Roadway Displacement Research Articles

Characteristics of deformation and damage of surrounding rock along the top roadway in the working face of an isolated island and its evolution law

This study investigates the deformation and damage characteristics of the surrounding rock along the top return mining roadway of an isolated island working face at different stages and reveals its damage mechanism and evolution law. Utilizing a mine in Yangquan City, Shanxi Province, China, as the engineering background, this research employs FLAC 3D numerical simulation and on-site measurements. The findings suggest that the evolution of the plastic zone along the top roadway of the 15,106 island face is largely similar during both the excavation and mining periods. The plastic zones on either side of the roadway are expanding asymmetrically and gradually merging into the plastic zone of the coal pillar. In the destructive stage, the sub-gangs of the roadway are penetrated, indicating the progression into the plastic zone. The investigation points to extensive damage on the larger side of the roadway, the development of fissures, and the significant depth of damage as primary causes of roadway deformation. Moreover, the extent of the plastic zones on both sides of the roadway correlates positively with their relative distance. Continuous monitoring reveals an ongoing increase in roadway displacement, consistent with general observations in coal mining. The results provide valuable insights for optimizing support structures in similar mining environments.

Experimental and numerical investigation on failure characteristics and mechanism of coal with different water contents

Water injection, as a widely used technique to prevent coal burst, can restrain the fractured coal seam and released the energy storage. In this study, laboratory tests were firstly carried out on standard coal specimens with five different water contents (i.e., 0%, 0.6%, 1.08%, 1.5%, 2.0%, and 2.3%). The failure mode, fragment size, and energy distribution characteristics of coal specimens were investigated. Experimental results show that strength, elastic strain energy, dissipated energy, brittleness index, as well as impact energy index decrease with increasing water content. Besides, the failure mode transitions gradually from splitting ejection to tensile-shear mixed failure mode as water content increases, and average fragment size shows positively related to water content. Moreover, scanning electron microscope tests results indicate that water in coal sample mainly causes the mineral softening and defects increase. Furthermore, a numerical model containing roadway excavation was established considering the water on coal burst prevention. Modelling results revealed that water injection can reduce degree of coal burst and ejection velocity of coal blocks, while it will raise up the depth of crack zone and surface displacement of roadway. Combined with laboratory tests and numerical results, the micro mechanism, energy mechanism, and engineering significance of water injection on coal burst prevention were finally analyzed.

Application and Principle of Bolt-Mesh-Cable Control Technology in Extremely Soft Coal Seam Roadway

The extremely soft coal seam roadway has the problems of low surrounding rock strength and difficult support. Based on the engineering background of the mining roadway in the extremely soft coal seam of the Quandian coal mine, this paper adopts the research method combining numerical simulation and field measurement. The stress field, displacement field, support force, and loading arch structure characteristics of roadway surrounding rock under bolt-mesh-cable support and existing shed-cable support are compared, and the control principle of bolt-mesh-cable in extremely soft coal seam roadway is expounded. Our study indicated that compared with nonsupport and shed-cable support, the pressure stress range of the surrounding rock in extremely soft coal seam increases, and the stress gradient decreases when bolt-mesh-cable support is used. The roadway displacement and displacement difference decrease. The components of the support achieve stress coordination. The thickness of the loading arch formed in the surrounding rock is large, and the compressive stress in the arch is evenly distributed. The bolt-mesh-cable significantly improves the stress environment and the stability of the roadway. The field practice shows that the roadway deformation is small after the bolt-mesh-cable support is adopted, and the roadway section during excavation and mining meets the requirements of safety production.

