scholarly journals Study on Pressure Relief Effect of Rock Mass with Different Borehole Parameters

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Chao Peng ◽  
Wanrong Liu
Keyword(s):  
Acoustic Emission ◽  
Rock Mass ◽  
Rock Burst ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Reduction Degree ◽  
Occurrence Time ◽  
Pressure Relief ◽  
Research Results ◽  
Relief Effect

Rock burst is one of the disaster accidents that can easily happen in rock cavern engineering. At present, one of the most commonly used methods to control rock burst is borehole pressure relief technology. In this paper, the influence of drilling layout schemes on the pressure relief effect of surrounding rock mass is systematically studied. The research results show that the strength reduction degree, AE evolution characteristics, failure modes of rock samples with different borehole positions, boreholes spacing, boreholes dip angles, and boreholes layout forms are different. The strength reduction degree of rock sample with an inclined arrangement form is the largest, followed by the arrangement form being up three-flower layout or down three-flower layout. Using the inclined layout and three-flower layout can achieve better pressure relief effect of the surrounding rock mass. The research results are beneficial to the rock burst of surrounding rock of the cavern. The acoustic emission can effectively monitor the stability of the surrounding rock of the cavern. However, the threshold value and the occurrence time of the acoustic emission of the cavern instability changed after the cavern surrounding rock is drilled holes. If the borehole is arranged at the surrounding rock mass, the occurrence time of the cavern instability may be advanced.

Numerical Experiments of Drilling Pressure Relief Preventing Roadway Rock Burst

2013 ◽  
Vol 353-356 ◽  
pp. 1583-1587 ◽  
Author(s):  
Yan Liang Wen ◽  
Guo Jian Zhang ◽  
Zhi Qiang Zhang
Keyword(s):  
Rock Mass ◽  
Rock Burst ◽  
High Stress ◽  
Simulation Software ◽  
Control Technique ◽  
Pressure Relief ◽  
Main Factors ◽  
Rock Burst Mechanism ◽  
Research Situation ◽  
Relief Effect

Based on rock burst mechanism and the present research situation of control technique, pressure relief process of drilling to rock burst roadway is modeled by numerical simulation software, the contrast and analysis of stress field of surrounding rock are put up with and without pressure relief. The results of the calculation indicate that after drilling high stress area on the both sides of the roadway reduces obviously, but stress peak increases and its position is not converted into the deep areas evidently. It is the energy of the high stress area that makes the rock mass between the drillings failure, which achieves the purpose of pressure relief. Drilling diameter and space between drillings are main factors influencing pressure relief effect. The major the drilling diameter and the smaller the space between boreholes, the more complete the rock mass between the drillings failure and the better the pressure relief effect.

scholarly journals Stability Control of Deep Coal Roadway under the Pressure Relief Effect of Adjacent Roadway with Large Deformation: A Case Study

2021 ◽  
Vol 13 (8) ◽  
pp. 4412
Author(s):  
Houqiang Yang ◽  
Nong Zhang ◽  
Changliang Han ◽  
Changlun Sun ◽  
Guanghui Song ◽  
...  
Keyword(s):  
Large Deformation ◽  
Coal Mine ◽  
High Stress ◽  
Surrounding Rock ◽  
Western China ◽  
Engineering Practice ◽  
Pressure Relief ◽  
Coal Roadway ◽  
And Control ◽  
Relief Effect

High-efficiency maintenance and control of the deep coal roadway surrounding rock stability is a reliable guarantee for sustainable development of a coal mine. However, it is difficult to control the stability of a roadway that locates near a roadway with large deformation. With return air roadway 21201 (RAR 21201) in Hulusu coal mine as the research background, in situ investigation, theoretical analysis, numerical simulation, and engineering practice were carried out to study pressure relief effect on the surrounding rock after the severe deformation of the roadway. Besides, the feasibility of excavating a new roadway near this damaged one by means of pressure relief effect is also discussed. Results showed that after the strong mining roadway suffered huge loose deformation, the space inside shrank so violently that surrounding rock released high stress to a large extent, which formed certain pressure relief effect on the rock. Through excavating a new roadway near this deformed one, the new roadway could obtain a relative low stress environment with the help of the pressure relief effect, which is beneficial for maintenance and control of itself. Equal row spacing double-bearing ring support technology is proposed and carried out. Engineering practice indicates that the new excavated roadway escaped from possible separation fracture in the roof anchoring range, and the surrounding rock deformation of the new roadway is well controlled, which verifies the pressure relief effect mentioned. This paper provides a reference for scientific mining under the condition of deep buried and high stress mining in western China.

