Ineffective Rock Breaking and its Impacts on Pick Failures

2014 ◽  
Author(s):  
Y. Sun ◽  
X.S. Li
Keyword(s):  
Rock Breaking

Rock Breaking Model Under Dynamic Load with the Application of Torsional and Axial Percussion Hammer

2016 ◽  
Author(s):  
Zichen Xu ◽  
Yan Jin ◽  
Bing Hou ◽  
Jingnan Don ◽  
Huiwen Pang ◽  
...  
Keyword(s):  
Dynamic Load ◽  
Rock Breaking

scholarly journals Prediction of shallow bit position based on vibration signal monitoring of bit broken rock

2021 ◽  
Vol 17 (1) ◽  
pp. 155014772199170
Author(s):  
Jinping Yu ◽  
Deyong Zou
Keyword(s):  
Acoustic Emission ◽  
Time Domain ◽  
Vibration Signal ◽  
Rock Breaking ◽  
Drill String ◽  
Mean Square ◽  
Drilling Force ◽  
Emission Signal ◽  
Force Signal ◽  
The Mean

The speed of drilling has a great relationship with the rock breaking efficiency of the bit. Based on the above background, the purpose of this article is to predict the position of shallow bit based on the vibration signal monitoring of bit broken rock. In this article, first, the mechanical research of drill string is carried out; the basic changes of the main mechanical parameters such as the axial force, torque, and bending moment of drill string are clarified; and the dynamic equilibrium equation theory of drill string system is analyzed. According to the similarity criterion, the corresponding relationship between drilling process parameters and laboratory test conditions is determined. Then, the position monitoring test system of the vibration bit is established. The acoustic emission signal and the drilling force signal of the different positions of the bit in the process of vibration rock breaking are collected synchronously by the acoustic emission sensor and the piezoelectric force sensor. Then, the denoised acoustic emission signal and drilling force signal are analyzed and processed. The mean value, variance, and mean square value of the signal are calculated in the time domain. The power spectrum of the signal is analyzed in the frequency domain. The signal is decomposed by wavelet in the time and frequency domains, and the wavelet energy coefficients of each frequency band are extracted. Through the wavelet energy coefficient calculated by the model, combined with the mean, variance, and mean square error of time-domain signal, the position of shallow buried bit can be analyzed and predicted. Finally, by fitting the results of indoor experiment and simulation experiment, it can be seen that the stress–strain curve of rock failure is basically the same, and the error is about 3.5%, which verifies the accuracy of the model.

scholarly journals Numerical simulation of the laws of fracture propagation of multi-hole linear co-directional hydraulic fracturing

2021 ◽  
pp. 014459872198899
Author(s):  
Weiyong Lu ◽  
Changchun He
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Minimum Principle ◽  
Fracture Propagation ◽  
Axial Direction ◽  
Rock Breaking ◽  
Hydraulic Fractures ◽  
Directional Hydraulic Fracturing ◽  
Fracture Intersection ◽  
Expansion Stage

Directional rupture is one of the most important and most common problems related to rock breaking. The goal of directional rock breaking can be effectively achieved via multi-hole linear co-directional hydraulic fracturing. In this paper, the XSite software was utilized to verify the experimental results of multi-hole linear co-directional hydraulic fracturing., and its basic law is studied. The results indicate that the process of multi-hole linear co-directional hydraulic fracturing can be divided into four stages: water injection boost, hydraulic fracture initiation, and the unstable and stable propagation of hydraulic fracture. The stable expansion stage lasts longer and produces more microcracks than the unstable expansion stage. Due to the existence of the borehole-sealing device, the three-dimensional hydraulic fracture first initiates and expands along the axial direction in the bare borehole section, then extends along the axial direction in the non-bare hole section and finally expands along the axial direction in the rock mass without the borehole. The network formed by hydraulic fracture in rock is not a pure plane, but rather a curved spatial surface. The curved spatial surface passes through both the centre of the borehole and the axial direction relative to the borehole. Due to the boundary effect, the curved spatial surface goes toward the plane in which the maximum principal stress occurs. The local ground stress field is changed due to the initiation and propagation of hydraulic fractures. The propagation direction of the fractures between the fracturing boreholes will be deflected. A fracture propagation pressure that is greater than the minimum principle stress and a tension field that is induced in the leading edge of the fracture end, will aid to fracture intersection; as a result, the possibility of connecting the boreholes will increase.

