Study On Landslide Warning Method Based On Surface Displacement Monitoring And Numerical Simulation

Geological disasters occur frequently in my country,and disaster losses are very serious.Landslides are the most common form of disasters.The formation mechanism of landslides is complex and there are many factors affecting stability.Landslide prevention and control is a scientific problem that has long plagued geologists.With the development of science and technology,early warning and forecast based on deformation monitoring have become the main means to prevent landslides.Monitoring and forecasting play an important role in disaster prevention and mitigation activities.Geologists have been working on landslide monitoring since the1920 s,Over the past decades,monitoring technology has developed by leaps and bounds,and an integrated air-space-ground monitoring system has been gradually established,making it possible to make accurate landslide warning and forecasting.The current monitoring-based landslide prediction methods can be roughly divided into two categories,one is the cumulative displacement judgment method,and the other is the deformation rate judgment method.The cumulative displacement method is based on engineering experience or the threshold recommended by the specification for early warning judgment.The disadvantage is that the study of the specific engineering geological characteristics of the landslide is often ignored.The threshold is determined by most subjective factors and the compliance is poor.In the past 20 years,the deformation rate method has become an important method for landslide prediction.Its main principle is to infer whether the landslide is in a state of imminent sliding by identifying the degree of sharp deformation of the landslide,however,in engineering practice,the monitoring displacement curve often appears in the form of a slip curve,so the probability of false alarms is relatively high.During the evolution cycle of the landslide,the cumulative deformation to destructive sliding is roughly a certain value(critical displacement),which is determined by the engineering geological conditions of the landslide.Therefore,landslide monitoring should be carried out on the basis of landslide engineering geology research,and early warning and forecasting should focus on the evolution stage of the landslide approaching the critical displacement.Studies have shown that for accumulative landslides and rock landslides with time-dependent deformation such as overlying bedrocks and strong weathering zones,the critical displacements of different single landslides are not the same,and there is no unified critical displacement.Based on this,the critical displacement and the “dual index” of the tangent angle of the T-t curve are used as thresholds for landslide prediction and forecasting.That is: when the landslide deformation is close to the critical displacement and the tangent angle increases sharply,the landslide is in the stage of dangerous deformation and the possibility of destructive sliding is the greatest,and a high-level warning should be given;When the cumulative deformation of the landslide is much smaller than the critical displacement,the increase of the T-t tangent angle may be caused by some sudden factors to cause a short process of rapid deformation,which will not cause a destructive slide,High-level warnings may not be given,thereby reducing the probability of false alarms.This paper takes the Kailin large water landslide as an engineering example,explains the specific operation method of the warning method,And established a four-level warning level based on the critical displacement value and improved tangent angle,In addition,this article also conducts research on the deformation prediction model in order to be used in conjunction with the critical displacement value and the improved tangent angle "dual index" method.It has certain guiding significance for the prevention and control of the landslide.