scholarly journals Deformation and Failure Characteristics and Control Technology of Roadway Surrounding Rock in Deep Coal Mines

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Jucai Chang ◽  
Dong Li ◽  
Tengfei Xie ◽  
Wenbao Shi ◽  
Kai He
Keyword(s):  
High Stress ◽  
Development Stage ◽  
Surrounding Rock ◽  
Deformation And Failure ◽  
Deformation Stage ◽  
Mining Depth ◽  
Floor Heave ◽  
Rock Tunnel ◽  
Two Sides

With the increase in mining depth, the problem of the floor heave of a roadway is becoming increasingly prominent. Solving this problem for a deep high-stress roadway is the key to ensure safe supply and utilization of coal resources in China. This study investigates the floor heave of a horizontal transportation rock roadway at the depth of 960 m at the Xieyi Mine. A four-way loading simulation test frame similar to the Xieyi Mine was used to reproduce the high-stress environment of a deep roadway by loading different pressures on the roof, floor, and two sides of the roadway. The experimental results show that after the tunnel had been excavated, the surrounding rock failure could be divided into three stages: the initial deformation stage, fissure development stage, and mild deformation stage. The destruction time periods of these stages were 0–0.5 h, 0.5–2 h, and 2–6 h, and the destruction ranges were 0.4 m, 1 m, and 1.5 m, respectively. The amount of roof subsidence, the displacement of the two sides, and the floor heave influence each other, and the range of the bearing ring (5.6 m) of the floor is larger than that of the roof (3.4 m) after the surrounding rock has been damaged. The findings suggest that the floor should be supported first, before the two sides and the roof; then, the support of the key parts (roof and floor corners) should be strengthened. The roof, floor, and two sides are considered for controlling the deformation of the surrounding rock in a coupled trinity support mode. Because of the unfavorable conditions in the area, overexcavation backfill technology was used. The new support was successfully applied during the subsequent construction of the rock tunnel. Based on the long-term monitoring results of the surrounding rock deformation, the floor heave control yielded satisfactory results and maintained the long-term stability of the roadway. Therefore, this study can serve as a reference for preventing floor heave in similar high-stress roadways in the future.

scholarly journals Experimental Test on Nonuniform Deformation in the Tilted Strata of a Deep Coal Mine

2021 ◽  
Vol 13 (23) ◽  
pp. 13280
Author(s):  
Hai Wu ◽  
Qian Jia ◽  
Weijun Wang ◽  
Nong Zhong ◽  
Yiming Zhao
Keyword(s):  
High Stress ◽  
Stability Control ◽  
Surrounding Rock ◽  
Experimental Results ◽  
Lower Side ◽  
Reinforcement Scheme ◽  
Deformation And Failure ◽  
True Triaxial ◽  
Deep Mine ◽  
Deep Coal Mine

Taking a deep-mine horizontal roadway in inclined strata as our research object, the true triaxial simulation technique was used to establish a model of the inclined strata and carry out high-stress triaxial loading experiments. The experimental results show that the deformation of surrounding rock in the roadway presents heterogeneous deformation characteristics in time and space: the deformation of the surrounding rock at different positions of the roadway occurs at different times. In the process of deformation of the surrounding rock, deformation and failure occur at the floor of the roadway first, followed by the lower shoulder-angle of the roadway, and finally the rest of the roadway. The deformation amount in the various areas is different. The floor heave deformation of the roadway floor is the greatest and shows obvious left-right asymmetry. The deformation of the higher side is greater than that of the lower side. The model disassembly shows that the development of cracks in the surrounding rock is characterized by more cracks on the higher side and fewer cracks on the lower side but shows larger cracks across the width. The experimental results of high-stress deformation of the surrounding rock are helpful in the design of supports, the reinforcement scheme, and the parameter optimization of roadways in high-stress-inclined rock, and to improve the stability control of deep high-stress roadways.