The Research on Application of Strength Reduction Finite Element Method in Stability Analysis of Weak Intercalated Rock Tunnel

2011 ◽  
Vol 255-260 ◽  
pp. 1926-1929
Author(s):  
Da Kun Shi ◽  
Yang Song Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rock Mass ◽  
Safety Factor ◽  
Slip Surface ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Stability Of Surrounding Rock ◽  
The Stability ◽  
Element Method

Based on geologic condition of one tunnel surrounding rock mass, systematic numerical tests had been carried out to study the stability of surrounding rock mass with different distributions of weak intercalated rock by the FEM software ABAQUS and strength reduction finite element method. Some quantificational results about the stability of surrounding rock mass were summarized. And the safety factor and latent slip surface were worked out. The stability of surrounding rock mass was judged by strength reduction finite element method. According to the analysis above, it’s known that the discrepancy of two rules is small; the safety factor is the lowest when weak intercalated rock in vault, and when at bottom, it’s higher than that of in vault. The conclusion can be used to guide the procedure of construction and ensure the safety.

scholarly journals Preliminary Discussion on Comprehensive Research Method for Rock Burst in Coal Mine Based on Newton’s Second Law

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Jianping Zuo ◽  
Hongqiang Song ◽  
Yunqian Jiang ◽  
Shankun Zhao ◽  
Meilu Yu ◽  
...  
Keyword(s):  
Rock Mass ◽  
Rock Burst ◽  
Research Method ◽  
Surrounding Rock ◽  
Research Progress ◽  
Field Energy ◽  
Second Law ◽  
Preliminary Discussion ◽  
Geological Conditions ◽  
Newton's Second Law

Rock burst is one of the major dynamic disasters that directly threaten production safety in coal mines. According to the current research, the occurrence of rock burst can be described by the generalized Newton’s second law with three elements which are research object, force condition, and motion state. These three elements refer to the coal and rock mass in the mining area, concentrated static and dynamic loads, and dynamic instability of surrounding rock, respectively. On this basis, a comprehensive rock burst research method involving the three elements of Newton’s second law was proposed, which especially focuses on the investigation into geological conditions of mining areas. The research procedure of this method specifically includes the detailed exploration of engineering geological bodies, the classification and stability evaluation of surrounding rock, the measurement and inversion of in situ stress, the evolution analysis of mining-induced stress field, energy field, and fracture field, the study of multiscale failure mechanism of coal and rock mass, the establishment of theoretical failure model of coal and rock mass, the real-time monitoring and warning in potentially dangerous areas, and the reasonable prevention and control in key risk zones. As a preliminary discussion, the significant research progress in each aspect mentioned above has been reviewed and the feasible research directions of rock burst are presented in this paper.

scholarly journals Study on Pressure Relief Effect and Rock Failure Characteristics with Different Borehole Diameters

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shiwei Liang ◽  
Long Zhang ◽  
Di Ge ◽  
Qiong Wang
Keyword(s):  
Acoustic Emission ◽  
Research Result ◽  
Borehole Diameter ◽  
Tunnel Construction ◽  
Emission Characteristics ◽  
Pressure Relief ◽  
Failure Characteristics ◽  
Damage And Failure ◽  
Acoustic Emission Count ◽  
Relief Effect

Rock burst is a common tunnel and mine dynamic disaster, especially for deep buried tunnels, which often leads to tunnel construction delay and even induces tunnel collapse and subsidence of strata. Rock drilling is one of the effective pressure relief methods to prevent these disasters. In order to study the influence of borehole diameter on rock mass pressure relief effect, indoor acoustic emission characteristics and numerical simulation of rock samples with different borehole diameter were studied. The research result shows that with the increase in borehole diameter, the effect of borehole pressure relief is better. Different borehole diameters do not change the overall trend of acoustic emission evolution, but it will lead to different acoustic emission count characteristics of rock damage and failure, especially the maximum acoustic emission count characteristics and corresponding strain values. The existence of drilling will lead to the failure stress of rock in advance. Moreover, the existence of drilling causes a great change in the failure mode of the specimen.

scholarly journals Stress Relief and Support for Stability of Deep Mining Roadway with Thick Top Coal in Hujiahe Coal Mine with the Risk of Rock Burst

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Wenjing Liu ◽  
Deyu Qian ◽  
Xingguo Yang ◽  
Sujian Wang ◽  
Jinping Deng ◽  
...  
Keyword(s):  
Rock Burst ◽  
Coal Mine ◽  
Large Diameter ◽  
Stability Control ◽  
Surrounding Rock ◽  
Shaanxi Province ◽  
Pressure Relief ◽  
Working Face ◽  
Deformation Speed ◽  
Plastic Transformation

Rock burst is a typical dynamic disaster in deep underground coal mining. Based on the support problems of the deep roadways in fully mechanized caving face 401111 of Hujiahe Coal Mine suffering from rock burst in Shaanxi Province of China, the failure law and influencing factors of the surrounding rock of the roadway are analyzed. The results show that the deformation of surrounding rock in the roadway shows the characteristics of elastic, plastic transformation, rheology, and expansion. At the same time, it has the typical characteristics of deep roadway, such as the fast deformation speed, long duration, asymmetric deformation, and large loose broken area of surrounding rock. Based on the principle of “strengthening support in shallow zones” and “deep pressure relief in deep zones” in the surrounding rock, the control scheme of surrounding rock in the return roadway of fully mechanized caving working face 401111 is proposed by taking the large diameter pressure relief and deep hole blasting as the main means of pressure relief. The practice shows that the surrounding rock of the return roadway is relatively stable after the implementation of the new scheme, which shows that the design of the new support scheme is reasonable and reliable. It is of great significance for the stability control of surrounding rock of the mining roadway suffering from rock burst.