Discontinuous Deformation Characteristics of Deep Buried Roadway Roofs and Linkage Control of Thick Layer Cross-Boundary Anchorage: A Case Study

After deep mining, the discontinuous deformation characteristics of roadway roofs become more and more obvious, resulting in the emergence of separation fractures in the rock mass, which seriously affects the stability of the roof rock mass. By taking the air return roadway 21204 (ARR 21204) in Hulusu Coal Mine as the engineering background, this article reveals the discontinuous deformation characteristics of deep buried roadway roofs through field research, numerical simulation, theoretical analysis and engineering practice. After roadway excavation, the rock masses in different shallow roof horizons show different degrees of stress unloading, resulting in the occurrence of discontinuous deformation phenomena in rock masses. With the rise of the roof rock horizon, the degree of discontinuous deformation fades away until a continuous deformation zone with small deformation and stable rock strata appears. In addition, with the increase in the roadway buried depth, the extent of the discontinuous deformation of the roof and its extended range tend to increase. In view of the discontinuous deformation control of the roof, the technology of linkage control of thick layer cross-boundary anchorage is proposed. By establishing the thick anchorage ring of the roof, the bolts cross the discontinuous deformation zone to support the stable rock strata in the deep continuous deformation zone, thereby realizing the linkage control of the large and small displacement of the rock masses in these two zones and limiting the progressive damage of the roof rock mass from shallow to deep. The industrial test shows that the scope of the separation fracture zone on the roof is controlled at the shallow stratum of 0.85 m due to the great decrease in the surface displacement of roadway, which effectively restricts the progressive upward extension of the discontinuous deformation zone of the roof. The research results can provide references for the safe and efficient control of roadway roofs under deep mining conditions.

Research on orthogonal experimental design technology based on anchor mesh cable coupling support

In view of the difficulty in supporting the return air gateway under the goaf of the close coal seam in Xihe Coal Mine, in order to improve the stability of the roadway of the close coal seam group and the supporting effect of the roadway, the orthogonal test method is adopted. Based on seven main influencing factors, such as the length of the anchor bolt, three common variables are set for each factor, and the FLAC3D numerical simulation software is used to simulate and analyze 18 groups of orthogonal tests to obtain the best optimization scheme. Then, the deformation of surrounding rock and the range of shaping zone are compared before and after optimization. Compared with the original support scheme, the optimized support scheme reduces the roadway displacement, reduces the stress release area, improves the bearing capacity of surrounding rock, effectively solves the serious problem of surrounding rock deformation in Xihe Coal Mine, and provides theoretical and technical support for roadway deformation control.

Mechanism of Roof Deformation and Support Optimization of Deeply Buried Roadway under Mining Conditions

Large deformations in local areas during service in a mine roadway are prone to roofing hazards, seriously threatening people’s lives and urgently needing to be addressed by means of support optimization. Traditional methods of studying the stability of the roadway roof are mainly based on the theory of the surrounding rock loosening circle, but few studies analyze the stability of roadway roofs around the failure distribution and expansion of weak interlayers. Therefore, the relationship between the deformation characteristics of the tunnel envelope and the thickness of the soft and weak interlayer and the underlying hard rock layer was investigated using a comprehensive research method such as theoretical analysis, numerical simulation, and field monitoring. The results show that the form of roadway roof failure is determined by weak interlayer thickness. For a mining-disturbed roadway, if the weak interlayer thickness remains unchanged, as the underlying hard strata thickness increases, the existence of a more integral hard stratum cannot prevent plastic zones from forming in the weak interlayer but can prevent them from developing in the key layer 1. If the underlying hard strata thickness remains unchanged, the smaller the weak interlayer thickness, the smaller the area of plastic zone failure in the roadway roof. After the deformation characteristics of the roadway containing the weak interlayer were clarified, according to its characteristics, the support optimization method of increasing the length of anchor bolt and anchor cable is proposed. The displacement of the roadway roof was reduced by 35% after verification by numerical simulation. After applying the support optimization method on site, the roadway displacement basically stabilized after 40 days, with the roof slab sinkage, two gang convergence and bottom bulge reaching 53 mm, 42 mm and 39 mm, respectively. The overall deformation of the roadway was small, effectively controlling the surrounding rock deformation and reducing economic losses for the mine.

