Analysis On Geological Characteristics And Mechanism Of Landslide In South Slope Of West Open-pit Mine In Fushun

After a hundred years of mining,Fushun West Open-pit Mine has formed a large mining pit with a depth of 420 m and a total area of 10.87km2.Due to years of high-intensity mining and geological structural factors,the instability of the slope has been triggered,and geological disasters such as collapse,landslide and ground collapse have occurred many times.There have been recorded landslides in history for more than 90 times.In August 2010,there was a ground fissure at the top of the landslide in south slope of West Open-pit Mine.The cracks continued to extend at widen and deepen.When the system was investigated in early 2012,the ground fissures were generally the north one and the south one.An east-west curved exhibition.At present,the west open-pit mine has an inverted fan shape on the plane.The trailing edge(south side)is wide,and the leading edge(north side)is slightly closed.The north-south width is about 1200-1500 m,and the east-west length is about 3100m;the landslide body is vertical.The height difference is 400-500 m,and the main sliding direction is the northward(inside the pit).The main sliding surface has two layers,and the main sliding surface is buried between 80 and 252 m.The projected area of the landslide body is 3.37km2,and the landslide volume is about 3.12~452 million m3,which is a giant deep rock landslide.Due to the western open-pit mine and many enterprises and residents that are being produced around the landslide in south slope of West Open-pit Mine in Fushun,once it become disasters,it threaten a large number of people and threaten assets.Therefore,the research on landslide exploration and deformation monitoring is very necessary for landslide stability evaluation,forecasting and government decision-making.This thesis takes the landslide in south slope of West Open-pit Mine in Fushun as the research object.Based on the full understanding of the geological environment conditions,the data of the geological disaster investigation,disaster exploration and deformation monitoring are used reasonably,the motion generalization model of landslide activity law is summarized and established according to the established m otion generalization model.The residual shear strength recovery of the slip zone soil and the change of groundwater level are used to study the deformation and failure mechanism of the landslide in south slope of West Open-pit Mine in F ush un.T he m ain res ea rc h r esul ts o btain e d ar e a s foll o ws:(1)Determine the geological characteristics and deformation characteristics of the landslide in south slope of West Open-pit Mine in Fushun.The landslide in south slope of West Open-pit Mine in Fushun belongs to a large-scale deep and bedding rock landslide.There are two sliding surfaces,namely the unconformity contact surface of granitic gneiss and basalt and the weak structural surface of basalt rock mass,which defines the east-west boundary of the landslide.(2)The temporal and spatial distribution characteristics of landslide deformation are studied in detail.The F5-1 fault and the boiler house-Qiantai Hotel's east-dipping fault are used as two dividing lines,and the entire landslide in south slope of West Open-pit Mine is divided into three areas: east,middle and west.Combined with the historical deformation curve of monitoring results,the landslide deformation evolution process is divided into four stages: initial deformation stage,constant velocity deformation stage,accelerated deformation stage and continuous deformation stage.(3)The formation and development mechanism of the landslide was studied.Under the influence of coal mining disturbance,the south side slope of the landslide in south slope of West Open-pit Mine cut off a certain level when the pit was widened and deepened,resulting in the rock mass being in a vacant state,and the natural balance state of the primary rock formation was broken.The middle and upper slopes are driven by the self-gravity to produce a smooth layer along the weak interlayer,and the trailing edge forms a steep ridge and a ground crack.Because the upper rock layer has a greater effect on the thrust of the lower rock mass,the upper rock layer causes the rock stratum at the foot of the slope to be bent and deformed under the action of thrust,and the bottom rock body is shear-damaged to form a shear sliding surface,which is cut out from the foot of the slope to form Large landslide with upper layer and lower layer.