scholarly journals Analysis of pressure relief effect of borehole in rock burst mine

2021 ◽  
Author(s):  
Pengbo Xu ◽  
Junjie Shao ◽  
Dong Fan ◽  
Jianghua Chang ◽  
Ning Zhang
Keyword(s):  
Rock Burst ◽  
Pressure Relief ◽  
Relief Effect

scholarly journals Study on the Key Technology of Controlling the Instability of Deep High-Stress Coal and Rock Mass and Relieving the Danger

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhijing Zhang ◽  
Jianghong Zuo ◽  
Dongji Lei
Keyword(s):  
Rock Mass ◽  
Coal Seam ◽  
Rock Fracture ◽  
Mine Safety ◽  
Detection Accuracy ◽  
Pressure Relief ◽  
Rock Body ◽  
Thick Coal Seam ◽  
Before And After ◽  
Relief Effect

In order to solve the problem of stress concentration and gas overrun in the process of uncovering high gas and thick coal seam, combined with the occurrence characteristics of coal seams in Wuyang Coal Mine, the measures of “hydraulic and mechanical cavity making + steel screen pipe + surrounding rock grouting” are adopted to establish a method for mutual verification of multiple effect test indexes of residual stress, residual gas content, coal seam moisture content, and microseismic signal characteristics, and the three-dimensional accurate analysis of the influence range of hydraulic cavitation is effectively realized. By comparing and analyzing the gas extraction amount, the surrounding borehole stress change and the microseismic monitoring signals before and after the application of hydraulic cavitation technology are studied. The results show the following. (1) The pressure relief effect of the hydraulic cavity on surrounding coal decreases with the increase of distance, and the pressure relief effect is most obvious at 1.0∼2.5 m, in the range of 2.5–3.5 m around the hydraulic drilling hole, the duration, rate, and amplitude of pressure relief are reduced compared with those in the range of less than 2.5 m, while in the range of more than 3.5 m, the effect of pressure relief is very weak. (2) During the period of hydraulic cavitation release hole, the radius of water supply to coal seam is within 1.5 m, which accounts for 79% of coal wall area. (3) It is also a process where the stress distribution in the coal and rock body needs to be rebalanced before and after hydraulic caverning, which is often accompanied by microfracture of coal and rock mass. The analysis shows that, before hydraulic caverning, the waveform of coal and rock fracture signal has a short duration, large amplitude, and obvious signal mutation, and the dominant frequency of the signal is about 250 Hz, with large total energy. After hydraulic caverning, the intensity of coal and rock fracture events is greatly reduced. The research results can effectively identify the influence range of hydraulic cavitation, improve the detection accuracy and efficiency of hydraulic cavitation range, effectively predict and warn the hidden danger of mine safety, and provide a reference for the work of similar mines.

scholarly journals Study on Failure Characteristics and Rock Burst Mechanism of Roadway Roof under Cyclic Dynamic Load

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Chunmei Zheng ◽  
Jiayan Zheng ◽  
Xiaojuan Peng ◽  
Lei Zhou
Keyword(s):  
Rock Mass ◽  
Rock Burst ◽  
Dynamic Load ◽  
Control Function ◽  
Surrounding Rock ◽  
Strong Impact ◽  
Large Area ◽  
Rock Destruction ◽  
Supporting Structure ◽  
Cyclic Dynamic

Rock burst is a catastrophic phenomenon that often occurs in underground rock mass engineering. In order to reveal the essence of rock burst of a hard roof in the process of roadway excavation, the particle discrete element method is used to establish a roadway model and simulate the disturbance of harmonic dynamic load based on the analysis of a rock burst accident in a deep mine. The crack field, stress field, displacement field, and kinetic energy of roadway surrounding rock disturbed by cyclic dynamic load were analyzed, and the disaster mechanism of roadway impacting roof instability was discussed. The results show that, compared with the roadway support structure under static load that can give full play to its control function of surrounding rock, the roadway surrounding rock will collapse and lose stability in a large area under the roof cyclic dynamic load, and the ordinary supporting structure cannot give full play to its control function of surrounding rock, resulting in the surrounding rock destruction and supporting structure failure. In addition, the essence of rock burst in a hard thick roof is due to the instantaneous superposition of static stress and dynamic load, leading to the instantaneous instability and collapse of roadway roof in a large area. The research is of great significance to further understand the deformation and failure mechanism of roadway surrounding rock under strong impact load, to guide the safe production and prevent the occurrence of rock burst hazard in underground rock mass engineering.

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