scholarly journals Disaster Control of Roof Falling in Deep Coal Mine Roadway Subjected to High Abutment Pressure

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Shizhong Zhang ◽  
Gangwei Fan ◽  
Ling Chai ◽  
Qizhen Li ◽  
Mingwei Chen ◽  
...  
Keyword(s):  
Coal Mine ◽  
Abutment Pressure ◽  
Mechanical Analysis ◽  
Stability Control ◽  
Surrounding Rock ◽  
Effective Control ◽  
Column Length ◽  
Disaster Control ◽  
Roof Falling ◽  
Hydraulic Supports

The roof falling accident is a serious threat to the lives of miners in deep coal mining, especially when the coal mine is more than 1000 meters deep. In regard to the 5306 coalface in the Tangkou coal mine, Shandong, China, the depth of coal seam is 992.8 m and the stress concentration coefficient of the roadway surrounding rock is 3.33. This leads to a serious deformation of the roadway roof, thereby producing a high risk of the roof falling disaster. In this pursuit, based on the mechanical analysis of roadway roof subjected to a high abutment pressure, the mathematical expressions of the setting load and movable column length of supports were introduced. Furthermore, the stability control mechanism of the roadway roof was analyzed and the optimized support parameters of supports are provided. The results showed that the longtime effective support of the roadway roof required the strength and deformation coupling of supports and anchored surrounding rock. The support length of the belt roadway should be at least 57.7 m, with 0-30 m away from the coalface supported by hydraulic supports and 32-57.7 m supported by single props. In addition, the maximum setting load and movable column length of hydraulic supports were 21.67 MPa and 280.3 mm and 12.44 MPa and 177.1 mm for single props, respectively. By applying the optimized support parameters of supports to the belt roadway of the 5306 coalface, the effective control of the roadway roof and the disaster control of roof falling were realized.

scholarly journals Study on the Migration Law of Overlying Strata of Gob-Side Entry Retaining Formed by Roof Cutting and Pressure Releasing in the Shallow Seam

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Chen Tian ◽  
Anhu Wang ◽  
Yingjie Liu ◽  
Tinggui Jia
Keyword(s):  
Coal Mine ◽  
Vertical Displacement ◽  
Mechanical Analysis ◽  
Stability Control ◽  
Surrounding Rock ◽  
Hard Coal ◽  
Cutting Angle ◽  
Maximum Angle ◽  
Roadway Stability ◽  
Cutting Height

A mechanical model of a hard roof was built to analyze the pressure relief roof cutting (RCPR) process for gob-side entry retaining (GER) and identify the critical stage of roadway stability control during RCPR. Based on the mechanical analysis of key parameters of automatic roadway with RCPR, the FLAC3D software was adopted to conduct a numerical simulation to investigate the influence law of height and angle of RCPR, to analyze the trend of variations in the vertical displacement of roadway surrounding rock stress and the roof under different conditions, and to verify that the optimal roof cutting height and seam cutting angle of the 12201 working face of Halagou Coal mine are 6 m and 20°, respectively. The effect of automatic roadway with RCPR has been well implemented through conducting the bidirectional cumulative blasting test on site. To impose effective roadway surrounding rock controlling measures on Halagou Coal mine in RCPR of hard, coal-bearing roof structures at a shallow mining depth, constant resistance large deformation anchor cables, in combination with a single hydraulic prop, joist steel 11#, and steel mesh reinforcement, could provide active surrounding rock support. In addition to the active support, surrounding rock control could be strengthened using grouting bolts. Based on the result, the stress in the roadway coal side and the vertical displacement of the roof can be reduced through increasing the roof cutting height, contributing to the stability of the roadway. Increasing of the roof cutting angle will lead to the increasing of stress in the coal side of the roadway and the increasing of roof displacement with a maximum angle of 20°. Meanwhile, the peak of stress concentrating on both sides of the extreme angle is decreased. Thus, increasing the cutting roof angle at random can be unfavorable to the management of roadway roof. To develop RCPR GER, roadway surrounding rock requires greater support when the mine face passes through a cutting slot. After industrial trials, these measures are proved to be effective in controlling surrounding rock movement and developing GER.

