting-induced vibration changed slightly while the attenuation coefficient decreased significantly; the formed presplit faces were smooth and had a high half-cast factor. Finally, the reasonable hole spacing for presplit blasting, distance from presplit blast hole to the cushion hole, and the charge mass in blast holes in the Heidaigou open-pit coal mine were determined, respectively.

Experiment Study on Decreasing Blasting Vibration Adopting Large Diameter Hole-by-Hole Initiation

2011 ◽  
Vol 301-303 ◽  
pp. 1556-1559
Author(s):  
Ren Shu Yang ◽  
Yu Long Che ◽  
Guo Liang Yang ◽  
Chuan Huo
Keyword(s):  
Effective Means ◽  
Large Diameter ◽  
Test Method ◽  
Mine Safety ◽  
Open Pit ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Open Pit Mines ◽  
Diameter Hole ◽  
Vibration Damage

Blasting vibration damage is a major factor in mine safety. Millisecond blasting is an effective means to reduce blasting vibration damage. Taking field test method to study high slope deformation in open pit mines a little bit difference of each quick-fried bore blows up’s blasting vibration damage. Research found that, taking a little bit difference of each quick-fried bore blows up, Slope’s vibration velocity is 0.6cm/s, Compared to initiation by row’s theoretical value reduced by 58.33% , a little bit difference of each quick-fried bore blows up is an effective means to reduce blasting vibration damage, it is great significance for improving the slope stability.

Laboratory and Field Testing of Large-Diameter Plastic Pipe

1997 ◽  
Vol 1594 (1) ◽  
pp. 208-216 ◽  
Author(s):  
P. R. Fleming ◽  
E. Faragher ◽  
C. D. F. Rogers
Keyword(s):  
Laboratory Test ◽  
Design Method ◽  
Large Diameter ◽  
Field Testing ◽  
Theoretical Method ◽  
Test Methods ◽  
Soil System ◽  
The United Kingdom ◽  
Plastic Pipe ◽  
Laboratory Test Results

Flexible plastic pipe is increasingly being used in the United Kingdom for drainage and ducting (conduit) purposes. This increase in use is leading to the introduction of larger-diameter pipes. The U.K. Department of Transport (DoT) uses a recently developed, theoretical method to specify installation conditions in place of traditional techniques (e.g., Spangler’s Iowa method). The DoT design method is outlined. The extensive program of laboratory and field testing carried out at Lough-borough University to determine the performance of plastic pipes under a range of loading conditions that may be expected in practice is then described. Laboratory test results compared well with the results obtained in the field once the different boundary conditions were accounted for, thereby validating the laboratory test methods by suggesting how allowance for field conditions can be made. Some reference is made to the shapes of deformation (determined from circumferential strain data) and the effect of installation conditions upon them. Pipe deformations were found to be well within acceptable, conservative limits under all load regimens, and near equilibrium of the pipe-soil system was established relatively quickly following application of a static or a dynamic load sequence to it.

scholarly journals Design method of blasthole charge structure based on lithology distribution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
YingXian Chen ◽  
Jian Chen ◽  
PengFei Wang ◽  
Meng Zhou ◽  
HongXia Yang ◽  
...  
Keyword(s):  
Design Method ◽  
Blast Hole ◽  
Structure Design ◽  
Open Pit ◽  
Distribution Data ◽  
Geological Exploration ◽  
Charge Structure ◽  
Drilling Rig ◽  
Hard Rocks ◽  
Rock Group

AbstractThe density of geological exploration boreholes is one of the main bases for blasthole charge structure design. Due to the low density of geological exploration boreholes, it is impossible to obtain the blast hole rock formations' distribution accurately. With the development and application of intelligent drilling rigs, the lithology distribution data of the blasthole can be accurately obtained, and a blasthole charge structure design method based on the lithology distribution is proposed. The blasthole lithology data collected by the intelligent drilling rig is divided into 7 categories according to the rock hardness, and the adjacent strata with similar lithology are combined and divided into two groups of soft rocks and hard rocks. According to the rock stratum grouping data of the blasthole and the unit explosive consumption of each type of lithology, the explosive amount and charge length required for the soft rock group and the hard rock group can be calculated, respectively. Finally, the blasthole charge structure is designed according to the thickness and charge position of the hard rocks. With the C++ programming language, this method is realized and applied in the Shengli Open-pit Coal Mine of Inner Mongolia Autonomous Region of China. The application results show that, compared with the traditional hole charging structure design method, this method can realize accurate segmented charging of the hole, improve the blasting effect and the degree of rock fragmentation, and reduce the blasting cost.

scholarly journals Experimental Study on the Blasting Performance of Water-Soil Composite Stemming in Underground Mines

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Xianyang Qiu ◽  
Xiuzhi Shi ◽  
Shu Zhang ◽  
Bo Liu ◽  
Jian Zhou
Keyword(s):  
Fragment Size ◽  
Blast Hole ◽  
Large Diameter ◽  
Underground Mines ◽  
Utilization Rate ◽  
Small Scale ◽  
Deep Hole ◽  
Explosive Energy ◽  
Concrete Masonry ◽  
The Mean

