| Based on the science and technology demonstration project "Research on dynamic stability evaluation method and comprehensive safety control technology of highway spoil ground in mountainous area" of Yunnan Provincial Department of transportation,this paper takes hundreds of spoil ground in Yunnan Province as the research object,and uses the methods of data collection,field investigation,indoor and outdoor test,theoretical analysis and numerical simulation to analyze the physical and mechanical properties and slope safety of spoil The results are as follows:(1)Field investigation and numerical simulation of particle flow reveal the movement and sorting behavior of the waste slag,resulting in the obvious accumulation and zonation characteristics of horizontal horizon and parallel horizon along the slope.The upper slope is gentle,mainly with fine particles,fully filled;the middle slope is steep,mainly with medium and fine particles;the lower slope is gentle,mainly with medium and coarse particles,rare fine particles,large porosity.(2)According to the physical and mechanical tests of 50 mountain expressway waste disposal sites in the study area,it is found that the natural density of waste mainly ranges from 1.65 to 1.95 The results show that the slag has loose structure and large porosity;the natural angle of repose is mainly concentrated in the range of 36° to 40° which accounts for 68%of the total amount of statistics;the particle size composition of the waste slag can be roughly divided into four dimensions,and the particle size range is generally large,with medium and coarse gravel as the main particle size composition,almost without fine particles,and there is almost no cementation between the waste slag.(3)By introducing the coarse-fine ratio K,the waste slag can be divided into three types:fine waste slag,K<0.5,natural angle of repose:5≤35°;mixed waste slag,0.5<K<1.0,36 °<natural angle of repose<40°;coarse waste slag,1.0 ≤ K,41 ° ≤natural angle of repose.With the increase of coarse particle content,the natural angle of repose first increases and then tends to be flat,and its sensitivity gradually decreases.(4)The common diseases of waste dump in Mountainous Expressway mainly include bottom heave at the front edge of waste dump slope,lateral sliding extrusion deformation,local deformation cracks,soil erosion caused by slope erosion,main structure damage and failure,overall instability and slope failure,etc.The instability failure revealed by the finite element numerical simulation is mainly manifested as the lower seat at the top of the slope,the bottom bulge at the front edge of the toe of the slope,the initial formation of the slip surface from the toe of the slope and gradually extending to the interior of the slope,which is a dynamic development process.(5)Based on the cohesionless characteristics of highway spoil in mountainous area,the calculation formula of safety factor in cohesionless soil slope is introduced into the quantitative evaluation of slope stability of spoil ground.Through simple natural angle of repose measurement and slope angle measurement,the convenient quantitative evaluation of highway spoil ground mainly composed of medium and coarse particles can be realized.(6)A comprehensive safety control technology system for the waste dump of Expressway in mountainous area is established,which includes the control of the slope rate of waste slope shaping,the control of the slope type with wide steps in the middle,the stacking control of reasonable planning of the stacking sequence,the control of the supporting facilities of the main structure and the control of safety management.Figure 91 table 39 reference 98... |
