scholarly journals Deformation Mechanism and Stability Control of Roadway Surrounding Rock with Compound Roof: Research and Applications

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1350 ◽  
Author(s):  
Yang Yu ◽  
Xiangyu Wang ◽  
Jianbiao Bai ◽  
Lianying Zhang ◽  
Hongchun Xia
Keyword(s):  
Bearing Capacity ◽  
Shear Failure ◽  
Early Stage ◽  
Tensile Force ◽  
Strong Support ◽  
Stability Control ◽  
Surrounding Rock ◽  
Guizhou Province ◽  
The Stability ◽  
Two Sides

In view of problems with roadways with a compound roof, such as the occurrence of instability in the roof strata, ease of separation of the layer caving, difficulty of maintenance, and poor safety, we established a mechanical calculation model of a roadway with compound roof using the elastic mechanics theory, taking the stability control of a roadway with compound roof at a coal mine in Guizhou Province, China as the research background, and based on the actual characteristics of the coal seam and the roof and floor slate. Expressions of the separation layer and instability limit load of compound roof were derived, and the calculation and verification were carried out in combination with the actual conditions. By means of numerical simulation, the distribution and evolution laws of stress, displacement and plastic zone of roadways with a compound roof were studied, and the deformation characteristics and instability mechanism of roadways with a compound roof were revealed: (1) in early stage deformation of roadway, the amount is large, the speed is fast, and the scale is wide; (2) compound roofs are vulnerable to abscission and instability, the bearing capacity of the two sides is low due to softness and cracking, the shear failure of side angles and vertex angles weakens the strength of surrounding rock, and the self-bearing capacity of surrounding rock is low; (3) the bolt and anchor bear relatively large tensile force, and the support structure is easy to be broken up. On this basis, the stability control principle of a roadway with compound roof tunnel was put forward: fast and timely support; high-strength bolt strong support; improving the stability of the roof and the bearing capacity of the two sides; restraining the shear failure of the key bearing parts such as the side angles and the bottom angles, and targeted stability control technology for roadways with a compound roof was developed. The field industrial test showed that the deformation of this roadway with a compound roof was effectively controlled and the overall stability of the roadway was effectively improved. The results of this study could provide useful reference for a roadway with a compound roof under similar conditions.

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.

Application of ABAQUS in Surrounding Rock Stability Analysis of Shallow Large Cross-Section Tunnel

2015 ◽  
Vol 777 ◽  
pp. 8-12 ◽  
Author(s):  
Lin Zhen Cai ◽  
Cheng Liang Zhang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Strong Support ◽  
Surrounding Rock ◽  
Tunnel Engineering ◽  
Tunnel Excavation ◽  
Rock Stability ◽  
Rock Bolting ◽  
Excavation Support ◽  
The Stability

HuJiaDi tunnel construction of Dai Gong highway is troublesome, the surrounding-rock mass give priority to full to strong weathering basalt, surrounding rock integrity is poor, weak self-stability of surrounding rock, and tunnel is prone to collapse. In order to reduce disturbance, taking advantage of the ability of rock mass, excavation adopt the method of "more steps, short footage and strong support". The excavation method using three steps excavation, The excavation footage is about 1.2 ~ 1.5 m; The surrounding rock bolting system still produce a large deformation after completion of the first support construction, it shows that the adopted support intensity cannot guarantee the stability of the tunnel engineering. Using ABAQUS to simulate tunnel excavation support, optimizing the support parameters of the tunnel, conducting comparative analysis with Monitoring and Measuring and numerical simulation results, it shows that the displacement - time curves have a certain consistency in numerical simulation of ABAQUS and Monitoring and Measuring.

scholarly journals Study of the Stability Control of the Rock Surrounding Double-Key Strata Recovery Roadways in Shallow Seams