Of forming loads on the mounting of shaft shafts in the hierarchic block environment under the influence of modern geodynamic movements

2020 ◽  
pp. 161-169
Author(s):  
I. L. Ozornin ◽  
A. E. Balek ◽  
A. N. Kaiumova
Keyword(s):  
Rock Mass ◽  
High Stress ◽  
Surrounding Rock ◽  
Strain Behavior ◽  
Underground Openings ◽  
Hierarchical Block Structure ◽  
The Subject ◽  
Nonuniform Stress Field ◽  
Strength Rock

The subject of the research is the lining of mine shafts and surrounding rock mass. The subject matter is the features of the stress-strain behavior of lining and adjacent rock mass in shafts and near-shaft underground openings in the Tenth Anniversary of Independence of Kazakhstan mine located in the tectonically high-stress and low-strength rock mass. The loading of the lining in the shafts and near-shaft openings in the Tenth Anniversary of Independence of Kazakhstan mine during construction is investigated, and the damages of the lining in the course of drivage in the nonuniform stress field are analyzed. The long-term periodic in-situ instrumental monitoring of stress variation in the lining of the mine shafts and near-shaft openings revealed the main influences on the process of load formation on the lining in the conditions of post-limiting deformation of surrounding rock mass. It is validated that the surrounding rock mass of the mine has a complex hierarchical block structure and is subjected to modern geodynamic movements. As the depth of mining is increased, surrounding rock mass of the mine shafts transfers to the condition of postlimiting stresses and strains. As a consequence, the lining of the shafts and near-shaft openings at different stages of construction experiences nonuniform concentrated loads, which violates integrity of the lining.

Study on the Application of Bolt-Grout Reinforcement in the Deep Soft Rock Roadway

2011 ◽  
Vol 90-93 ◽  
pp. 1956-1959 ◽  
Author(s):  
Zhi Lin Dun ◽  
Da Shuai Ren ◽  
Lian Wei Ren
Keyword(s):  
Soft Rock ◽  
Field Monitoring ◽  
Surrounding Rock ◽  
Geological Condition ◽  
Mining Depth ◽  
Air Inlet ◽  
Strata Behavior ◽  
Soft Rock Roadway ◽  
Two Sides ◽  
Rock Roadway

With the increasement of mining depth, the strata behavior of the roadway is obvious. As the stress of surrounding rock increases, the bottom of the soft rock roadway becomes deformed easily compressed by its top rock and two sides rock, which leads to the occurrence of the pucking and roadway destruction. Aiming the air inlet roadway destruction phenomenon of -450th level powder magazine in Hebi Zhongtai Mining Co.Ltd, the geological condition and the mechanism of the roadway failure are analysed comprehensively, and the bolt-grout supporting method is also proposed in this paper. At last, the deformation and heaving floor are controlled effectively which is proved by the field monitoring results.

scholarly journals Research on Control Mechanism of Surrounding Rock of Deep Gob-Side Entry Retaining

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jianxiong Liu ◽  
Jingke Wu ◽  
Yun Dong ◽  
Yanyan Gao ◽  
Jihua Zhang ◽  
...  
Keyword(s):  
Large Deformation ◽  
High Stress ◽  
Original System ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Eccentric Load ◽  
Deformation And Failure ◽  
Body Fracture ◽  
Stress States ◽  
Term Creep

To address the large deformation of the surrounding rock of deep gob-side entry retaining under high stress, lithological characteristics of the surrounding rock and failure model of support body and their evolutionary processes are analyzed through field investigation and theoretical analysis. Failure mechanisms of surrounding rock and the technology to control it are studied systematically. The results show that the causes of the large deformation of the surrounding rock are weak thick mudstones with softening property and water absorption behavior, as well as its fragmentation, dilatancy, and long-term creep during strong disturbance and highly centralized stress states. The cross-section shape of the roadway after deformation and failure of the surrounding rock is obviously asymmetric in both the horizontal and vertical directions. Since the original system supporting the surrounding rock is unable to completely bear the load, each part of the supporting system is destroyed one after the other. The failure sequences of the surrounding rock are as follows: (1) roadway roof fracture in the filling area, (2) filling body fracture under eccentric load, (3) rapid subsidence of the roadway roof, and (4) external crack drum and rib spalling at the solid coal side. Due to this failure sequence, the entire surrounding rock becomes unstable. A partitioned coupling support and a quaternity control technology to support the surrounding rock are proposed, in which the roof of the filling area plays a key role. The technology can improve the overall stability of gob-side entry retaining, prevent support structure instability caused by local failure of the surrounding rock, and ensure the safety and smoothness of roadways.

