Stability Analysis And Treatment Measures Of Cavity In Longtan Village Mine

Because of the ground pressure,rock weathering and blasting vibration,a large number of cavities in the open pit mining are collapsing and destroying.And the volume and height are changed.The residual multi-layer cavities are complex.With the development of open pit mining,these complicated cavities are a serious threat for people and equipment.Meanwhile,a small part of the cavity has collapsed on the south side of the open pit.Therefore,it is insecurity to opencast mine in the upper part.In order to ensure the safety and to prevent the collapse of the cavities,the stability of cavities must be analyzed.Based on the investigation of the status quo of Longtan Iron Mine,the dominant factors are summarized as the height of the cavities,the span of the cavities and existence time.The decay law of blasting vibration speed and main frequency in different directions of stope is obtained through experiments,which provides the data foundation for dynamic load analysis.The numerical model is based on ANSYS software and loads dynamic and static conditions The analysis shows that the displacement and stress of the cavities are small,and the stress values are far less than the tensile strength and compressive strength,the cavities stand stable.But the stability of the cavities which are closed to the blasting zone are extremely poor under the dynamic load.The vibration velocity exceeds the upper limit of safety vibration.The stability of the cavities farther away from the blasting zone are also poor.The vibration velocity exceeds the lower limit of the safe vibration velocity.Since the charges of the test experiments are minimal,the blasting vibration velocity still exceeds the lower and upper limit,which shows a great influence on the cavities.It's necessary to handle the cavities in time for the normal conduct of production activities.By analyzing the treatment of empty areas and the actual mine,confirm the use of filling method for cavities,and the order is determined.Meanwhile,different filling schemes,including the filling paths and materials are based on the actual situation of mined-out areas,and the amount of filling materials and filling engineering quantities are calculated.