Top stemming is necessary to stop the explosive energy from escaping through the upper part of blast-holes in cutting blasts of large-diameter deep-hole blasting in underground mines. The often-used single soil stemming frequently leads to material clogging which results in reduction of blasting efficiency. In this paper, a new water-soil composite stemming is proposed to solve the problem. A series of small-scale tests were conducted on solid concrete masonry blocks to investigate the effect of top stemming material and stemming length on blasting performance. The experimental results indicated that water stemming was worse at improving the utilization rate of the explosion energy compared with single soil stemming of the same length. Further, the mean fragment size decreased with the increase of stemming length for single water stemming. Three schemes of water-soil composite stemming were designed and the scheme with soil in the lower part and water filled in bags in the higher part had the best fragmentation. The water-soil composite stemming was applied in underground stopes, and field results indicated that the newly proposed stemming led to similar rock fragmentation with traditional single soil stemming, but greatly reduced the clogged blast hole ratio, thus effectively improving blasting and mining efficiency.

Analysis of Efficiency of Drilling of Large-Diameter Wells With a Profiled Wing Bit / Badania Efektywności Wiercenia Studni Wielkośrednicowych Świdrem Skrawającym z Profilowanymi Skrzydłami

2012 ◽  
Vol 57 (2) ◽  
pp. 363-373
Author(s):  
Jan Macuda
Keyword(s):  
Average Rate ◽  
Large Diameter ◽  
Open Pit ◽  
Mechanical Parameters ◽  
Drilling Rate ◽  
Geological Conditions ◽  
Rock Drillability ◽  
Drilling Technology ◽  
Weight On Bit ◽  
Rotary Speed

Abstract In Poland all lignite mines are dewatered with the use of large-diameter wells. Drilling of such wells is inefficient owing to the presence of loose Quaternary and Tertiary material and considerable dewatering of rock mass within the open pit area. Difficult geological conditions significantly elongate the time in which large-diameter dewatering wells are drilled, and various drilling complications and break-downs related to the caving may occur. Obtaining higher drilling rates in large-diameter wells can be achieved only when new cutter bits designs are worked out and rock drillability tests performed for optimum mechanical parameters of drilling technology. Those tests were performed for a bit ø 1.16 m in separated macroscopically homogeneous layers of similar drillability. Depending on the designed thickness of the drilled layer, there were determined measurement sections from 0.2 to 1.0 m long, and each of the sections was drilled at constant rotary speed and weight on bit values. Prior to drillability tests, accounting for the technical characteristic of the rig and strength of the string and the cutter bit, there were established limitations for mechanical parameters of drilling technology: P ∈ (Pmin; Pmax) n ∈ (nmin; nmax) where: Pmin; Pmax - lowest and highest values of weight on bit, nmin; nmax - lowest and highest values of rotary speed of bit, For finding the dependence of the rate of penetration on weight on bit and rotary speed of bit various regression models have been analyzed. The most satisfactory results were obtained for the exponential model illustrating the influence of weight on bit and rotary speed of bit on drilling rate. The regression coefficients and statistical parameters prove the good fit of the model to measurement data, presented in tables 4-6. The average drilling rate for a cutter bit with profiled wings has been described with the form: Vśr= Z ·Pa· nb where: Vśr- average drilling rate, Z - drillability coefficient, P - weight on bit, n - rotary speed of bit, a - coefficient of influence of weight on bit on drilling rate, b - coefficient of influence of rotary speed of bit on drilling rate. Industrial tests were performed for assessing the efficiency of drilling of large-diameter wells with a cutter bit having profiled wings ø 1.16 m according to elaborated model of average rate of drilling. The obtained values of average rate of drilling during industrial tests ranged from 8.33×10-4 to 1.94×10-3 m/s and were higher than the ones obtained so far, i.e. from 181.21 to 262.11%.

Prediction of the Ground Vibration Rate during Large-scale Explosions in the Underground Conditions

2021 ◽  
pp. 41-45
Author(s):  
V.N. Tyupin ◽  
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Underground Mining ◽  
Calculated Data ◽  
Ground Vibration ◽  
Open Pit ◽  
Vibration Velocity ◽  
Earth Surface ◽  
Seismic Safety ◽  
The Earth

At present, to ensure seismic safety in massive explosions, the analytical dependence of the determination of the vibration velocity of M.A. Sadovsky rock mass is mainly used. This dependence is widely used in the creation of seismic-safe technologies for mineral deposits open-pit and underground mining. However, scientific research and production experience showed that the rate of oscillation depends on the energy parameters of the explosive, the diameter and length of its charges, the number of simultaneously exploded charges, the number of deceleration stages, the deceleration interval, etc. The purpose of this article is to predict the speed fluctuations of the massif on the earth surface when conducting the underground explosions depending on the parameters of large-scale explosions and physical-technical properties of the rock masses in the areas of explosion of the protected object. The formulas for calculating the velocity of rock mass on the earth surface during large-scale explosions in the underground conditions are substantiated and presented. The formulas were used for calculating the vibration velocities of the rock mass on the earth surface in accordance with the parameters of drilling and blasting operations during large-scale explosions in the mines of GK VostGOK. Comparison of theoretical (calculated) data and the results of actual measurements indicates their convergence. By changing the controlled parameters in the calculation formulas, it is possible to quantitatively reduce the seismic effect of a large-scale explosions on the protected objects. Further research will be aimed at studying the influence of tectonic faults, artificial contour crevices, filling massif or mined-out space on the rate of seismic-explosive vibrations during blasting operations in the mines. The research results can be used in the preparation of rules for conducting large-scale explosions at the underground mining.