2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Cheng Zhu ◽  
Yong Yuan ◽  
Zhongshun Chen ◽  
Zhiheng Liu ◽  
Chaofeng Yuan
Keyword(s):  
Engineering Application ◽  
Stability Control ◽  
Surrounding Rock ◽  
Control Effect ◽  
Pressure Relief ◽  
Support Design ◽  
Key Strata ◽  
Fracture Development ◽  
Surrounding Rock Control ◽  
The Stability

The stability control of the rock surrounding recovery roadways guarantees the safety of the extraction of equipment. Roof falling and support crushing are prone to occur in double-key strata (DKS) faces in shallow seams during the extraction of equipment. Therefore, this paper focuses on the stability control of the rock surrounding DKS recovery roadways by combining field observations, theoretical analysis, and numerical simulations. First, pressure relief technology, which can effectively release the accumulated rock pressure in the roof, is introduced according to the periodic weighting characteristics of DKS roofs. A reasonable application scope and the applicable conditions for pressure relief technology are given. Considering the influence of the eroded area on the roof structure, two roof mechanics models of DKS are established. The calculation results show that the yield load of the support in the eroded area is low. A scheme for strengthening the support with individual hydraulic props is proposed, and then, the support design of the recovery roadway is improved based on the time effects of fracture development. The width of the recovery roadway and supporting parameters is redesigned according to engineering experience. Finally, constitutive models of the support and compacted rock mass in the gob are developed with FLAC3D software to simulate the failure characteristics of the surrounding rock during pressure relief and equipment extraction. The surrounding rock control effects of two support designs and three extraction schemes are comprehensively evaluated. The results show that the surrounding rock control effect of Scheme 1, which combines improved support design and the bidirectional extraction of equipment, is the best. Engineering application results show that Scheme 1 realizes the safe extraction of equipment. The research results can provide a reference and experience for use in the stability control of rock surrounding recovery roadways in shallow seams.

scholarly journals Stability Analysis of Shallow and Bias Loess Tunnel Based on Finite Difference Method

2019 ◽  
Vol 131 ◽  
pp. 01027
Author(s):  
Li Yongbing ◽  
Binglei Li ◽  
Guanyu Hua ◽  
Xinran Jia ◽  
Yanqiao Chen ◽  
...  
Keyword(s):  
Finite Difference ◽  
Shear Failure ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Failure Zone ◽  
Tunnel Face ◽  
Whole Process ◽  
The Earth ◽  
Practical Engineering ◽  
The Stability

Based on the Mohr-Coulomb elastic-plastic model and the practical engineering background of Mopanshan tunnel, this paper applies the finite-difference software FLAC3D to simulate and analyse the whole process of loess tunnel construction. Then, it analyses the stability of the surrounding rock and sup-port structure after partial excavation of the loess tunnel under the shallow burying and unsymmetrical load-ing condition. The study showed that in the absence of support, the shear failure occurred to the top/upper pilot tunnel of the tunnel face, the failure zone under tensile stress happened to the shallow soil of the earth surface, and the soil of tunnel face appeared to be damaged. Finally, according to the analysis results, a rea-sonable construction method suitable for the shallow and bias loess tunnel is determined.

Research on Loose Circle Test of Deep Broken Roadway

2014 ◽  
Vol 638-640 ◽  
pp. 904-907 ◽  
Author(s):  
Feng Zhan Cui ◽  
Hua Jun Xue ◽  
Tian Yu He ◽  
Tao Tao Li ◽  
Jin Jing Zuo ◽  
...  
Keyword(s):  
Soft Rock ◽  
Surrounding Rock ◽  
Sonic Method ◽  
Single Hole ◽  
Deep Well ◽  
The Stability ◽  
Two Sides

To control the stability of deep well broken surrounding rock, single-hole sonic method is used to test the loose circle of-1180 east-rock main roadway and its damage range. The study indicates the loose circle is about 1.8 ~ 2.2 m, which is typical large loose circle. And its button is slightly larger than two sides’, right side slightly larger than left. The roadway rock has some engineering features of soft rock. The broken and expand deformation of loose circle does large, difficult to support. Combined support is usually used in this rock condition.

