Physical Model Experiment On Mechanism Of Bedding Landslide In 2011-1005 Of Nanfen Open-Pit Mine

For a long time,geological disasters are very serious in China,among which landslide is the most harmful geological disaster in China,causing billions of economic losses every year,causing hundreds of casualties.Because of the influence of geological conditions and mining blasting,Nanfen open pit mine in Liaoning Province has become a high incidence area of landslide disaster.In addition to the centralized mining work of equipment and personnel,each disaster will cause serious consequences.Therefore,how to reduce or avoid the landslide disaster in mining area,how to ensure the safety of life and property,is a significant topic.On the basis of consulting a large number of research documents and geological exploration data,this paper fully combines the relevant knowledge of engineering geology,rock mechanics,physical model experiment,measurement mechanics,modern communication technology and many other scientific fields,and starts from geological exploration data and 2011-1005 landslide features,carries out physical model experiment,based on which the failure mechanism of this landslide is analyzed in detail And the main influencing factors.Based on the research results,combined with the working principle and field application of the remote monitoring and early warning system of Newtonian force of landslide,it has created significant benefits for the excavation,protection,monitoring and early warning of landslide disaster in Nanfen open pit mine,and also provided support for the popularization and application of the remote monitoring and early warning system of Newtonian force of landslide.The specific work and research results are as follows:(1)analyze the geological exploration data of Nanfen open pit iron mine,master its topography,hydrogeology and joint distribution,and study the important factors affecting the slope stability.The analysis shows that the main landform of Nanfen Open-pit Iron Mine is the middle high mountain landform of erosion structure.Affected by monsoon climate,rainfall is abundant.The iron ore is very suitable for open-pit mining and has excellent properties,so it is the best raw material for ironsmelting.The footwall area in the mining area is a serious disaster area of the landslide,which is mainly affected by two sets of joints,forming an obvious weak sliding surface,which is harmful to the stability of the slope.According to the change trend of Newtonian force,the newly introduced remote monitoring and early warning system of Nanfen sent out early warning signals for2011-1005 landslide 2 days in advance,which was a successful application.The method of stereographic projection is used to judge the failure mode of 2011-1005 landslide.Based on the analysis of the failure characteristics of the structural plane of the landslide and the monitoring coupling curve of the monitoring and early warning system in a short period of time,it is concluded that rainfall is the inducing factor of the landslide and excavation is the main factor.(2)physical model experiment is based on the similarity principle to study the relationship between geological structure and engineering activities,which can guide engineering how to deal with geological disasters.Taking Nanfen 2011-1005 landslide as an engineering prototype,a large scale physical model experiment was carried out.In this paper,the influence of excavation on the stability of slope with weak structural plane under preloading is studied,and the feasibility of the system is verified by combining the principle of remote monitoring and early warning system.The experimental results show that the weak structural plane does have a certain impact on the stability of the slope.Like the famous barrel theory,the weak sliding plane is the shortest plate of the whole landslide,which determines the upper limit of the anti sliding force.Preloading also has an effect,but does not cause significant changes in displacement and sliding force.The excavation will weaken or eliminate the lateral support force of the slope,resulting in the upper slope loose and collapse,especially under the conditions of soft sliding surface and preloading(such as weathering,rainfall,blasting,etc.),it will cause the displacement of the upper rock mass to increase,the overall slope sliding,resulting in landslide disaster.(3)after the successful research and development of the long-distance monitoring and early warning system of landslide,the continuity of monitoring data is ensured.Combined with the basic theoretical system of sliding force,the system is guaranteed both in theory and practice.At the same time,with the help of modern communication technology,it has been successfully applied in 481 monitoring points in 18 regions of the country.It has been successfully predicted 11 times of landslide disaster,which has significant social and economic benefits.The monitoring and early warning system is composed of four components:constant resistance and large deformation anchor,purple bee wireless communication technology,Beidou satellite and data receiving and processing system.The components are closely linked to form an organic whole.The mechanism and cause of landslides in 2013-0223 and 2013-0225 of Nanfen Open Pit Iron Mine are analyzed through practical engineering application,and the effectiveness of remote monitoring and early warning system of landslides is verified by real cases.The experience and mode of monitoring and early warning issued by the system according to the change of sliding force are accumulated to provide help for the promotion and application of the system.