Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effe...Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effective rockburst control. In this study, the squeezing behavior of the surrounding rock is analyzed in rockburst roadways, and a mechanical model of rockbursts is established considering the dynamic support stress, thus deriving formulas and providing characteristic curves for describing the interaction between the support and surrounding rock. Design principles and parameters of supports for rockburst control are proposed. The results show that only when the geostress magnitude exceeds a critical value can it drive the formation of rockburst conditions. The main factors influencing the convergence response and rockburst occurrence around roadways are geostress, rock brittleness, uniaxial compressive strength, and roadway excavation size. Roadway support devices can play a role in controlling rockburst by suppressing the squeezing evolution of the surrounding rock towards instability points of rockburst. Further, the higher the strength and the longer the impact stroke of support devices with constant resistance, the more easily multiple balance points can be formed with the surrounding rock to control rockburst occurrence. Supports with long impact stroke allow adaptation to varying geostress levels around the roadway, aiding in rockburst control. The results offer a quantitative method for designing support systems for rockburst-prone roadways. The design criterion of supports is determined by the intersection between the convergence curve of the surrounding rock and the squeezing deformation curve of the support devices.展开更多
The axial direction of a roadway often forms a certain spatial angle with the in-situ stress field.Variations in the spatial angles can lead to differences in the stress environment in which the roadway is exposed.Dif...The axial direction of a roadway often forms a certain spatial angle with the in-situ stress field.Variations in the spatial angles can lead to differences in the stress environment in which the roadway is exposed.Different forms of failure characteristics occur in the roadway.In order to study the failure mechanism with different spatial characteristics,rock-like material specimens with holes in 9 different horizontal and vertical angles were designed.The true triaxial test system was used to carry out the test with the same loading path.The results show that the horizontal angle a and vertical angle β have a significant effect on the specimen strength,specimen rupture angle,and the form of spalling failure in the hole.The spatial angle leads to the formation of asymmetric heterotype V-notches in both sides within the hole.The asymmetry is evident in both the depth and extent of spalling.The strength of the specimen increases and then decreases with increasing vertical angle β.The rupture angle increases and then decreases with increasing horizontal angle a and increases with the increase of the vertical angle β.The stress analytical model of the specimen under three-dimensional compression was established.The distribution of principal stresses around the holes was theoretically analyzed.It is found that the presence of spatial angle changes the distribution of principal stresses around the hole from symmetric to asymmetric distribution.The shift of the principal stresses is responsible for the change from a V-notch to a heterotype V-notch.展开更多
基金funded by the National Natural Science Foundation of China (No. 52304133)the National Key R&D Program of China (No. 2022YFC3004605)the Department of Science and Technology of Liaoning Province (No. 2023-BS-083)。
文摘Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effective rockburst control. In this study, the squeezing behavior of the surrounding rock is analyzed in rockburst roadways, and a mechanical model of rockbursts is established considering the dynamic support stress, thus deriving formulas and providing characteristic curves for describing the interaction between the support and surrounding rock. Design principles and parameters of supports for rockburst control are proposed. The results show that only when the geostress magnitude exceeds a critical value can it drive the formation of rockburst conditions. The main factors influencing the convergence response and rockburst occurrence around roadways are geostress, rock brittleness, uniaxial compressive strength, and roadway excavation size. Roadway support devices can play a role in controlling rockburst by suppressing the squeezing evolution of the surrounding rock towards instability points of rockburst. Further, the higher the strength and the longer the impact stroke of support devices with constant resistance, the more easily multiple balance points can be formed with the surrounding rock to control rockburst occurrence. Supports with long impact stroke allow adaptation to varying geostress levels around the roadway, aiding in rockburst control. The results offer a quantitative method for designing support systems for rockburst-prone roadways. The design criterion of supports is determined by the intersection between the convergence curve of the surrounding rock and the squeezing deformation curve of the support devices.
基金supported by the NSFC projects(Nos.52225404,42321002,4204100030)Beijing Outstanding Young Scientist Program(No.BJJWZYJH01201911413037)the Excellent Youth Team of the Central Universities of China(No.2023YQTD01).
文摘The axial direction of a roadway often forms a certain spatial angle with the in-situ stress field.Variations in the spatial angles can lead to differences in the stress environment in which the roadway is exposed.Different forms of failure characteristics occur in the roadway.In order to study the failure mechanism with different spatial characteristics,rock-like material specimens with holes in 9 different horizontal and vertical angles were designed.The true triaxial test system was used to carry out the test with the same loading path.The results show that the horizontal angle a and vertical angle β have a significant effect on the specimen strength,specimen rupture angle,and the form of spalling failure in the hole.The spatial angle leads to the formation of asymmetric heterotype V-notches in both sides within the hole.The asymmetry is evident in both the depth and extent of spalling.The strength of the specimen increases and then decreases with increasing vertical angle β.The rupture angle increases and then decreases with increasing horizontal angle a and increases with the increase of the vertical angle β.The stress analytical model of the specimen under three-dimensional compression was established.The distribution of principal stresses around the holes was theoretically analyzed.It is found that the presence of spatial angle changes the distribution of principal stresses around the hole from symmetric to asymmetric distribution.The shift of the principal stresses is responsible for the change from a V-notch to a heterotype V-notch.