Reasonable Entry Layout of Lower Seam in Multi-Seam Mining Based on Numerical Simulation

2013 ◽  
Vol 295-298 ◽  
pp. 2980-2984
Author(s):  
Xiang Qian Wang ◽  
Da Fa Yin ◽  
Zhao Ning Gao ◽  
Qi Feng Zhao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Coal Seam ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Geological Conditions ◽  
Seam Mining

Based on the geological conditions of 6# coal seam and 8# coal seam in Xieqiao Coal Mine, to determine reasonable entry layout of lower seam in multi-seam mining, alternate internal entry layout, alternate exterior entry layout and overlapping entry layout were put forward and simulated by FLAC3D. Then stress distribution and displacement characteristics of surrounding rock were analyzed in the three ways of entry layout, leading to the conclusion that alternate internal entry layout is a better choice for multi-seam mining, for which makes the entry located in stress reduce zone and reduces the influence of abutment pressure of upper coal seam mining to a certain extent,. And the mining practice of Xieqiao Coal Mine tested the results, which will offer a beneficial reference for entry layout with similar geological conditions in multi-seam mining.

scholarly journals Deformation Rules for Surrounding Rock in Directional Weakening of End Roofs of Thin Bedrocks and Ultrathick Seams

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Fei Liu ◽  
Zhanguo Ma ◽  
Yongsheng Han ◽  
Zhimin Huang
Keyword(s):  
Abutment Pressure ◽  
Main Roof ◽  
Stability Control ◽  
Surrounding Rock ◽  
Western China ◽  
Resource Exploitation ◽  
Failure Characteristics ◽  
Key Strata ◽  
Working Face ◽  
Geological Conditions

With the deployment of China’s energy strategy in the western regions, complex geological mining conditions such as thin bedrock and ultrathick seams in western China have caused a series of problems such as serious deformation of the surrounding rock at the ends of the working face and the increase in the lead abutment pressure of the roadways; the research on end roof deformation in the resource exploitation in western China has become one of the great demands of the industry. Based on the failure characteristics of rock mass, relying on the actual mining geological conditions of a coal mine in Inner Mongolia, the failure characteristics of the overlying rock strata under the influence of mining were simulated and analyzed using similar material simulation experiment, which intuitively reproduced the failure and deformation processes of the immediate roof, main roof, and key strata and revealed the mechanical mechanism of the directional weakening of the end roof. It is of great significance for the stability control of the surrounding rock at the end of the fully mechanized caving face in the thin bedrocks and ultrathick seams, reducing the abutment pressure of gate roadway and controlling the spontaneous combustion of residual coal in the goaf.

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.

Investigation on Deformation and Failure Characteristics and Stability Control of Soft Rock Roadway Surrounding Rock in Deep Coal Mine

2011 ◽  
Vol 255-260 ◽  
pp. 3711-3716 ◽  
Author(s):  
Ju Cai Chang ◽  
Guang Xiang Xie
Keyword(s):  
Coal Mine ◽  
Plastic Region ◽  
Soft Rock ◽  
Stability Control ◽  
Surrounding Rock ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Deep Coal Mine ◽  
Soft Rock Roadway ◽  
Rock Roadway

Numerical simulation and field measurement were carried out to investigate into laws of deformation and movement and the evolving characteristics of the plastic region around the roadway based on engineering conditions of deep soft rock roadway in Wangfenggang colliery, Huainan Mining area. The mechanism of controlling the surrounding rock stability of soft rock roadway in deep coal mine was demonstrated. The supporting of soft rock roadway in deep coal mine must be compatible with deformation and failure characteristics of surrounding rock, and it can keep the stability of surrounding rock. The combined supporting with high strength and prestress bolting-anchoring and integral surrounding rock grouting reinforcement can effectively control the surrounding rock deformation of soft rock roadway in deep coal mine. But every working step must be pay attention to sequence on the time and space so that it can play an integral supporting effect. Research results are put into practice accordingly and good control effect has been achieved.

Deformation Failure Analysis and Stability Control Technology of Large Section Soft Rock Chamber in Deep Coal Mine

2013 ◽  
Vol 353-356 ◽  
pp. 1035-1039
Author(s):  
Chang Hui An ◽  
Gui Bin Zhang ◽  
Zhi Da Liu ◽  
Kai Zhao ◽  
Wei Guo ◽  
...  
Keyword(s):  
Coal Mine ◽  
Soft Rock ◽  
Stability Control ◽  
Surrounding Rock ◽  
Mine Safety ◽  
Large Section ◽  
Deformation And Failure ◽  
Deep Coal Mine ◽  
Ground Pressure ◽  
The Impact

