ArticlePublisher preview available

High-Stress Chamber Stability in Kilometer-Deep Coal Mines: A Case Study

Authors:
Jin-xiao Liu
Jin-xiao Liu
Jin-xiao Liu
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Yi-ning Zheng
Yi-ning Zheng
Yi-ning Zheng
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Ren-Bao Zhao
Ren-Bao Zhao
Ren-Bao Zhao
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Sheng-shi Meng
Sheng-shi Meng
Sheng-shi Meng
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Show all 6 authorsHide
Read publisher preview
Download citation
To read the full-text of this research, you can request a copy directly from the authors.

Abstract and Figures

Controlling the surrounding rock of coal mine roadways or chambers becomes more difficult as mining depth increases. The stability of the underground chamber complex, as an transportation hub and power center, is one of the main focuses of coal mine development. The case study is raised to control the surrounding rock of deep buried chamber complex. The examine become finished at the 2nd extraction phase in a deep coal mine, and the pillar stability turned into analyzed. The narrow pillar allows for a high diploma of stress superposition all through excavation of adjacent chambers. Based on the stress state of deep chambers, the “Yielding rock bolt—Grouting anchor cable and Concrete spraying layer” support scheme became proposed. The field application consequences show that the displacement of the pump room is 60 mm, which is within the acceptable range. The Support Vector Machine was used to evaluate the stability of the chamber and showed good result. The technique can be applied to the excavation and support of high stress chamber station in coal mines.
Figures - available from: Geotechnical and Geological Engineering
This content is subject to copyright. Terms and conditions apply.
A preview of this full-text is provided by Springer Nature.
Learn more
Content available from Geotechnical and Geological Engineering
This content is subject to copyright. Terms and conditions apply.
Vol.: (0123456789)
1 3
Geotech Geol Eng (2024) 42:2425–2438
https://doi.org/10.1007/s10706-023-02682-4
ORIGINAL PAPER
High‑Stress Chamber Stability inKilometer‑Deep Coal
Mines: ACase Study
Jin‑xiaoLiu· Yi‑ningZheng· Ren‑BaoZhao·
Sheng‑shiMeng· Yong‑leLiu· ChangSun
Received: 5 January 2023 / Accepted: 21 October 2023 / Published online: 20 November 2023
© The Author(s), under exclusive licence to Springer Nature Switzerland AG 2023
Keywords Chamber complex· High stress·
Yielding bolt· Support technology
1 Introduction
The chamber complex is among the most important
underground mining roadway systems thanks to its
enormous cross-sections and strict links to adja-
cent roadways. After excavation of the chamber, the
stresses are redistributed and sub-sequence stresses
appear. The stability of a chamber is defined as the
deformation and damage characteristics that occur
in the surrounding rock. The coupling of various
stresses exacerbates the complexity of the engineer-
ing condition. The examination of each certain issue
serves as the foundation for designing the placement
and support of deep constructed chamber complexes.
The rock excavation produces a transfer and con-
centration of stresses, which deteriorates the stress
state of the chamber and its adjacent structures
(Zhang et al. 2020). Bandini et al. (2017) stressed
the importance of constructing a safety engineering
system. The finite and distinct element methods are
applied to analyze the stability of underground pow-
erhouse in recent years. Hu etal. (2022) created a 3D
FEM model for the cavern group’s excavation pro-
cess, which considered the project’s structural char-
acteristics. Wei etal. (2022) used DFN to study the
effect of fractures on tunnel excavation. The dip angle
Abstract Controlling the surrounding rock of coal
mine roadways or chambers becomes more difficult
as mining depth increases. The stability of the under-
ground chamber complex, as an transportation hub
and power center, is one of the main focuses of coal
mine development. The case study is raised to control
the surrounding rock of deep buried chamber com-
plex. The examine become finished at the 2nd extrac-
tion phase in a deep coal mine, and the pillar stability
turned into analyzed. The narrow pillar allows for a
high diploma of stress superposition all through exca-
vation of adjacent chambers. Based on the stress state
of deep chambers, the “Yielding rock bolt—Grouting
anchor cable and Concrete spraying layer” support
scheme became proposed. The field application con-
sequences show that the displacement of the pump
room is 60 mm, which is within the acceptable range.
The Support Vector Machine was used to evaluate the
stability of the chamber and showed good result. The
technique can be applied to the excavation and sup-
port of high stress chamber station in coal mines.
J.Liu· Y.Liu· C.Sun(*)
Shandong University ofScience andTechnology, 579
Qianwangang Rd, Huangdao District, Qingdao266590,
China
e-mail: sc942045814@163.com
J.Liu· Y.Zheng· R.-B.Zhao· S.Meng
Luxi Mining Guotun Coal Mini, Shandong Energy,
GuotunTown,Heze274700, China
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
ResearchGate has not been able to resolve any citations for this publication.
