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To prevent the early breakage of anchor cables under shear loads in support engineering, a combined structure of Anchor Cable with C-shaped Tube (ACC) has been proposed. The shear resistance enhancement mechanism of this structure and the mechanisms of various influencing factors have yet to be fully revealed. A refined nonlinear finite element model of ACC was original established using ABAQUS software, taking into account the actual structure of the steel strands and the interactions, such as contact and failure between the various components. Various anchor cable pretension forces and block strengths were set to investigate their effects on the shear mechanical response of ACC. The results successfully demonstrated a high correlation between peak shear load and pretension force. The results demonstrate that an increase in pretension force reduces the ACC's peak shear load and break displacement. Additionally, the structure exhibited higher flexural stiffness, the block strength was mobilized earlier, and the block failed locally more quickly. Under high pretension forces, the system exhibited higher shear stiffness in the early stages of shearing due to the influence of the axial force component. With low pretension forces, the ACC exhibited a larger break displacement due to the minor tensile deformation at the shear plane position for the same shear displacement. At low pretension forces, the structure's bending angle increased more rapidly during the middle and later stages of shearing, accompanied by a larger break displacement. Both of these factors led to a greater bending angle at the shear plane position at the point of failure. The results reveal the characteristic of the peak shear load initially increasing and then decreasing with the increase in test block strength, along with its underlying mechanism. As the block strength increased, the bending angle of the structure at the shear plane position increased more rapidly, resulting in higher shear stiffness. With high block strength, the combination of smaller break displacement and greater shear stiffness led to an initial increase followed by a decrease in peak shear load. A comprehensive RSSB (Relative Stiffness between Structure and Test Block) that considers both structural and test block stiffness was proposed. The deformation pattern of the structure was controlled by the RSSB. The higher the RSSB, the wider the plastic hinge extension range for the same shear displacement, the smaller the bending angle at the shear plane position, and the smaller the maximum curvature of the structure. The contact force of the C-shaped tube generally exhibited a "single peak" distribution. As the shear displacement increased, the peak position of the contact force moved away from the shear plane, and the maximum contact force increased rapidly and remained relatively stable. At the end of the shearing process, the contact force of the C-shaped tube exhibited a "double peak" distribution. [ABSTRACT FROM AUTHOR]

Abstract To prevent the early breakage of anchor cables under shear loads in support engineering, a combined structure of Anchor Cable with C-shaped Tube (ACC) has been proposed. The shear resistance enhancement mechanism of this structure and the mechanisms of various influencing factors have yet to be fully revealed. A refined nonlinear finite element model of ACC was original established using ABAQUS software, taking into account the actual structure of the steel strands and the interactions, such as contact and failure between the various components. Various anchor cable pretension forces and block strengths were set to investigate their effects on the shear mechanical response of ACC. The results successfully demonstrated a high correlation between peak shear load and pretension force. The results demonstrate that an increase in pretension force reduces the ACC’s peak shear load and break displacement. Additionally, the structure exhibited higher flexural stiffness, the block strength was mobilized earlier, and the block failed locally more quickly. Under high pretension forces, the system exhibited higher shear stiffness in the early stages of shearing due to the influence of the axial force component. With low pretension forces, the ACC exhibited a larger break displacement due to the minor tensile deformation at the shear plane position for the same shear displacement. At low pretension forces, the structure’s bending angle increased more rapidly during the middle and later stages of shearing, accompanied by a larger break displacement. Both of these factors led to a greater bending angle at the shear plane position at the point of failure. The results reveal the characteristic of the peak shear load initially increasing and then decreasing with the increase in test block strength, along with its underlying mechanism. As the block strength increased, the bending angle of the structure at the shear plane position increased more rapidly, resulting in higher shear stiffness. With high block strength, the combination of smaller break displacement and greater shear stiffness led to an initial increase followed by a decrease in peak shear load. A comprehensive RSSB (Relative Stiffness between Structure and Test Block) that considers both structural and test block stiffness was proposed. The deformation pattern of the structure was controlled by the RSSB. The higher the RSSB, the wider the plastic hinge extension range for the same shear displacement, the smaller the bending angle at the shear plane position, and the smaller the maximum curvature of the structure. The contact force of the C-shaped tube generally exhibited a “single peak” distribution. As the shear displacement increased, the peak position of the contact force moved away from the shear plane, and the maximum contact force increased rapidly and remained relatively stable. At the end of the shearing process, the contact force of the C-shaped tube exhibited a “double peak” distribution.