scholarly journals Supporting Forces and Stability of Snow-Slab Avalanches: A Parameter Study

1989 ◽  
Vol 13 ◽  
pp. 140-145 ◽  
Author(s):  
Bernhard Lackinger
Keyword(s):  
Shear Force ◽  
Shear Failure ◽  
Tensile Force ◽  
Normal Component ◽  
Compressive Force ◽  
Stability Index ◽  
Parameter Study ◽  
Shear Surface ◽  
The Stability ◽  
Low Shear

The fracture of a slab avalanche is a multi-phase and progressive process. The different kinds of fracture and possible scenarios of avalanche release in the form of a zip effect are shown. In the course of investigations, most importance has so far been attached to shear failure along the sliding surface. Various cases of load and their effects on the stresses, on the changes of strength, and on the stability of the inclined snow-pack are discussed. The usual simple model of the shear-stability index is unsatisfactory. The present paper deals with the complex interaction of all supporting forces of a snow slab by means of simplified geotechnical considerations. For this purpose, the acting and reacting forces of a “standard avalanche” (i.e. dead load with driving and normal component, shear force, tensile force, compressive force, and flank force) are estimated from published boundary values. Using different combinations (e.g. hard slab with high circumferential forces on a weak shear surface with low shear force), it can be shown that suspension at the crown and lower and lateral support are of great importance. This applies especially to cases with low shear forces and, consequently, with low overall stability. Despite the fact that the circumferential area of the model avalanche is only 6% of the area of the shear surface, the circumferential force in this case is more than 150% of the shear force. In a parameter study with different avalanche sizes, these results are generalized and confirmed. For the assumed strength limits, critical areas and depths of possible slab avalanches can be derived. Although the supporting shear force is the major contributor to stability, particularly with larger slabs, it can be seen from the investigations that the redistributions of stress and spatial supports and suspensions of the whole slab avalanche must not be neglected in stability analyses.

scholarly journals Failure behavior of the surrounding rock of jointed rock masses in a gold mine under impact disturbance

2021 ◽  
Author(s):  
Peng Li ◽  
Yunquan Wu ◽  
Meifeng Cai
Keyword(s):  
Stress Wave ◽  
Shear Failure ◽  
Jointed Rock ◽  
Surrounding Rock ◽  
Tensile Failure ◽  
Tensile Shear ◽  
Underground Engineering ◽  
Impact Stress ◽  
The Stability ◽  
The Impact

Abstract The impact disturbance has an important influence on the safety of underground engineering openings. In this paper, based on the in-situ stress measurement and structural plane investigation, the model of jointed rock roadway was established using the discrete element method (3DEC) to study the instability and failure characteristic of roadway surrounding rock with dominant joint planes under impact disturbance and to further analyze the influence of different buried depths, impact stress wave peaks, and stress wave delays on the stability of the surrounding rock. The results show that the stability of the surrounding rock is poor, and the whole convergence deformation of the surrounding rock occurs under the impact stress wave. There are three failure modes in the surrounding rock: tensile-shear failure, tensile failure, and shear failure. Tensile-shear failure mainly occurs in a small range close to the roof and floor of the roadway and the free surfaces of the two sides, and tensile failure occurs locally, while shear failure mainly occurs along the joint plane outside this range. Moreover, the greater the buried depth and stress wave peak value, the more serious the deformation of the surrounding rock. With the increase of stress wave delay, the deformation of the surrounding rock shows complex characteristics. In addition, the impact failure mechanism of the surrounding rock in jointed rock masses was discussed. The research results have important guiding significance for the prevention and control of underground engineering cavern disasters.

scholarly journals Stability Analysis of Surrounding Rock of Large Section Ultradeep Shaft Wall

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Cheng Li ◽  
Wang Chunlong ◽  
Wang Xi ◽  
Chen Kexu
Keyword(s):  
Control Method ◽  
Stress Test ◽  
Stability Control ◽  
Surrounding Rock ◽  
Main Shaft ◽  
Large Section ◽  
Masonry Construction ◽  
Temporary Support ◽  
The Stability ◽  
Shaft Wall