Analysis of Soft Rock Tunnel Mechanics Effects Based on Strain Softening Model of Surrounding Rock

2012 ◽  
Vol 424-425 ◽  
pp. 520-525
Author(s):  
Jie Hong Zhang
Keyword(s):  
Numerical Analysis ◽  
Strain Softening ◽  
Mechanical Response ◽  
High Stress ◽  
Soft Rock ◽  
Mechanical Effect ◽  
Surrounding Rock ◽  
Plastic Range ◽  
Construction Design ◽  
Rock Tunnel

Aiming at mechanical response of soft surrounding tunnel affected by high stress, the mechanical effect in the process of excavation and supporting of surrounding rockmass was analyzed by softening model. First of all, mechanics properties of soft surrounding rock and strain softening model have been discussed. Then, based on strain softening model, numerical analysis was carried out, and stress and displacement field, plastic range in the in the process of excavation and supporting was obtained. The result was very useful for the optimization of construction design and perfection for supporting program.

scholarly journals Field and Numerical Study on Deformation and Failure Characteristics of Deep High-Stress Main Roadway in Dongpang Coal Mine

2021 ◽  
Vol 13 (15) ◽  
pp. 8507
Author(s):  
Shuaigang Liu ◽  
Jianbiao Bai ◽  
Xiangyu Wang ◽  
Shuai Yan ◽  
Jiaxin Zhao
Keyword(s):  
Field Test ◽  
Negative Impact ◽  
Numerical Study ◽  
Coal Mines ◽  
High Stress ◽  
Damage Parameter ◽  
Surrounding Rock ◽  
Repair Work ◽  
Deformation And Failure ◽  
Crack Distribution

Deep horizontal high stress and high permeability geological factors appear when coal mines are converted to deep horizontal mining. When the roadway is damaged by the mining face, and the supporting components are mismatched, the deep roadways necessitate extensive repair work, which has a negative impact on the coal mining economy and sustainability. This paper carried out a series of field tests on the roadways deformation, crack distribution, and loose rock zone of the deep roadways. Furthermore, a numerical calculation model was established using the discrete element method (DEM) and calibrated with laboratory tests and RQD methods. Both the stress and crack distribution in the surrounding rock of the deep roadway were simulated. The field test and the corrected numerical model showed consistency. A FISH function was used to document the propagation of shear and tensile cracks around the roadway in three periods, and a damage parameter was adopted to evaluate the failure mechanism of the deep roadways under the dynamic stress disturbance. The matching of specifications of anchor cables, rock bolts, and anchoring agent is the primary point in the control of deep roadways, and revealing the stress evolution, crack propagation, and damage distribution caused by mining effects is another key point in deep roadway controlling. The field test and DEM in this paper provide a reference for the design of surrounding rock control of deep roadways and the sustainable development of coal mines.

scholarly journals Research and Application of Directional Roof Cutting and Pressure Releasing Technology for Retracement Channel of 3314 Working Face in Hexi Coal Mine

2021 ◽  
Author(s):  
Jindong Cao ◽  
Xiaojie Yang ◽  
Ruifeng Huang ◽  
Qiang Fu ◽  
Yubing Gao
Keyword(s):  
Coal Mine ◽  
High Stress ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Mine Pressure ◽  
Working Face ◽  
Geological Conditions ◽  
Cutting Effect ◽  
The Stability ◽  
Two Sides

Abstract The high stress of the surrounding rock of Hexi Coal Mine easily leads to severe deformation of the retracement channel and the appearance of the mine pressure during the retreat severely affects the stability of the roadway. In order to solve the above problems, a roadway surrounding rock control technology is proposed and tested. The bidirectional energy-concentrated tensile blasting technology is used to perform directional cutting to cut off the stress propagation path. Firstly, the deformation mechanism of the roof is analyzed by establishing the deformation mechanical model of the roof of the retracement channel. Then, according to the geological conditions of working face 3314 and theoretical calculation, the key parameters of roof cutting and pressure releasing of retracement channel are determined, and through the numerical analysis of its cutting effect, the length of cutting seam is 11.5m, and the cutting angle is 10°. Finally, a field test is carried out on the retracement channel of 3314 working face to verify the effect of roof cutting. The results show that the deformation of the retracement channel and the main roadway is very small. In the process of connecting the working face and the retracement channel, the maximum roof to floor convergence is 141mm, and the two sides convergence is 79mm. After the hydraulic support was retracted, the maximum roof to floor convergence of the surrounding rock is 37 mm, and the two sides convergence is 33mm. The roof cutting and pressure releasing of the retracement channel ensures the safe evacuation of the equipment and the stability of the main roadway. The cutting effect is obvious for the release of pressure, which is of great significance to engineering practice.

scholarly journals Deformation Mechanism and Control Technology of the Surrounding Rock of the Floor Roadway under the Influence of Mining

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Qingchong Zhao ◽  
Baojie Fu ◽  
Jiadi Yin
Keyword(s):  
Numerical Simulation ◽  
Surface Displacement ◽  
Surrounding Rock ◽  
Infinite Body ◽  
Maximum Displacement ◽  
Deformation And Failure ◽  
Working Face ◽  
Before And After ◽  
Stress And Deformation ◽  
Two Sides

