Abstract
To explore the bolt-grouting method of the deep roadway under three-dimensional unequal ground stress, a unidirectional coupling model of surrounding rock plastic failure and grouting diffusion considering the influence of excavation disturbance stress was established. Spatial evolution characteristics of plastic failure and grouting diffusion, and the impact of the spacing and row spacing of grouting bolts/cables on grout diffusion, were simulated by using the numerical method. The results revealed that the horizontal ground stress perpendicular to the axial direction of the roadway was the main factor inducing roadway damage. Moreover, the more significant the difference of the ground stress in three directions, the larger the plastic zone of the roof corner and floor corner of the roadway. Under different lateral pressure coefficients, the grout diffused can be approximate ellipsoid and cylinders. Furthermore, the larger the ratio of lateral pressure coefficients perpendicular to and parallel to the axial direction of roadway, the larger the diffusion length of grout in each spatial direction in the surrounding rock. In bolt-grouting support, the length of the grouting bolts/cables should be greater than the plastic zone of the surrounding rock, and the optimal relationship between their spacing and row spacing and diffusion length of grout is determined. The research results were applied in the bolt-grouting engineering for the three-level main roadway in the Haizi Coal Mine, and a good support effect was achieved. This can provide technical guidance and a method of reference for the design and parameter optimization of bolt-grouting support for roadways under deep high ground stress.
Highlights
The demand for mineral resources has been increasing with the rapid growth of the world economy, and shallow mineral resources are gradually depleted
The deep surrounding rock is in an initial equilibrium state under three-dimensional unequal ground stress
The results show theinhorizontal ground larger λ is, that is, the more significant difference of ground stress in three directions, x which is perpendicular to the axial direction of the roadway, is the main factorthe to induc greater the plastic zone in the roof corner and floor corner is, and the damage in the roof roadway failure under the condition of unequal ground stress in three directions
Summary
The demand for mineral resources has been increasing with the rapid growth of the world economy, and shallow mineral resources are gradually depleted. Investigated the influence of the lateral pressure coefficient and principal stress direction on the failure of the roadway These studies provide the theoretical basis for analyzing the effect of ground stress on plastic damage characteristics of tunnels. It is necessary to study further the spatial distribution characteristics of plastic failure of the roadway under three-dimensional unequal ground stress to better guide the grouting support design of fractured surrounding rock. The above study did not consider the influence of three-dimensional unequal ground stress and excavation disturbance on grout diffusion and did not correlate it with the three-dimensional fracture characteristics of surrounding rock It could not effectively and optimally guide the grouting reinforcement engineering practice. Unidirectional Coupling Model of Plastic Failure and Grouting Diffusion in Surrounding Rock
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