Seepage Characteristics of Collapse Column under the Influence of Mining

To study the change laws of stress and the seepage characteristics under the influence of the stress with the mining face closes to the collapse columns,two numerical models were established based on FLAC^3D fluid-solid coupling model,and the impact of the stress changes near the working face on the stress field and seepage field of the collapse columns were analyzed.The results showed that the collapse column successively laid in the areas of advanced support pressure zone and unloading zone,which led to its stress first increased and then decreased,thus caused the changes of seepage field.Water decreased in the collapse column,and pressure of the water head was 0.Compare to the collapse column which hidden under the floor,when the collapse column penetrated the coal,the workface was closer from the aquifer and mining had a greater impact on the collapse column,then the water head grew higher.Actual project should strengthen monitoring and prevention for this case.