A Unified Solution for Surrounding Rock of Roadway Considering Seepage, Dilatancy, Strain-Softening and Intermediate Principal Stress

The analytic solution for surrounding rock of roadway is of significance for stability analysis and roadway support. However, analytical solution for surrounding rock of roadway which took influences of water seepage, strain softening, dilatancy and intermediate principal stress all into account did not receive much reporting. To promote research in this aspect, a mechanical model simultaneously considering water seepage, strain softening, rock dilatancy, and intermediate principal stress was established based on porous elastoplastic mechanics, and then unified analytical solution for surrounding rock of roadway was obtained. Based on an example, influences of water seepage, strain softening, rock dilatancy, residual cohesion and intermediate principal stress on surrounding rock of roadway were thoroughly investigated using single factor analysis. The obtained results are as follows: radii of plastic zones and surface displacement of roadway would increase exponentially with water pressure increasing and their magnitudes are greater than corresponding values without water seepage considered; with softening modulus increasing, peak circumferential stress location would slightly shift to deeper surrounding rock, while broken zone radius and surface displacement of roadway would increase in a decay velocity; rock dilatancy has little effect on peak circumferential stress and plastic softening zone radius, while broken zone radius and surface displacement of roadway increase linearly with dilatancy coefficient α1 increasing indicating their magnitudes are overestimated if associated flow rule is adopted; with weighted coefficient increasing, stress components in plastic zones at the same distance from roadway center would increase, while radii of two plastic zones and surface displacement of roadway are reduced, i.e., self-bearing capacity of rock is enhanced considering intermediate principal stress effect compared to Mohr–Coulomb criterion; with residual cohesion increasing, peak circumferential stress remains unchanged, while stress components in plastic zones at the same distance from roadway center would increase and radii of two plastic zones decrease significantly. The above results implicated that water seepage effect should be carefully considered for roadway stability under groundwater environment; strain-softening and flow rule of rock should be reasonably analyzed and chosen to accurately predict surface displacement and broken zone radius of roadway; rock bolt length should be increased with softening modulus increasing, while it can be decreased with intermediate principal stress effect considered; grouting measure is an effective measure to improve roadway stability. In short, the research provides a theoretical basis and some practical engineering implication for roadway support.

Influence of Yield Pillar Width on Coal Mine Roadway Stability in Western China: A Case Study

Roadway excavation technology in underground coal mines has an important impact on mining efficiency and production safety. High-efficiency and rapid excavation of underground roadways in coal mines are important means to improve the production efficiency of coal mines. To tackle the problems of instability of roadway and support difficulties, the tail entry of panel 3105 in Mataihao Mine was used as the case study. The methods of underground investigation, theoretical analysis, and FLAC3D numerical simulation were used to analyze the stability of the surrounding rock under different yield pillar widths. Through the stress field, displacement field, and plastic zone of roadway surrounding rock, the stability of the rock surrounding the roadway under different yield pillar widths (4 m, 6 m, and 8 m) was analyzed. The results show that, with the increase in the yield pillar width, the plastic zone failure and displacement of the roadway surrounding rock are mainly manifested in the narrow pillar rib, seam rib, roof, and floor. The plastic zone distribution changes slightly; the roadway displacement exhibits basic symmetry. The vertical stress and the displacement of the two sides increase with the increase in the yield pillar width, and the roof displacement and the ratio of tensile failure of the surrounding rock decrease with the increase in the yield pillar width. According to the dynamic evolution law of the rock surrounding the roadway along the goaf side, the effect of the yield pillar size is revealed, and a reasonable yield pillar width is determined. When the yield pillar width is 6 m, the plastic zone failure of the surrounding rock and the displacement of the two sides of the roof are the most balanced among the three schemes. This provides a reference for the selection of the narrow yield pillar size in coal mines under the same geological conditions.

Optimal Support Solution for a Soft Rock Roadway Based on the Drucker–Prager Yield Criteria

