| There is a huge number of open-pit mining in China, study of large dump site base load capacity and slope stability has great significance, especially in the higher rainfall areas in southern China. Dump site slope in the structure are different from rock slope, so the research methods are different.Through the combination of field and laboratory testing methods, obtained Yongping Copper Mine dump site granular soil and rock particle size distribution and physical and mechanical properties, in some basis, Yongping Copper Mine dump site base load dump capacity, slope stability and the possibility of debris flow in areas such as research, and how to improve the dump site slope stability and to prevent debris flow generation, the following measures:1. aspects of foundation bearing capacityTo take full advantage of space-based soil dumping their strength, to prevent occurrence of the end of the drum to raise the foundation bearing capacity, thereby enhancing the stability of dump, dumping process recommended the following measures:①Bottom dump discharge or permeable good chunk of materials, excavation and backfill large row of sewer water to speed up the foundation to accelerate the rate of drainage and consolidation to improve the foundation soil shear strength.②Control forward speed should not dump too fast, while strengthening the foundation deformation and pore pressure observations, such as deformation and stability after the advance.③Early dump can not be the first layer of soil piled too high, not more than 2.6m, and other drainage and consolidation of foundation soil and then ranked by the force of the high mound. Dump the current step④Height 78m, according to the foundation bearing capacity of the maximum step height is 89.6m, thus also based on the increase in the existing height of the height of dump, but have to pay attention and dump ground deformation, prevent deformation is too large, it is recommended to set the displacement and pore pressure observation system.2.slope stabilityAnalysis by the foundation bearing capacity and slope stability analysis, the existing dump height is stable overall, but there are two potential sliding surface, one is inclined soft soil foundation and caused the slope itself is due to the existence of a slip potential trends, the impact of rainfall on slope stability greatly. In order to prevent the development of potential slip surfaces to ensure mine safety, we recommend the following measures:①Dump load to make best use of motor vehicles and bulldozers rolled dump uniform platform to accelerate their consolidation dump, on the other hand, soil can not fast forward speed to fully enhance and use their strength dump site.②Strengthening dump operation technology management. Dumping operations will be reasonable and stacking of materials of different lithology, the surface soil and weathered rock should be stacked properly control the amount of time or control the stacking velocity, so as not to face an advancing distance caused excessive settlement rate, composition new sliding surface. Usually the steps in the separation of production and dump site dump line and the standby line, each rotation operation, so that a reasonable dumping.③Platform dump site to be flat to 2% to 3% of the anti-slope, in order to facilitate centralized drainage, prevent the formation of slope erosion; dump site dump during the rainy season, especially when the rain intensity greater than continuing to ask the time dumping should be stopped long, and so began to dissipate pore water pressure to continue dumping operations, while strengthening the drainage measures.④Platform to the most eyebrow line outside the transportation line between thesafe distance of not less than 1.5m. At the same time put an end to the destruction of toe, to prevent local villagers digging the bottom of the residual ore dump site.3.the debris flow preventionYongping copper mine dump site west of the conditions exist to form debris flows, debris flows by gravity type (slide type) the main debris flow, debris flow is viscous; rare hydrodynamic debris flow, generally due to improper artificial slope and surface runoff erosion formation. Therefore, Yongping Copper Mine in the analysis of the causes and prevention of debris flow, landslide debris flow focus.According to the results of stability of dump site and field situation, soil stability is good overall, produce the landslide along the entire foundation is unlikely, prone to landslides and debris flows in parts of the main steps in the new top of the abandoned and the local soft ground along the bottom of the drum and sliding, it is expected that the size of debris produced is not great. ①As previously mentioned measures taken to enhance slope stability and reduce the likelihood of debris flow.②Dump site surface water treatment. Dump the formation of debris flow mainly depends on surface water and rainwater on dump site the role of erosion and erosion, then strengthen the dump surface itself and its surrounding catchments governance is clearly essential, greatly reduced if the water , then can control the occurrence of debris flow or only a very small local scale. On the one hand to the construction of drainage channel, blocking the field trip dumping dump site water into the sink; the other hand, a platform dump site to be flat to 2% to 3% of the anti-slope, to prevent waste dump site platform itself catchments slope into the slope and erosion, the exchange of water from the dump area to minimize infiltration dump site.③Debris flow in order to protect farmland downstream industrial facilities and the safety of debris flow control based on experience of mine in the area and stop the flow of debris build pollute reserve area appropriate dam, dam and other structures in bamboo cages to Landang solid debris washed down material .④Dump site vegetation, slope protection is not conducive to rainfall, reducing infiltration of water inside the dump site.⑤Debris flow due to lack of the necessary site monitoring, data mining and other meteorological observations, this study does not include the contents of debris flow forecast. From FLAC3D simulation results, when the rainfall intensity is larger, more continuous rainfall for more than 15d, dump site was gradually moving to limit state may decline, and even the formation of debris flow. Therefore, continuous rain can be a warning time of 15d, used as a basis for determining the initial formation of debris flow, to 15d, when this rain, they should take appropriate drainage, drainage measures, the impact of reduced water. |
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