Initiation Mechanism Of Mine Debris Flow Andmethodology For Mitigation And Prevention

In some hilly and mountainous areas with fragile ecological environment,steep terrain and loose rock formations,large-scale concentrated exploitation of mine resources has provided a large amount of loose solids for the formation of debris flows.Mining waste rock slag has become the main source of material,while increasing the slope of the ground.The non-debris flow ditch has evolved into a debris flow ditch.The mudslide-prone areas have been transformed into areas prone to mudslides and a new debris flow-slag-type debris flow has formed.In this study,the gold mine area in the mine-prone area of the Xiaoqinling mine was selected as the research object.The field survey,indoor model test and numerical model simulation were used to investigate the geological environment conditions,debris flow development types and spatial distribution characteristics of debris flow in the area.The critical conditions and mechanism for starting the slag-type debris flow were experimentally analyzed,and the risk assessment maps for the debris flow ditch in the study area were completed,and the preliminary prevention and control suggestions were finally proposed.The main conclusions obtained were as follows:(1)From the aspects of slope surface and channel topography,debris,extreme rainfall and other aspects,the background of debris flow in Daxiyu drainage basin in Shaoguan was analyzed.The major sources of debris flow in Daxiyu channel are collapse accumulations,artificial waste,alluvium,debris flow.The outbreak was mainly caused by water conditions such as heavy rainfall.(2)Using the scale effect to design test tanks,using equal scaling to match model sand,controlling three main variables(bottom slope,grain grading,and discharge flow)to test,the model test results show that the larger the bed slope and the granularity The finer the distribution,the smaller the critical flow rate at which the debris flow starts.(3)A two-dimensional hydrodynamic model was used to simulate the hydrodynamic process of flooding in the Dashixiyu watershed.Stability analysis of debris flow debris flow shows that the start of coarse-grained slag debris flow is mainly related to unit flow shear force,channel slope and slag size distribution.Under similar particle size distribution conditions,the steeper the channel,the greater the flow velocity of the water,the easier it is to form a debris flow.(4)Based on comprehensive source and hydrology factors,suggestions on the prevention of mudslide initiation in Dashixi were put forward.It is recommended to use lead cage slag to treat dangerous slag with pervious solid slag in order to enhance its impact resistance and reduce the risk of mudslides;Debris flow prevention program.