Analysis of Structural Characteristics of Underground Cavern Group by Simulating All Cavern Excavation
Article
Full-text available
  • Mar 2022
The traditional Three-dimensional (3D) model for stability analysis of a large underground cavern group only includes the main powerhouse, the main transformer chamber, the tailrace surge tank, the main electrical wire hall, and part of the diversion tunnel and tailwater tunnel. Other caverns excavation are not taken into consideration, which is inconsistent with the actual project. In this study, a 3D Finite Element Method (FEM) model, including all the cavities, and a 3D simplified model containing only part of the cavities were established based on the actual underground cavern group project. We study the structural characteristics of the cavern group during excavation via 3D nonlinear FEM. At the same time, three numerical calculation schemes are designed for comparison. The results show that the simulated distributions of the stress field, deformation field, and plastic zone of the two numerical models are similar, but the magnitudes of the 3D FEM model, which considers all caverns are generally higher than the simplified model. The difference between the two simulated horizontal displacements of the main powerhouse reaches 53.72%. Therefore, from the perspective of engineering safety and actual construction, it is advisable to adopt the 3D FEM model, including all the cavities, when conducting a simulation analysis of the underground cavern group.
View
Stability analysis of fractured rock mass around underground excavations based on a three-dimensional discrete fracture network
Article
Full-text available
  • Feb 2022
  • ENVIRON EARTH SCI
Underground excavation often encountered rock masses embedded with pre-existing fractures. Conventional excavation analysis was generally based on a continuum description. In this study, to investigate the influence of randomly distributed discrete fractures on underground excavation, a finite element modeling approach based on a three-dimensional (3D) discrete fracture network (DFN) was utilized. The influence of fracture parameters including fracture intensity, dip angle and strike on the surrounding rock stability was considered in the simulation. The results suggested that fractures caused complexity in terms of the deformation behavior of rock masses around the underground cavern, facilitated the instability of surrounding rock. The intensity, dip angle and strike of fractures had different effects on the stress, displacement and failure modes of the jointed rock masses. The fracture intensity mainly affected the magnitudes of the induced stress and displacement of surrounding rock masses: a larger stress concentration and heterogeneous distribution were more likely to occur in rock masses with lower fracture intensity. While the dip angle and strike of fractures showed more impact on the distribution of displacement and failure modes of surrounding rock masses, especially for those on the roof and sidewall.
View
Deformation Mechanism and Control Technology of Surrounding Rock in the Deep-Buried Large-Span Chamber
Article
Full-text available
The selection of the support scheme for deep-buried and large-span chambers has been a severe problem in underground engineering. To further study the mechanical mechanism of large deformation, based on the repair engineering of the chambers of Pingdingshan No.6 mine in China, the field investigation, laboratory test, numerical simulation, and theoretical analysis were studied. The surrounding rock of the central substation chamber (CSC) and the main pumping chamber (MPC) were classified according to the rock mass rating (RMR) classification method, and the main factors affecting the stability of the surrounding rock of the chambers were revealed. A prediction model of mechanical parameters of the surrounding rock was established based on the Hoek-Brown failure criterion. Additionally, the prediction results were used in FLAC3D to further analyze the failure of the original support scheme, and the feasibility of the restoration plan was proposed. Six key points of support technology for this kind of chamber were put forward. Comprehensive support and repair scheme, including "bolt, metal mesh, shotcrete, grouting, anchor cable, and combined anchor cable,"was put forward. The engineering practice indicated that the deformation rate was less than 0.7 mm/d, which was beneficial to the long-term stability of CSC and MPC. The implementation of this restoration project can provide a reference for other similar projects.
