Locational characteristics of damage on buildings around the West Open pit Mine

With the exploitation of Fushun West Open-pit Mine in the past 100 years,some ground fissures and surface subsidence induced by mining cause some buildings cracking,tilting and even being pulled down,which seriously affect the life of residents at surrounding areas.Through the detailed investigation of buildings over 36 km2 in the surrounding urban area of West Open-pit Mine and the comprehensive analysis of the geological conditions and surface monitoring data,and numerical simulation,the laws of surface deformation in the slope-affected area were obtained.The damage characteristics of buildings were presented regarding to the construction age,structural form and locations with respect to different distances from the mine slope.Suggestions and mitigation measures for buildings reinforcement at different locations were put forward.The study shows that the masonry structural buildings are easier to be damaged than the reinforced concrete frame structure.The damage mechanism can be regionalized as unloading deformation within 0-100 m apart from the north side of the slope,surface subsidence within 100-500 m apart from the north side of the slope,ground cracking within 500-700 m apart from the north side of the slope and 0-600 m apart from the south side of the slope.In the unloading deformation area,due to the displacement toward into the open pit of the north side,the foundation of the buildings is subjected to shear damage,and the upper wall is affected by the uneven settlement of the foundation to generate cracks.In the surface subsidence area,due to the north side “triangular wedge-shaped body” dumped to the south,the wall of the building located on the outer edge of the subsidence area tends to be dislocated.In the ground fissure area,due to the uneven settlement caused by ground fissure activity,the wall of the building is sheared and damaged.Based on the damage characteristics of the buildings,some suggestions for reinforcing the buildings at different distances apart from the boundaries of the open-pit were proposed.On the north side of the open-pit,within 0-100 m,the reinforcement should be focused on the foundations of buildings;within 100-500 m,the key reinforcement should pay attention on the walls,beams and pillars of buildings;within 500-700 m,the key reinforcement should be better to be applied to the walls and balconies of buildings.On the south side of the open-pit,within 0-200 m,the key reinforcement should be implemented on the foundations of buildings,and within 200-600 m,on the walls and beams of the buildings.