In order to study the stability of deep surrounding rock during the excavation of new main shaft in Xincheng gold mine, a construction method suitable for large section ultradeep shaft is proposed. A series of analyses were carried out in this study, including the in situ stress test, stress response of surrounding rock disturbance, deformation and failure characteristics, and numerical simulation. Based on the above analysis, the stability control method of surrounding rock in the process of deep excavation of the new main shaft is proposed. The results show that (1) the maximum principal stress of deep surrounding rock of new main shaft is horizontal stress, and the surrounding rock of the shaft has strong rock burst tendency after excavation; (2) the influence range of the deep shaft excavation disturbance is 6.4 times the shaft radius, in which the temporary support should be strengthened to avoid the influence of excavation disturbance on the stability of shaft wall rock; (3) the failure shape of surrounding rock of the deep shaft excavation was “ear” failure, and the failure depth was not more than 2.5 m; (4) after replacing the original “one-excavation and one-masonry” construction with “three-excavation and one-masonry” construction, the temporary support span of the main shaft was adjusted to 12 m, which can make the subsequent concrete shaft wall in the state of “no pressure bearing or slow low pressure bearing,” and the lining compressive safety coefficient was increased to 1.98, which meets the safety requirements.

The Stability Control Technology of Crosscut while Mining without Coal Pillar in Steep Seam

2011 ◽  
Vol 90-93 ◽  
pp. 2073-2079
Author(s):  
Yu Feng Wang ◽  
Zhi Qiang Liu ◽  
Bin Song Jiang
Keyword(s):  
Support System ◽  
Coal Pillar ◽  
Stability Control ◽  
Surrounding Rock ◽  
Steep Seam ◽  
Floor Rock ◽  
Long Term Stability ◽  
Rock Collapse ◽  
The Stability

In order to improve the mining benefit of coal resources, Chang Gouyu Coal Mine carried out the technology of mining without coal pillar in steep seam. The key of the technology was to ensure a long-term stability of the cross-entry roadway across the seam. Through the analysis of the nature of steep seam roof and floor rock, and based on the stability analysis and loose circle measured of surrounding rock of crosscut roadway, we brought forward adopting shotcrete rockbolt mesh and U-shaped steel complex support structure system. This complex support system could flex lengthways and compress in radial direction. The entirety integrated with the surrounding rock, and they formed into a whole. Application of the complex support system could effectively control the deformation of the surrounding rock collapse, and maintain the stability of the crosscut.

Monitoring and Reinforcement Technology of Passing Weak and Broken Rock Strata for Tunnel Boring Machine

2012 ◽  
Vol 204-208 ◽  
pp. 2819-2823
Author(s):  
Tao Li ◽  
Kai Bin Liu ◽  
Wei Hong Yang ◽  
Bo Liu ◽  
Ying Chao Liu
Keyword(s):  
Tunnel Boring Machine ◽  
Stability Control ◽  
Surrounding Rock ◽  
Tunnel Boring ◽  
Rock Stability ◽  
Tunnel Convergence ◽  
Geological Conditions ◽  
The Stability ◽  
Large Tunnel ◽  
Rock Strata

The stability control of surrounding rock is a relatively important problem in tunnel boring machine (TBM) construction. The tunnel convergence deformation value was monitored in field while TBM passing weak and broken section of hydraulic tunnel. The correlation between tunnel convergence and surrounding rock stability is analyzed. The monitoring results show that: the characteristic of weak and broken Strata is closely correlated with some geological conditions, such as fault development, intrusive contact of orthophyre and lamprophyre veins. These supporting measures can well ensure the stability of surrounding rock in weak and broken section, such as sealing the inverted arch by using concrete of C25,reinforcing the inverted arch by steel arch of I10 and anchor construction in the roof. There is great difference between the properties of the weak and broken rocks on both sides, which is the main reason of the large tunnel convergence deformation. The monitoring results can provide reference for similar engineering in the future.

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