Through theoretical calculation, the stress and deformation of surrounding rock can be analyzed, providing guidance for the support design and optimization of soft rock roadways. In this paper, theoretical solutions for both the optimal support pressure and the allowable maximum displacement of surrounding rock are derived from the Drucker–Prager (DP) yield criteria and the steady creep criterion expressed by the third invariant of deviator stress. The DP criterion with different parameters is compared and analyzed with an engineering example. Then, based on the calculation results the effects of long-term strength, cohesion, and internal friction angle of soft rock on the maximum plastic zone radius and allowable maximum displacement of roadway are discussed. The results show that the optimal support solution of soft rock roadways based on the DP criteria can not only reasonably reflect the intermediate principal stress but can also be used to compare and discuss the influence of different DP criteria on the calculation results. The higher the long-term strength of the rock surrounding a roadway is, the smaller the optimal support force is and the larger the allowable maximum displacement is. When the calculated long-term strength of soft rock can ensure that the deformation of the roadway does not exceed the allowable maximum displacement, the roadway can maintain long-term stability without support. With an increase in the cohesion or internal friction angle of soft rock, the radius of the plastic zone decreases gradually and the allowable maximum displacement is reduced by degrees. The use of grouting and other means to improve the strength of surrounding rock can effectively reduce the roadway deformation and save support costs. This new theoretical solution can consider different intermediate principal stress effects and different DP strength criteria, enabling the parameters to become easier to determine. It has a wider range of applications, and the calculation results better demonstrate the strength potential of the surrounding rock.

Study on Optimization of Shallow Section Coal Pillar Width of Gently Inclined Medium-Thickness Coal Seam

This paper takes a coal mine gently inclined medium-thickness coal seam as the object. Firstly, the principal stress characteristics and displacement characteristics of roadway surrounding rocks after roadway driving along goaf under section columns with different breadthes were analyzed by simulation method, and the roadway stability was evaluated to determine the reasonable breadth. The results show that when the breadth of column is 4 m, the Mohr stress circle of the pillar intersects the strength envelope and the roof and side displacement of roadway are significant; when the breadth is 6 m, the Mohr stress circle on both flanks of the pillar intersects at the strength envelope and the roof and side displacement of roadway are significant; when the breadth is 8-12 m, the Mohr stress circle of surrounding rock is separated from the strength envelope and the surrounding rock displacement meets the production needs. Therefore, it is in a stable state. 8-12 m is the reasonable width range of coal pillar. Secondly, through the actual project verification, the 8 m wide coal pillar is the most reasonable for the shallow part of the gently inclined medium-thickness coal seam.

Research on Deformation Characteristics and Control Technology of Soft Rock Roadway under Dynamic Disturbance

In the mining process of an underground coal mine, the dynamic load often causes great damage to the roadway and affects the normal mining of coal mine. In this paper, the deformation of surrounding rocks under static load and different disturbance intensities is studied by numerical simulation. The results show that under the same static load condition, the greater the dynamic load strength is, the more obvious the roadway roof displacement subsidence is. With the increase in dynamic load propagation distance, the amplitude of the dynamic load waveform decreases gradually. Under the same disturbance load intensity, the variation of roadway displacement with different disturbance load frequencies is studied. According to the influence of dynamic load on the deformation of the roadway, a combined support plan of shotcrete anchor net and reinforcement anchor cable is proposed. Finally, the rationality of the optimized support scheme is verified by numerical simulation and field results. The results show that the combined support scheme can effectively increase the strength of the broken soft rock and reduce the deformation of the surrounding rock. At the same time, it releases the expansion energy generated by the mutual compression and deformation of the rock layers, effectively maintaining the long-term stability of the roadway.

Application research on hydraulic fracturing of cross-layer drilling in Sijiazhuang Coal Mine

The No.15 coal seam of Sijiazhuang Coal Mine belongs to high gas and low permeability coal seam. Hydraulic fracturing, as a technical measure for outburst prevention, is more and more widely used in high gas outburst mines. The influence of hydraulic fracturing high-pressure water on stress and displacement of roadway is analyzed, and the feasibility of hydraulic fracturing is verified. The industrial test of hydraulic fracturing through layers was carried out and the effect of gas extraction was investigated. The average concentration and pure volume of gas extraction unit in the fracturing area were 3.1 times and 5.7 times of those in the non fracturing area, respectively, which verified the permeability increasing effect of hydraulic fracturing measures. Through fracturing test, the extraction effect has been significantly improved. This paper provides important theoretical support and practical basis for hydraulic fracturing under similar conditions.

