Flexible Cushion Design Roots Duixia Lying Dry Iron Ore Tailings

With the rapid development of China’s economy, mineral resources are in great demand; shallow resources are drying up and many of open-pit mining into underground mining. Two major challenges facing the most open-pit mining to underground mining are that tailings capacity is insufficient and the new tailings land acquisition is difficult. These lead some mine to increase the height of dam body to expand capacity and bring some potential safe problems. The random discharge of tailings in mines causes river siltation and serious environmental pollution. Taking into consideration of security, abandoned open-pit gobs haven’t gotten very good development and utilization due to the space position relationship with the underground stope.With the background of dry heaping technique of tailings in Louci Iron Ore open-pit gobs, this thesis creatively puts forwards the technical disposal scheme about setting reinforced concrete flexible cushion with the characteristics of flexible as a whole and rigid in part between the open-pit bottom and the dry heaping tailings. Under the guidance of Professor Hou Kepeng in Kunming University of Science and Technology, the purpose of this thesis is to explore the new ways of development and utilization in abandoned open-pit mines. The main contents are as follows.(1) Based on the indoor drawing tests, the feasibility of setting flexible cushion layer is proved.(2) Combined with micro and experience, the possibility of dry tailings’vibration liquefaction is decided and it’s small.(3) According to the research results of the soil arcingh theory, when tailings heaped on the flexible cushion layer, it is put forward that the maximum force on the flexible cushion layer is the weight of tailings in double arch height.(4) A mechanical motion model about the flexible cushion’s coupling displacement with the discharge of waste rock, the force bearing formulas of steel strand and the selection method of steel strand are proposed.(5) Using the numerical software PFC2D,the granular microscopic parameters of the force on the floor are calibrated as the weight of tailings in double arch height.(6) Using the numerical software PFC2D,it’s reproduced that the loose medium in the process of natural sedimentation presents a W change in high porosity and a arching effect in sections, and the mechanics regularity of floors is consistent with the laboratory test and the soil arch theory.(7) Through the numerical software PFC2D,the mechanical motion model about flexible cushion moving with the tailings and waste rocks and the reinforcements are validated correctly,and properly setting the flexible cushion helps separate dry tailings from waste rocks.(8) When extending the flexible cushion layer, it’s put forward that the specifications of the steel strand should increase as the extended size increase.