Optimization Study on the Width of Narrow Coal Pillar along the Goaf Tunnel with Peridynamics
Coal-rock mass exhibits extremely complex and discontinuous deformation,as well as het-erogeneous characteristics.Traditional numerical methods,such as the finite element method(FEM),are difficult to accurately describe the entire process of damage accumulation and progressive failure.Based on the non-local peridynamics(PD)method,the corresponding micro-modulus function and critical elongation are derived by reconstructing the kernel function of the constitutive force function.This approach intro-duces heterogeneity by incorporating random pre-breaking bonds into the homogeneous discrete model.As a result,peridynamics can be applied to the simulation and analysis of deformation and failure of natural heterogeneous materials and structures.Taking the Fucun coal mine as an example,a heterogeneous peri-dynamics simulation model is established.The deformation and failure laws of the roadway's surrounding rock and failure characteristics of coal pillars with different widths are analyzed.It is found that when the width of the coal pillar is 5 m,the roadway is at the edge of the extrusion deformation zone.The signifi-cant change in abutment pressure results in severe deformation and damage to the roadway's surrounding rock.When the width of the coal pillar increases to 6 m and 7 m,the roadway's surrounding rock gradual-ly moves away from the extrusion deformation area.Consequently,the influence of the basic roof rotation movement in the goaf on the coal pillar weakens,resulting in reduced deformation and damage to the road-way.However,when the width of the coal pillar continues to increase,the roadway's surrounding rock enters an area where the stress increases.The high bearing pressure from the external stress field leads to an increase in deformation and damage to the roadway.Considering the deformation and damage character-istics of the roadway's surrounding rock and coal pillar,a reserved width of 7 m for the coal pillar is finally determined.The proposed peridynamics simulation model provides a new and effective simulation tool for optimizing the size of coal pillars in gob-side entry driving.
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