The chambers of certain coal mine in Shandong such as central substation situate in soft rock which consists of mudstone and fine sandstone, etc. Obvious ground pressure behaviors, large deformation and failure of surrounding rock have serious effect on mine safety production, with the impact of various complicated deep large ground pressure. This paper presents a rational scheme to control the surrounding rock steadily, based on analysis of deformation and failure on large section soft rock chamber, combined with the concept of the" combined supporting technology of long and short anchors" and "the combined supporting technology of three anchors".

scholarly journals Investigation of Mechanical Properties for Group Anchors

2021 ◽  
Vol 11 (4) ◽  
pp. 1521
Author(s):  
Juncai Cao ◽  
Nong Zhang ◽  
Shanyong Wang ◽  
Qun Wei
Keyword(s):  
Bearing Capacity ◽  
Coal Mine ◽  
Design Method ◽  
Stability Control ◽  
Surrounding Rock ◽  
Physical Test ◽  
Anchor Structure ◽  
The Stability ◽  
Mine Roadways ◽  
Prestressed Anchor

Prestressed anchor support is one of the most important support methods for coal mine roadways. As the coal mining depth increases, the adaptability of existing prestressed anchor has become weaker and weaker, which is mainly reflected in the current anchor prestress is much smaller than the support resistance required for the stability of the roadways and makes it difficult to effectively control the roadways. In order to solve the problem, a group anchor structure was proposed to realize higher prestressed anchor support technology and improve the support status of deep roadways. For coal mine roadways, group anchor structure is a new technology and new topic, and the design method and theoretical basis of the group anchor support are lacking. Therefore, the paper studied the bearing capacity of the group anchors through physical tests and numerical simulations. Among them, a special set of group anchor drawing tooling was designed and processed to match the physical test. The test results show that the group anchor structure can double the bearing capacity and bearing rigidity compared with traditional anchors, and the group anchor support can further optimize the support parameters to improve the bearing capacity of the surrounding rock. Therefore, the group anchor support is helpful to the stability control of the surrounding rock of the deep roadway.

scholarly journals Relationship between advancing abutment pressure and deformation of surrounding rock in a roadway: A case study in Helin coal mine in China

2021 ◽  
Author(s):  
Hongyan Qin ◽  
Zhiheng Cheng ◽  
Zhenhua Ouyang ◽  
Xidong Zhao ◽  
Jicheng Feng
Keyword(s):  
Large Deformation ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Small Deformation ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Deformation Stage ◽  
Original Rock ◽  
Rapid Deformation ◽  
Peak Value

Abstract The deformation stages of the working face of a mine in front of the roadway were defined based on the location of the roadway and the coal wall in different deformation zones. Observational data of the advancing abutment pressure and the surrounding rock deformation of the roadway from Helin coal mine were analyzed using least squares fitting. The results show that the distance between the boundary of the rapid deformation stage and the deceleration deformation stage and the position where the advancing abutment pressure is equal to the original rock stress is 0.8 m. The distance between the boundary of the large deformation stage and the stable small deformation stage and the peak value of the advancing abutment pressure is 0.3 m. A theoretical analysis indicated that the boundary between the rapid deformation stage and the deceleration deformation stage is located at the intersection of the advancing abutment pressure curve and the original rock stress curve. The boundary between the large deformation stage and the stable small deformation stage is located at the peak value of the advancing abutment pressure.

Pre-Reinforcement Technology in Broken Roof Side Condition

2012 ◽  
Vol 215-216 ◽  
pp. 681-684
Author(s):  
Yu San Shen ◽  
Li Jun Zeng
Keyword(s):  
Coal Mine ◽  
Abutment Pressure ◽  
Geological Structure ◽  
Surrounding Rock ◽  
Security Risks ◽  
Side Condition ◽  
Supporting Effect ◽  
The Way

The roof side broken brings serious security risks in the construction in coal mine. The geological structure of faults and folds that encountered in coal mine and the affect of abutment pressure in the goaf creat roof side broken. If in the way of reinforced support to control the surrounding rock, it is difficult to achieve the expected security. Especially if the roof side broken appears in the mining gateway, controlling the surrounding rock by the way of reinforced support causes waste of materials and the supporting effect is limited. So, combined with the distribution of abutment pressure of the surrounding rock in broken roadway, starting from the nature change of the surrounding rock, through injection of Malisan to change the broken condition of surrounding rock, the broken roadway is effectively.under control.

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