View
Experimental and theoretical investigation on mechanisms performance of the rock-coal-bolt (RCB) composite system
Article
Full-text available
  • Aug 2020
Keywords: Thin coal seam Coal and rock roadway Bolt Tension-shear failure ''Rock-coal-bolt" composite system a b s t r a c t For coal mines, rock, coal, and rock bolt are the critical constituent materials for surrounding rock in the underground engineering. The stability of the ''rock-coal-bolt" (RCB) composite system is affected by the structure and fracture of the coal-rock mass. More rock bolts installed on the rock, more complex condition of the engineering stress environment will be (tensile-shear composite stress is principal). In this paper, experimental analysis and theoretical verification were performed on the RCB composite system with different angles. The results revealed that the failure of the rock-coal (RC) composite specimen was caused by tensile and shear cracks. After anchoring, the reinforcement body formed inside the composite system limits the area where the crack could occur in the specimen. Specifically, shearing damage occurred only around the bolt, and the stress-strain curve presented a better post-peak mechanical property. The mechanical mechanism of the bolt under the combined action of tension and shear stress was analyzed. Additionally, a rock-coal-bolt tensile-shear mechanical (RCBTSM) model was established. The relationship (similar to the exponential function) between the bolt tensile-shear stress and the angle was obtained. Moreover, the influences of the dilatancy angle and bolt diameter of the RCB composite system were also considered and analyzed. Most of the bolts are subjected to the tensile-shearing action in the post-peak stage. The implications of these results for engineering practice indicated that the bolts of the RCB composite system should be prevented from entering the limit shearing state early. Ó 2020 Published by Elsevier B.V. on behalf of China University of Mining & Technology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
View
Assessment of the Excavation Damaged Zones in the Surrounding Rock of an Underground Powerhouse under High In Situ Stress Using an Acoustic Velocity Detecting Method
Article
Full-text available
  • Jul 2020
Excavation damaged zones (EDZs) in deeply buried underground powerhouse have become major obstacles to design and support, which potentially threaten safety and stability and increase construction and support costs. In this study, investigations of the EDZs were performed by applying an acoustic velocity detecting method in Houziyan hydropower project, southwest of China. A total of 38 testing boreholes distributed in high sidewalls of the main powerhouse were carried out, and corresponding 153 curves were obtained and analyzed. Then, EDZs were divided into highly damaged zone (HDZ), slightly damaged zone (SDZ), and excavation influence zone (EIZ), respectively. Furthermore, we classified the wave velocity curves into four categories: type I, type II, type III, and type IV. EDZs were qualitatively assessed based on the curve categories; in addition, we used a qualitative assessment method, which mainly involved an index of damage degree named D. The assessment results show that HDZ, but not SDZ, was significantly asymmetrically distributed in the upstream (average depth of 4.1 m) and downstream (average depth of 7.5 m) high sidewalls; in partial areas, depth of HDZ exceeded the length of designed rock bolts, which indicates that rock bolts cannot restrain crack development and EDZs evolution. Generally, EDZs distribution was consistent with deformation and failure phenomena distribution; compared to the field failure phenomena, the assessment results were reliable and reasonable. Finally, EDZs formation mechanism was discussed, and it can be concluded that the relatively large intermediate principal stresses σ2 were a critical driving factor of the EDZs evolution.
View
Stability of Close Chambers Surrounding Rock in Deep and Comprehensive Control Technology
Article
Full-text available
  • Aug 2018
The purpose of this paper is to solve the problem that deep and close-distance cavern and roadway group were easily affected by the adjacent chamber or roadway excavation disturbance and low stability and significant deformation of surrounding rock occurred. The stability and control technology of surrounding rock in the main shaft and auxiliary shaft system has been analyzed by the adjacent chamber and roadway group of −850 m level in Qujiang Mine, China, as an engineering background. Firstly, the numerical calculation of the excavation chamber was, respectively, carried out in different ways with the propagation theory of the excavation disturbance wave. The results show that the interaction of adjacent chamber excavation was more intense. When excavated at the same time, there is a large increase in the movement of the sides and the roof-floor of the chamber and roadway. Then, the mechanism of interaction between low-high stress and excavation disturbance was considered, the corresponding control principles were provided, and a set of critical technologies and equipment were designed according to the deformation characteristics of the large deformation soft surrounding rock. Finally, the comprehensive control method was put forward with the water pump house as an example, that is, anchor, metal net, grouting, combined anchor cable and large-diameter anchor cable. And the related support parameters were determined by the internal damage of the surrounding rock chamber. The numerical simulation results show that the surrounding rock deformation of the chamber and roadway reduced with the revised support program, which the expansion of the rock mass loose circle prevented effectively. The site test shows that the convergence rate of surrounding rock with the improved support was less than 0.2 mm/d, and the rock deformation of chamber and roadway suppressed significantly.
View
A case study of mining-induced impacts on the stability of multi-tunnels with the backfill mining method and controlling strategies
Article
Full-text available
  • Mar 2018
  • ENVIRON EARTH SCI
Deep mining practices are jeopardized by the recurrent instability and failure of roadways/multi-tunnels. This paper describes a case study of the mining-induced impacts on the stability and control strategy of overlying multi-tunnels with backfill mining in the Ping Dingshan No. 10 Coal Mine in Henan Province, China. To reveal the dynamic impacts of coal mining on the stability of overlying multi-tunnels, particularly in the process of mining cycle and after the overlying strata long-term stability period, a 3D finite element model was applied to explore the effect of longwall panel width, advancing distance, and backfill material’s compaction ratio (BMCR) on the multi-tunnels’ deformation characteristics. The results obtained demonstrate that failure and deformation of the overlying multi-tunnels become more pronounced with the increased longwall panel width and advancing distance, as well as with BMCR reduction. The ranking of deformation degree in the overlying multi-tunnels is as follows: main haulage roadway > auxiliary haulage roadway > main inclined shaft > rock crosscut > auxiliary inclined shaft. Using a 2D physical simulation experiment, a comprehensive analysis method and engineering design concept for the stability control of overlying multi-tunnels with backfill mining are put forward based on further research of the deformation characteristics of multi-tunnels using caving and backfilling method. The results obtained are instrumental to the stability control of overlying tunnels in deep mining practices with similar conditions.