Deformation and failure mechanism of the surrounding rock of the floor roadway under the influence of working face mining is complicated, and roadway control is difficult. The floor roadway of the 11123 working face in Pan’er Mine is taken as the research object of this study based on semi-infinite body theory of elastic mechanics to establish a mechanical model along the advancing direction of the working face and derive the stress expression of any point in the affected area of floor mining. According to the theoretical results, effective reinforcement and support schemes are then proposed. FLAC3D numerical simulation analyzes the stress and deformation of the surrounding rock of the floor roadway before and after the reinforcement. The numerical simulation results showed that (1) mining abutment pressure of the overlying working face forms a certain range of stress concentration on the roof and two sides of the roadway and will cause deformation and damage to the floor roadway and (2) overall bearing capacity of the surrounding rock of the roadway is significantly improved, and surface displacement of the floor roadway is reduced by 64 mm through the reinforcement and support of the floor roadway. On-site monitoring data of the floor roadway in the 11123 working face of Pan’er Mine showed that the maximum displacement of the roadway roof and two sides is controlled at approximately 80 mm, and the surrounding rock deformation of the roadway is appropriately controlled to meet the needs of safe production.

scholarly journals Study on Mechanical Mechanism and Stability of Surrounding Rock in Fault Structure Roadway

2021 ◽  
Author(s):  
yuming lu ◽  
Wang Wei ◽  
Tang Zhiyu1
Keyword(s):  
Field Investigation ◽  
Surrounding Rock ◽  
Metal Mesh ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Fault Structure ◽  
Long Term Stability ◽  
Before And After ◽  
Calculation Results

Abstract In order to study the deformation and failure mechanism of the fault passage, this paper makes a series of research on the fault passage through theoretical analysis, field investigation and numerical simulation. Firstly, the mechanical characteristics of the fault structure and the deformation and failure characteristics of the surrounding rock passing through the fault are summarized. Then, the numerical analysis is carried out before and after the tunnel passing through the fault. The results show that the original support scheme has large deformation and failure in the surrounding rock of the fault section, and the deterioration and expansion of the plastic zone leads to the failure of the support. Finally, the comprehensive support scheme and principle of "bolt + anchor cable + metal mesh + grouting" is put forward, and the support for the broken tunnel passing through the fault is strengthened. The calculation results show that the support scheme can keep the tunnel passing through the fault in a stable deformation range, which is conducive to the long-term stability of the surrounding rock.

scholarly journals Research on the Law of Large-Scale Deformation and Failure of Soft Rock Based on Microseismic Monitoring

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Feng Chen ◽  
Tianhui Ma ◽  
Chun’an Tang ◽  
Yanhong Du ◽  
Zhichao Li ◽  
...  
Keyword(s):  
Monitoring System ◽  
Large Scale ◽  
Failure Process ◽  
Soft Rock ◽  
Microseismic Monitoring ◽  
Surrounding Rock ◽  
Deformation And Failure ◽  
Microseismic Events ◽  
Rock Tunnel ◽  
Microseismic Event

Based on the existing Canadian ESG microseismic monitoring system, a mobile microseismic monitoring system for a soft rock tunnel has been successfully constructed through continuous exploration and improvement to study the large-scale nucleation and development of microfractures in the soft rock of the Yangshan Tunnel. All-weather, continuous real-time monitoring is conducted while the tunnel is excavated through drilling and blasting, and the waveform characteristics of microseismic events are analysed. Through the recorded microseismic monitoring data, the variation characteristics of various parameters (e.g., the temporal, spatial, and magnitude distributions of the microseismic events, the frequency of microseismic events, and the microseismic event density and energy) are separately studied during the process of large-scale deformation instability and failure of the soft rock tunnel. The relationship between the deterioration of the rock mass and the microseismic activity during this failure process is consequently discussed. The research results show that a microseismic monitoring system can be used to detect precursors; namely, the microseismic event frequency and energy both will appear “lull” and “active” periods during the whole failure process of soft rock tunnel. Two peaks are observed during the evolution of failure. When the second peak occurs, it is accompanied by the destruction of the surrounding rock. The extent and strength of the damage within the surrounding rock can be delineated by the spatial, temporal, and magnitude distributions of the microseismic events and a microseismic event density nephogram. The results of microseismic analysis confirm that a microseismic monitoring system can be used to monitor the large-scale deformation and failure processes of a soft rock tunnel and provide early warning for on-site construction workers to ensure the smooth development of the project.

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