Study on Optimization of Crossheading Support and Lateral Stress Evolution Law with Shallow Buried Soft Rock

In a shallow-buried coal mine, the original support scheme of large crossheading has features of excessive strength and resource waste. Firstly, various optimization schemes are obtained through permutation and combination, and verified through numerical simulation. Additionally, under the premise of ensuring safety and economy, the optimal scheme is determined as A3B3: For the roof support, there are 5 rockbolts in each row, with spacing of 1100 × 1000 mm. Row-spacing between anchor cables is 2200 × 2000 mm. There is 1 bolt per row for each sidewall, 1050 mm from the roof and with the spacing of 1400 mm. In order to study the evolution of lateral abutment pressure during the dynamic load stage, FLAC3D was applied. The plastic zone range from coal seam excavation to model equilibrium is analyzed. Finally, the rationality of the design is verified by analyzing the observed of borehole television and roadway displacement.

Deformation and failure laws of roadway surrounding rock and support optimization during shallow-buried multi-seam mining

Gobs and coal pillars left in the upper coal seam exploitation bring a series of changes to the surrounding rock structures and stress environment of the roadway in the lower coal seams, which leads to difficulties in roadway maintenance. Firstly, the deformation and failure laws of roadway surrounding rock during shallow-buried multi-seam mining are studied using UDEC simulation. The results show that the vertical-stress concentration of the roadway under the coal pillar is stronger than that under the gobs and solid coal. The roadway displacement mainly undergoes three stages, i.e. severe deformation, slow deformation and deformation stabilization. Each of the three stages has the critical deformation value. The roadway displacement under the coal pillar also is larger than that under the gobs and solid coal. Then, allowing for its location, the roadway can be divided into three subareas, including below solid coal, below gobs and below coal pillars. The roadway below gobs consist of two kinds of subareas, i.e. the interlayer spacing is 3.2–4 m and the other is larger than 4 m. The support schemes corresponding to the four subareas are put forward. Finally, these proposed support schemes are used in the subareas of No. 20314 auxiliary haulage roadway. The field monitoring results show that the roadway displacement is small and bolt (cable) forces are stable, and the support effect is excellent. This study can provide a reference for roadway support in shallow-buried coal seams under similar geological conditions.

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

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.

Investigation on the evolution and control of surrounding rock fracture under different supporting conditions in deep roadway during excavation period

This paper presents an investigation of fracture evolution of surrounding rock with different supporting conditions during excavation period in Hulusu coal mine, Inner Mongolia, China. Fractures of surrounding rock were measured by borehole images obtained with a digital panoramic borehole camera, and surface displacement of roadway was measured using the intersection point method. Based on the rock properties, original support method and constructional process of bolter miner, a simple and fast support system was proposed, which realized the complete parallel operation between bolt support and coal cutting. According to the data obtained from field monitoring and construction situation, the array pitch was extended from 1.0 m to 1.5 m gradually. Field measurements indicated that the overall effect of roadway under new support was more satisfactory than under original support, with no exception in all the five test stages. When the array pitch extended up to 1.5 m, the roof and rib convergence were 11 mm and 16 mm, a reduction of 66.7% and 57.9%, respectively. Under new supporting condition, fractures were distributed only within the bolt anchorage zone and both the number and opening of fractures were small. By contrast, under original supporting condition, fractures were distributed both in and out of the bolt anchorage zone. New support can make full use of deep strata by constructing thick anchorage rock beam, and large displacement of shallow strata can be inhibited through small displacement of deep strata. The realization of co-movement between large-small displacements ensures the safety control of roadway. New support can greatly improve support efficiency, providing a solution to the imbalance between excavation speed and production needs widely existing in coal mines producing 10 million tons a year. New support has already been successful applied in another roadway with top coal in Hulusu coal mine.

Study on Optimization of Roadway Position in Pre-mining Upper Layered Concave–Convex Coal Body

Reasonable roadway layout is of great significance for mine safety and high efficiency production. The “concave–convex” coal body formed by pre-mining upper strip mining in Jinqiao Coal Mine, in order to recover the remaining coal resources, the selection of reasonable roadway location has become the first problem to be solved. In this paper, by means of theoretical calculation and numerical simulation, the failure range of plastic zone of floor and stress distribution law after upper layer mining are studied. At the same time, the stress distribution and displacement of roadway with different coal pillar width are analyzed. The results show that: After the upper layer mining, the failure depth of the floor is 6.9 m, the “ voussoir beam” is formed at the edge of the goaf, the stress distribution in the coal pillar presents “double hump”, the roadway is arranged in the middle of the coal pillar, the stress concentration is the smallest, and the deformation of the roadway is the smallest. Therefore, the optimum layout position of the mining roadway is determined. Through the field monitoring, the roadway deformation within the allowable range, the desired purpose has been achieved. It can provide theoretical support for the selection of roadway location under similar conditions.