View
Combined Supporting Technology with Bolt-Grouting and Floor Pressure-Relief for Deep Chamber: An Underground Coal Mine Case Study
Article
Full-text available
  • Jan 2018
Based on the engineering geological conditions of the Number 2 chamber in the slope at Xinzhuang coal mine, which is located in the eastern part of Yongcheng City, Henan Province, China, the authors conducted a systematic research on the anchoring-grouting and the floor pressure-relief supporting technology by using theoretical analysis, numerical calculation and field industrial test. Results showed that: (1) the lithology of the surrounding rock was poor, and the stress and effective loading coefficient on the chamber surrounding rock were high due to the abutment pressure that was induced by the shaft protective pillar. Both of them resulted in the floor heave and the surrounding rock deformation damage of the chamber; (2) The numerical calculation showed that, after the floor pressure-relief slot was excavated in the head chamber, the vertical stress of the floor surrounding rock of chamber and the horizontal stress of the side surrounding rock were significantly reduced when compared with the stress before the pressure-relief, and the floor vertical displacement basically remained unchanged. So the floor pressure-relief slot could effectively control the chamber floor heave and was helpful for the long-Term stability of the chamber. After the severe deformation chamber was renovated by using a combined support with bolt-mesh-shotcreting and anchor cables, several other techniques were also applied to ensure the stability of the chamber. The floor pressure-relief slot was excavated, both the roof and the sides surrounding rock of chamber were grouted with grouting bolt, and both sides and the floor (including pressure-relief slot) of the chamber were grouted with anchor cable bundles. After implementation of above systematic techniques, the surrounding rock of chamber is in a stable state, which demonstrated that the field test is successful. The combined supporting technology with the anchoring-grouting and the floor pressure-relief has an important practical significance for the long-Term stability of the chamber to ensure the safe and efficient production of the mine.
View
Seismic Response Analysis of Concrete Lining Structure in Large Underground Powerhouse
Article
Full-text available
  • Jul 2017
  • MATH PROBL ENG
Based on the dynamic damage constitutive model of concrete material and seismic rock-lining structure interaction analysis method, the seismic response of lining structure in large underground powerhouse is studied in this paper. In order to describe strain rate dependence and fatigue damage of concrete material under cyclic loading, a dynamic constitutive model for concrete lining considering tension and shear anisotropic damage is presented, and the evolution equations of damage variables are derived. The proposed model is of simple form and can be programmed into finite element procedure easily. In order to describe seismic interaction characteristics of the surrounding rock and lining, an explicit dynamic contact analysis method considering bond and damage characteristics of contact face between the surrounding rock and lining is proposed, and this method can integrate directly without iteration. The proposed method is applied to seismic stability calculation of Yingxiuwan Underground Powerhouse, results reveal that the amplitude and duration of input seismic wave determine the damage degree of lining structure, the damage zone of lining structure is mainly distributed in its arch, and the contact face damage has great influence on the stability of the lining structure.
View
Stability analysis and failure mechanism of the steeply inclined bedded rock masses surrounding a large underground opening
Article
  • Jun 2018
  • TUNN UNDERGR SP TECH
The stability of high sidewalls of large-span underground openings is a crucial geological engineering issue when the steeply inclined rock strata form a small angle to the cavern axis. In this study, detailed field surveys, in-situ tests and numerical simulations were performed to investigate the stability and failure mechanism of bedded rock masses surrounding a large underground cavern at the Wudongde hydropower station in China. First, a 3D real time, movable microseismic (MS) monitoring system was installed to analyze the stability of the underground caverns. The micro-fracturing processes and potential failure mechanism of cataclinal layered rock masses were revealed by the spatial distribution evolution and seismic source parameters (i.e., S-wave to P-wave energy ratios, namely E s /E p) of the MS events. Then, an approach integrating the field surveys, MS monitoring and conventional measurements, is proposed for evaluating the cavern stability and identifying the high risk regions in the bedded rock masses during the staged excavations. Subsequently, discrete element method (DEM) was adopted to depict the progressive failure processes of the layered rock masses. The relationship between the failure in the upstream sidewall and the orientation and spacing of bedding planes was analysed. Abovementioned investigations allow us finally to conclude that the failure mechanism of the steeply cataclinal layered rock strata after cavern excavation is a combination of (1) the composite bending and sliding occurring in the lower part of the upstream sidewall with no supports, and (2) the opening and shear dislocation of bedding planes in the middle area. Timely supports for the rock strata at the toe of sidewall might be an effective way for preventing the occurrence of the studied failure.
View