Abstract To examine the disparity in deformation behavior and mechanical qualities between anchor cables with C-shaped tubes and regular anchor cables under shear conditions. The double-sided shear tests of free-section anchor cables and anchor cables with C-shaped tubes were conducted utilizing the indoor large-scale double-shear test equipment with varying pretension loads. The indoor double-shear tests indicate that the inclusion of the C-shaped tube alters the stress distribution of the anchor cables inside the anchor cables with C-shaped tubes and mitigates the impact of stress concentration. Moreover, it facilitates the transition of the anchor cable's failure mode from a mix of tensile and shear breaking to mainly tensile breakage. In addition, ABAQUS finite element analysis software was used to establish a double shear test model of the anchor cable with C-shaped tube to accurately simulate the interaction and stress distribution among the anchor cable, C-shaped tube, and concrete block in the double shear test. The findings of the simulation results reveal that the numerical model can adequately depict the evolution of the stress distribution in the prestressed anchored structure and the damage of the concrete block with increasing shear displacement. The relational equation for the yield state of the anchor cable with C-shaped tube under combined tensile and shear loads is found by integrating the experimental and simulation data, the static beam theory, and the concept of minimal potential energy.

To examine the disparity in deformation behavior and mechanical qualities between anchor cables with C-shaped tubes and regular anchor cables under shear conditions. The double-sided shear tests of free-section anchor cables and anchor cables with C-shaped tubes were conducted utilizing the indoor large-scale double-shear test equipment with varying pretension loads. The indoor double-shear tests indicate that the inclusion of the C-shaped tube alters the stress distribution of the anchor cables inside the anchor cables with C-shaped tubes and mitigates the impact of stress concentration. Moreover, it facilitates the transition of the anchor cable's failure mode from a mix of tensile and shear breaking to mainly tensile breakage. In addition, ABAQUS finite element analysis software was used to establish a double shear test model of the anchor cable with C-shaped tube to accurately simulate the interaction and stress distribution among the anchor cable, C-shaped tube, and concrete block in the double shear test. The findings of the simulation results reveal that the numerical model can adequately depict the evolution of the stress distribution in the prestressed anchored structure and the damage of the concrete block with increasing shear displacement. The relational equation for the yield state of the anchor cable with C-shaped tube under combined tensile and shear loads is found by integrating the experimental and simulation data, the static beam theory, and the concept of minimal potential energy. [ABSTRACT FROM AUTHOR]

In view of the complex asymmetric deformation characteristics of inclined coal seam roadways and the tensed shear failure of anchor cable supports, the asymmetric support scheme of an anchor cable with a C-shaped tube is proposed. In order to study its supporting effect on an inclined coal seam roadway, this paper first explores the difference in shear performance between an anchor cable with a C-shaped tube and an anchor cable through double shear tests. Then, based on the asymmetric deformation characteristics of an inclined coal seam roadway in the Pangpangta Mine, a numerical simulation is used to study the asymmetric support effect of an anchor cable with a C-shaped tube in an inclined coal seam roadway. The results of the double shear test show that the anchor cable with the C-shaped tube has stronger resistance to shear load than that of the anchor cable. Through the results of the numerical simulation, the original stress field distribution on both sides of the roadway was found to be uneven due to the influence of the coal seam dip angle, and after the excavation of the inclined coal seam roadway, the displacement and plastic zone distribution on both sides showed obvious asymmetric characteristics. Compared with the symmetric support, the asymmetric support can obviously alleviate the asymmetric deformation characteristics of the two sides and effectively control the deformation and plastic failure zone of the roadway. The anchor cable with the C-shaped tube has better resistance to shear deformation than that of the anchor cable. The anchor cable with the C-shaped tube can reduce the deformation and plastic area of the roadway more effectively. [ABSTRACT FROM AUTHOR]