Analysis and monitoring of roadway deformation mechanisms in nickel mine, China

SummaryDeformation of surrounding rock of roadway in deep is an important issue for mining engineering. We did some investigations and monitoring works in Jinchuan Mine 2. In this paper, based on field investigation, roadway deformation was summarized three features: horizontal displacement of roadway is larger than vertical displacement; roadway deformation has time effect, and also has large convergence. The monitoring data showed that roadway deformation was influenced by mining operation, but the scope of mining influence is not large. Roof conditions have effect to deformed process of roadway. Three mechanisms of surrounding rock deformation were analyzed that are rock dilatancy mechanism; shearing wedges block slide mechanism; springback of surrounding rock mechanism. We compared these mechanisms to field rock failure.

Mining-induced stress distribution of the working face in a kilometer-deep coal mine—a case study in Tangshan coal mine

Because of the large original stress in deep mining, compared with shallow mining, it is more likely to cause the occurrence of dynamic disasters such as rock burst, coal and gas outburst by the mining-induced stress concentration. Therefore, it is of great significance to master mining-induced stress distribution in deep mining. Mining-induced stress distribution of the working face in a kilometer-deep coal mine has been studied in this paper. The paper presents a study incorporating field monitoring, numerical simulation and theoretical analysis. Through analysis of field measured results, the following conclusions are made. For the area of the working face whose upward side and lateral direction are both unexcavated, the influence scope of advancing abutment pressure is 73 m; for another area whose upward side and lateral direction are both excavated, the influence scope is 64 m; for the area whose upward side is excavated and whose lateral direction is unexcavated, the influence scope is 31 m. Meanwhile, according to roadway displacement deformation monitoring, the influence scopes of advancing abutment pressure of the above areas are respectively 70 m, 68 m and 45 m, consistent with field stress monitoring results. In addition, the results obtained by FLAC3D numerical simulation fits relatively well with field measured results. In the end, combining with theoretical analysis, it determines the high stress concentration zone of the working face, provides a decision-making basis for taking advanced pressure relief measures and offers a reference for the safe mining of both follow-up working faces and other working faces with similar conditions.

Improvement of analytical factor of safety estimation of falling failure mode in roof wedge stability

This paper presents an investigation of fracture evolution of surrounding rock with different supporting conditions during excavation period in Hulusu coal mine, Inner Mongolia, China. Fractures of surrounding rock were measured by borehole images obtained with a digital panoramic borehole camera, and surface displacement of roadway was measured using the intersection point method. Based on the rock properties, original support method and constructional process of bolter miner, a simple and fast support system was proposed, which realized the complete parallel operation between bolt support and coal cutting. According to the data obtained from field monitoring and construction situation, the array pitch was extended from 1.0 m to 1.5 m gradually. Field measurements indicated that the overall effect of roadway under new support was more satisfactory than under original support, with no exception in all the five test stages. When the array pitch extended up to 1.5 m, the roof and rib convergence were 11 mm and 16 mm, a reduction of 66.7% and 57.9%, respectively. Under new supporting condition, fractures were distributed only within the bolt anchorage zone and both the number and opening of fractures were small. By contrast, under original supporting condition, fractures were distributed both in and out of the bolt anchorage zone. New support can make full use of deep strata by constructing thick anchorage rock beam, and large displacement of shallow strata can be inhibited through small displacement of deep strata. The realization of co-movement between large-small displacements ensures the safety control of roadway. New support can greatly improve support efficiency, providing a solution to the imbalance between excavation speed and production needs widely existing in coal mines producing 10 million tons a year. New support has already been successful applied in another roadway with top coal in Hulusu coal mine.