| In the condition of underground mining combined with open-pit mining, mining effect will be superposed. Mining slope will receive several induced stress fields and the sliding mechanism and deformation law of slope rock mass will be more complicated. Frequent occurrence of accidents of open pit slope collapse and surface subsidence, landslides and other disasters dump caused by underground mining leading to an increase of the open slope and dump maintenance costs, brought about huge economic losses, what's more, the direct impact on mine safety production. Therefore, the research on Slope Damage Mechanism and control technology under the combinational action of two mining approaches is necessary. This paper, taking Pingshuo Coal Industry Corporation Antaibao not mining district of combined mining as engineering background, adopts methods and means of theoretical analysis, field geological survey and test pit and underground mining effect of slope and rock mining damage related to deformation monitoring, indoor numerical calculation to explore the role of open pit and underground mining slope damage mechanism and the technology of Slope Stability Control. The main research results are:(1) The damage mechanism of slope shows time-and-space effects under circumstances in which both underground mining and open-pit mining are employed, and slope mass will emerge two typical sliding phenomenon with joint effects:the one is rock mass sliding along the slope, and the other droping to the deep mining gob. Rock mass will produce the overall displacement along slope inclination with a relative high rate in the early period of underground mining. However, the movement will gradually tend to be stable with overburden rock caving and filling into mining gob.(2) Displacement and movement rate of slope mass increases obviously in the situation of joint effect than that single open-pit mining, and slope movement in combinational mining mainly exhibits as the deformation caused by underground mining.(3) Slope displacement range and size shows quite difference associated with different spatial relations between open pit slope and mining gob and direction of slope inclination and mining exploitation. In the condition of reverse slope mining, slope mass dumps to free face in early-stage and then gradually turn to subsidence movement inside slope. While down-slope mining, rock mass at the top of slope mainly conducts subsidence displacement to gob, and security mining pillars at the foot move to less resistance free-surface. And in the situation of lateral cut slope mining, slope makes the whole movement to its free-face. Surface movement basin appears non-symmetrical distribution and slope foot presents bulging deformation.(4) Under the complex mining condition, caving zone, fault zone and bending zone caused by shallow ore body mining develop to pit slope firstly, and then the "three zones" in deep ore mining will effect on the area. Therefore measures and solutions should be done in time to deal with the shallow mining gob to prevent large rock-burst disaster caused by sudden collapse of overlying strata due to second disturbance.(5) There are many different perspectives to improve slope stability in the condition of combinational mining. Firstly, adequate width security pillar should be provided in advance to withstand bias formed during underground mining; the second is to cut some top of slope to reduce the bias load shedding to mitigate stress concentration of the security pillars at the foot; thirdly, filling back of foot slope can help to increase skid-resistance; fourth, surface cracks appearing on slope should be filled compaction to avoid rainwater seeping down and the influence to slope.(6) Slope stability control and slope maintaining quickly and ecological restoration technology are proposed under condition of open-pit mining combined with underground mining based on understanding slope damage mechanism, considering minimize transport work of goaf and minimize environmental impacts of mining.
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