The Technical Development for Increasing ROP with Particle Impact Drilling in China

2014 ◽  
Vol 904 ◽  
pp. 292-295 ◽  
Author(s):  
Jian Zhao ◽  
Yi Ji Xu
Keyword(s):  
Field Test ◽  
Hard Rock ◽  
Rock Breaking ◽  
Particle Impact ◽  
Sound Effect ◽  
Deep Well ◽  
Working Principle ◽  
Hard Formation ◽  
Field Test Result ◽  
Test Result

Field test of particle impact drilling (PID) technology was firstly carried out in deep well and hard formation in Sichuan province china on Oct. 2013. The test formation was named Xu Jiahe, which was very difficult to penetration. Field test result shows that the ROP (rate of penetration) was nearly doubled by this technology. It indicates that there is a profound application prospect of particle impact drilling, especially for hard rock formation. In this paper, the equipment and working principle was analyzed. The experiment and simulation results showed that the rock breaking efficiency was highly increased by this technology. The details of this field test were presented too in this paper that proved the sound effect of PID.

High-Efficiency Cut Blasting with Shell Radial Shaped Charge in Laboratory-Scale Blasting

2015 ◽  
Vol 1094 ◽  
pp. 445-450 ◽  
Author(s):  
Wei Chen ◽  
Hong Hao Ma ◽  
Zhao Wu Shen ◽  
De Bao Wang
Keyword(s):  
High Efficiency ◽  
Circular Tube ◽  
Rock Breaking ◽  
Shaped Charge ◽  
Axial Line ◽  
Rock Excavation ◽  
Crack Network ◽  
Utilization Ratio ◽  
The Cost ◽  
The Ideal

Due to the inefficiency problem of the cut blasting in rock excavation and rock breaking, a shell radial shaped charge device was proposed based of the ideal of ‘cutting to slotting’ and it was validated through experiments. For this device, the shell materials are used to be shaped materials and multiple shaped ring is designed on the circular tube. It can not only reduce charge quantity but also raise the utilization ratio of explosive energy. After explosion, multiple radial shaped charge jets can be formed along the axial line in sequence and then the surrounding rock mass would be cracked. The crack network will be formed along with the further extension of the fraction under the action of quasi static loading of detonation gas. The shell radial shaped charge device was tested through the cut blasting model experiment. Experimental results show that the utilization ratio of blasting hole nearly approaches 98% with this device. The blasting efficiency and cyclical footage can be improved effectively and the cost of drifting can also be reduced.

Rock Breaking Model Under Dynamic Load with the Application of Torsional and Axial Percussion Hammer

2016 ◽  
Author(s):  
Zichen Xu ◽  
Yan Jin ◽  
Bing Hou ◽  
Jingnan Don ◽  
Huiwen Pang ◽  
...  
Keyword(s):  
Dynamic Load ◽  
Rock Breaking

Fractal Characteristics of Sandstone Cutting Fracture under Mechanical Shock Loading Conditions

2012 ◽  
Vol 226-228 ◽  
pp. 1789-1794 ◽  
Author(s):  
Shu Ren Wang ◽  
Paul Hagan ◽  
Yan Cheng
Keyword(s):  
Fractal Dimension ◽  
Size Distribution ◽  
Structural Integrity ◽  
Theoretical Calculations ◽  
Mesh Size ◽  
Rock Cutting ◽  
Weight Percent ◽  
Rock Breaking ◽  
Engineering Practice ◽  
Mechanical Shock

It is the key to guide rock-breaking design and engineering practice for how to obtain a reasonable test indicator to assess the cuttability of the rock. Some sandstone samples were tested by using the linear rock cutting machine in the school of mining engineering, University of New South Wales (UNSW), Australia. The curves characteristics for the weight percent of the broken debris with the mesh size distribution were obtained through the screening statistics. Furthermore, the fractal dimension of the specimen broken debris was derived through theoretical calculations and statistical analysis. The results showed that the rock cutting fragmentation is of significant fractal features under the mechanical shock loads. The broken debris fractal dimension of the structural integrity specimens is bigger, the range of the fractal dimension is smaller and the broken debris size distribution is more even than that of the poor structural integrity specimens. The fractal dimension is the ideal test indicator to assess and analysis the rock-breaking degree.

scholarly journals The effects of process parameters on the rock-breaking efficiency of multi-nozzle jet

2021 ◽  
pp. 108857
Author(s):  
Lipeng He ◽  
Yanbao Liu ◽  
Yanqing Wu ◽  
Haitao Sun ◽  
Kai Shen ◽  
...  
Keyword(s):  
Process Parameters ◽  
Rock Breaking
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