Research On Failure Mechanisms And Dynamic Control Technology Of Deep And Large Bedding Slope Of Fushun West Open-pit Coal Mine

Fushun West Open-pit Coal Mine is the largest open-pit mine in Asia.During the continuous mining process,the slope gradually becomes steeper and deeper,which is prone to instability,even landslide.In addition to the special geographical location of the minelocated in the downtown area of Fushun city,the stability of the slope has become the main factor that restricting the sustainable development of the mine and Fushun City at this stage.The south slope of the West Open-pit Mine belongs to the deep and large bedding slope.There is a weak layer in the slope interior and a fault F5 in the middle of the slope which has a restraining effect on the west side of the slope;Due to the asymmetric excavation of the mine,the thickness of the potential landslide on the east and west sides of the slope is inconsistent.The asymmetric backfilling of the open-pit causes the stress distribution at the bottom of the slope to be uneven.The above complex spatial conditions,and the long-term creep deformation of the slope,make the stability problem of the slope very outstanding.The open-pit is nearing the scheduled closed time,but due to the large amount of resources at the bottom of the east region of the open-pit.If the mining activities continue,can the south slope still remain stable in subsequent mining is unknown.If the open-pit closed,how to keep the slope stable for a long time,the existence of these problems makes the systematic research work on the deformation mechanism and stability of the south slope extremely urgent.In view of the above problems,incorporating with the creep experiment,cooperative monitoring method and numerical simulation,this thesis investigates the stability and the deformation mechanisms of the deep and large bedding slope from multi-angle and different region.Additionally,this thesis studies the dynamic stability control of the south slope according to its deformation and stability characteristics.This thesis mainly carried out the following aspects:1.Based on the characteristics of the geological conditions of the south slope of the Fushun west open-pit coal mine,the stability of the south slope was evaluated by the SMR method.The basic parameters of the structural surface of the south slope were obtained by digital photogrammetry technique,and the superior joint groups were obtained.According to the damage characteristics and phenomena of the south slope in-situ,the SMR method is used to analyze the most probable failure place of the slope.2.The characteristics of shear creep experiments of carbonaceous mudstone specimens were studied.The time-strain curves of carbonaceous mudstone specimens under different normal stress conditions were obtained,and the shear creep characteristics were studied.The relationship between creep strain and time,creep rate at steady stage,creep characteristics at failure stage,rock creep failure characteristics and crack propagation characteristics on the specimens' surface were analyzed.3.The large deformation mechanisms of the west region of the south slope were analyzed,and the dynamic shear strength parameters of carbonaceous mudstone were obtained.According to the shear creep experiment,the ultimate strain of the carbonaceous mudstone is obtained,and then the ultimate deformation of the slope is obtained.The large deformation mechanism of the west region of the south slope is analyzed.The nonlinear shear creep equation of the carbonaceous mudstone is established.The creep equation is used to fit the experimental data,and the creep parameters in the equation are obtained.Combined with the ultimate strain of carbonaceous mudstone,the dynamic shear strength parameters of the carbonaceous mudstone weak layer decay with time are obtained.4.The three-dimensional space failure mechanisms of super large asymmetric landsliding block of the south slope were analyzed.Incorporating with the on-site measurement,satellite monitoring technique and microseismic monitoring,the deformation process of the rock mass near the west boundary of the landslide in the west part of the south slope was analyzed,and the west boundary shape was determined.Combing with the numerical simulation and the satellite monitoring technique,the deformation process and failure mechanism of the super large asymmetric landsliding block of the south slope were analyzed.5.A systematic analysis of the stability of the east region of the south slope under different geological and mining conditions was carried out,and the deformation trends of the slope after asymmetric backfilling were studied.The thickness and angle of the landslide,the excavation depth,the backfill height,the different angle of the bedding fault and counter-inclined fault,the different water conditions and the underground mining which affecting the stability of the slope were considered to analyze the possible failure mode and deformation law of the slope.Furthermore,the deformation characteristics and law of the slope after the asymmetric backfilling were investigated and the differences of deformation characteristics between east slope and west slope were analyzed.6.According to the deformation and stability variation characteristics of the south slope with time,the dynamic stability control technology of slope is proposed.Based on the dynamic shear strength parameters of the weak layer of the slope,the development trend of the deformation and stability of the slope is analyzed.Combined with the deformation and stability characteristics of the slope,the dynamic stability control technology of the slope is proposed.The local micro-pile group reinforcement was adopted for the West Kengkou refinery,and the research on the reinforcement mechanisms and effects were carried out.