With the increase of coal mining depth, the stress environment of the surrounding rock of the roadway deteriorates, therefore it becomes a prominent problem for the large deformation of the surrounding rock and the breaking of the bolt and cable, which seriously affects the safety of deep mine production.To solve such problems, this paper focuses on the advantages and disadvantages of bolt and cable support.Based on the interaction mechanism between Anchor Cable with C-shaped tube(ACC)and surrounding rock, this paper proposed a new ACC support technology.ACC optimizes the stress state by improving the structure of the free section of the anchor cable.It can not only enhance the anchor cable's axial bearing capacity but also prevent the free section of the anchor cable from breaking due to lateral action.It can avoid the problem of instability of surrounding rock.Through the shear test, it is found that the maximum shear load of the ACC is more than 1.27 times that of the ordinary anchor cable, and the average maximum shear displacement is 1.16 times that of the ordinary anchor cable, which indicates that the ACC has good shear resistance and shear direction extension properties.Based on the engineering case of the roadway of Jiulong Mine, this study analyzes the deformation and failure characteristics of the roadway under the original support scheme through on-site monitoring and borehole detection, and has successfully applied the ACC in the deep large-deformation roadway.The field monitoring results show that the new technology of ACC can effectively control the large deformation of surrounding rock.The results of this study can provide reference for similar deep mine support.

In view of the complex asymmetric deformation characteristics of inclined coal seam roadways and the tensed shear failure of anchor cable supports, the asymmetric support scheme of an anchor cable with a C-shaped tube is proposed. In order to study its supporting effect on an inclined coal seam roadway, this paper first explores the difference in shear performance between an anchor cable with a C-shaped tube and an anchor cable through double shear tests. Then, based on the asymmetric deformation characteristics of an inclined coal seam roadway in the Pangpangta Mine, a numerical simulation is used to study the asymmetric support effect of an anchor cable with a C-shaped tube in an inclined coal seam roadway. The results of the double shear test show that the anchor cable with the C-shaped tube has stronger resistance to shear load than that of the anchor cable. Through the results of the numerical simulation, the original stress field distribution on both sides of the roadway was found to be uneven due to the influence of the coal seam dip angle, and after the excavation of the inclined coal seam roadway, the displacement and plastic zone distribution on both sides showed obvious asymmetric characteristics. Compared with the symmetric support, the asymmetric support can obviously alleviate the asymmetric deformation characteristics of the two sides and effectively control the deformation and plastic failure zone of the roadway. The anchor cable with the C-shaped tube has better resistance to shear deformation than that of the anchor cable. The anchor cable with the C-shaped tube can reduce the deformation and plastic area of the roadway more effectively.

Faced with serious tensile–shear fracturing of anchor bolts and cables in deep roadways, it is of great significance to investigate Anchor Cable with C-shaped tube (ACC), a combined structure of a C-shaped tube and an anchor cable with high strength and shear resistance. The shear mechanical properties of the anchor cable and ACC are systematically investigated using the technical means of theoretical analysis and double-shear tests. The improved equipment for a double-shear test not only considers the initial normal stress but also ensures the continuity of the anchor cable's axial force transmission while considering the influence of the inclination angle on the shear performance of supporting components. The research indicates that the C-shaped tube inhibits the occurrence of stress concentration near the joint surface and improves the stress state of the anchor cable, transforming its failure mode from tensile–shear failure to tensile failure. Compared with the anchor cable, ACC has a higher shear capacity, greater shear stiffness and better ductility in the shear direction. The shear capacity of ACC is higher when it is perpendicular to the joint plane than when inclined to 80°, and the shear capacity of the joint plane is linear with the initial normal stress. Two methods were proposed to contrast the shear capacity between the anchor cable and ACC, including the shear capacity of supporting components and the shear capacity of the joint surface. The former is to evaluate the shear capability of the anchor cable and ACC, while the latter is to evaluate the ability of the anchor cable and ACC to control the shear deformation of the joint surface. The tests results show that the average shear capacity of ACC is 279 kN higher than the anchor cable, with an average increase of 34.9%. The average shear capacity of the joint surface anchored by ACC is 306 kN higher than the anchor cable, with an average increase of 25.2%. ACC can effectively improve the shear capacity of the anchor cable in the free section and has wide application prospects. [ABSTRACT FROM AUTHOR]