| In the field of roadway blasting excavation engineering,in order to achieve the expected effect of blasting into the roadway,improve the stress state of the anchored rock mass affected by the blasting dynamic load,improve the stability of the project,and analyze the damage characteristics of the anchored rock mass under the blasting dynamic load.Extremely important.Due to the requirements of construction schedule,it is often necessary to alternate the blasting operation and the roadway support operation.The blasting excavation of the roadway will inevitably affect the anchoring system.After analysis and research,the influence of the blasting dynamic load on the anchoring system has an impact area.The dynamic damage of anchored rock mass is studied in the area.The damage degree of surrounding rock is reduced by reasonable optimization of blasting and support parameters,and the applicable service life of the roadway is increased.In this paper,the effects of blasting dynamic load on the dynamic damage of anchored rock mass are analyzed by theoretical analysis,numerical simulation and engineering measurement.Through the theoretical analysis,the surrounding rock under the influence of blasting dynamic load is divided;the ANSYS software is used to simulate the crack propagation of surrounding rock to explore the law of crack propagation;the stress wave theory is used to study the simple harmonic of the anchoring system in the plane by the wave potential function expansion method.The dynamic response under the action,and the stress state under the static and dynamic conditions of the anchored rock mass are analyzed.The factors affecting the damage of the anchored rock mass by one blasting and millisecond blasting are analyzed by numerical simulation software.The cumulative damage of anchored rock mass is explored;the feasibility of theory and simulation is verified by engineering measurements.Through three research methods,the understanding and conclusions obtained are as follows:(1)The crack propagation process during the blasting of the simulated tunnel section,the crack development between the blastholes is obtained,and the crack propagation law of the surrounding rock is revealed.(2)Using the polar coordinate tool to analyze the maximum normal stress value when the angle between the incident wave and the anchoring system is 0° and180°,and the minimum normal stress value when the angle is 90°and 270°;theaxial and radial directions are The value of the axial normal stress in the tangential normal stress is the smallest.(3)By analyzing the interaction between the prestressing and the anchoring system,the force transfer law of the prestress in the anchoring system is obtained;under the action of the prestressing,the tensile stress at the anchor-anchor interface and the surrounding rock mass is stronger.Under the action of blasting dynamic load,the area is susceptible to damage or damage caused by dynamic loads.(4)Using ANSYS software to simulate the damage model of anchored rock mass under the action of one blasting and millisecond blasting,it is concluded that the anchorage rock mass of the roadway roof is subjected to large stress;by exploring the distance between the anchoring rock mass and the surface distance of the roadway,the stress and The relationship between the vibration velocity of the particle,the nonlinear relationship between the damage and the distance is obtained,and the damage and stress and the vibration velocity of the particle are nonlinearly increasing.(5)Taking the Yuanzigou coal mine as the engineering background,the engineering blasting operation was carried out in the west wing of the No.2 return airway.The data was detected by the RSM-SY5 acoustic wave tester.It was found that the cumulative damage of the anchored rock mass under the cyclic blasting is not simple.The damage superposition;there is a non-linear growth relationship between the damage and the number of blasting,but the growth rate decreases with the advancement of the working surface. |
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