Matching Design of Active Magnetic Bearing and Elastic Support Vibration Isolator

2020 ◽  
Author(s):  
Yichen Yao ◽  
Yixin Su ◽  
Tianye Yu ◽  
Gexue Ren ◽  
Suyuan Yu
Keyword(s):  
Frequency Domain ◽  
Vibration Isolation ◽  
Design Method ◽  
Rotating Machinery ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Vibration Isolators ◽  
Active Vibration ◽  
Matching Relation ◽  
Active Vibration Isolation

Abstract In modern industries, high-speed machinery occupies a fundamental place. However, rotating machinery will inevitably produce a variety of structural noise and vibration. Generally, vibration isolation means can be divided into active vibration isolation and passive vibration isolation, among which the most representative are active magnetic bearings (AMBs) and vibration isolators, respectively. The combination of active magnetic bearings and vibration isolators is widely used in rotating machinery because of its excellent effect in vibration and noise reduction. This paper concentrates on the analysis of the vibration transmission mechanism of the active magnetic bearings coupled with the vibration isolators. A 30 kW prototype pump is taken as an example to help describe the research method. The model of the pump is first established. The stationary pump components and the rotor are respectively modeled through the finite element method and converted to substructure modal expression after low-order modal extraction. The bearing force is simplified to spring-dampers with equivalent stiffness and equivalent damping relating to the exciting frequency. The vibration isolators are simplified as three-dimensional spring-dampers. Based on the model, this paper then investigates the matching relation of the AMBs and the vibration isolators and proposes a dynamic vibration isolation design method for the rotor-AMBs-flexible support system. On the basis of the frequency-domain response of the original design, this design method gives the frequency-domain curves of the desired stiffness and damping of the suitable active vibration isolation, which can be used to guide the controller design of the AMBs and isolators selection. According to the design, we have done laboratory experiments on the prototype pump. The results show that the design method based on matching relation has good performance in vibration isolation.

A Reinforcement Design Method Based on Analysis of Large Openings in Cylindrical Pressure Vessels

1996 ◽  
Vol 118 (4) ◽  
pp. 502-506 ◽  
Author(s):  
M. D. Xue ◽  
K. C. Hwang ◽  
W. Lu¨ ◽  
W. Chen
Keyword(s):  
Fourier Series ◽  
Present Method ◽  
Fourier Coefficients ◽  
Design Method ◽  
Large Diameter ◽  
Pressure Vessels ◽  
Diameter Ratio ◽  
Cylindrical Coordinates ◽  
Reinforcement Design ◽  
Good Agreement

The analytical solution is given for two orthogonally intersecting cylindrical shells with large diameter ratio d/D subjected to internal pressure. The modified Morley equation is used for the shell with cutout and the Love equation for the tube with nonplanar end. The continuity conditions of forces and displacements at the intersection are expressed in 3-D cylindrical coordinates (ρ, θ, z), and are expanded in Fourier series of θ. The Fourier coefficients are obtained by numerical quadrature. The present results are in good agreement with those obtained by tests and by FEM for ρ0 = d/D ≤ 0.8. The typical curves of SCF versus t/T and d/DT and reinforcement coefficients g, h versus D/T0 for each ρ0 are given on the present method.

Investigation on Deep Hole Trepanning of TC10 Titanium Alloy

2019 ◽  
Author(s):  
Xiaolan Han ◽  
Zhanfeng Liu
Keyword(s):  
Titanium Alloy ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Process Parameters ◽  
Thrust Force ◽  
Large Diameter ◽  
Manufacturing Cost ◽  
Deep Hole ◽  
Technical Problems ◽  
Material Utilization

Abstract Titanium alloy is a typical hard-to-machine material, and has a relatively expensive material price. For deep-hole tubes made of titanium alloys, the material utilization rate of direct deep-hole drilling is relatively low, especially for large diameter holes. Deep-hole trepanning provides an effective method that reduces manufacturing cost and improves the material utilization which is used on larger diameter bars. In this paper, deep-hole trepanning tests are carried out on the TC10 titanium alloys to resolve the key technical problems. The thrust force and torque, tool wear, and chip morphology are analyzed based on the different process parameters. The results show that appropriate process parameters can remove the chips easily and reduce the thrust force and tool wear. The titanium alloy deep-hole trepanning has a good drilling effect and solves the problem of drilling deep, large diameter holes in titanium alloy tubes, which has practical significance for reducing production cost and improving material utilization.

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