| The dangerous rock is a common geological hazard type in the three gorges reservoir area.Three gorges reservoir area of the high and steep rocky base under the influence of water level fluctuation,the most dangerous rock base are 145 meters under water,including rock due to dry-wet circulation role,dissolution and precipitation in a variety of effects of abrasion function classification,rising to the degradation of rock mass and at the same time also contributed to the development of unloading zones,the three gorges reservoir area has formed the high dangerous rock mass.This kind of dangerous rock mass has many characteristics such as wide distribution,poor stability and serious disaster.In this paper,SRT single-rope lifting technique is used for fine investigation of rock climbing,and new methods such as high-definition camera,three-dimensional tilting camera and multi-beam underwater survey are introduced to ascertain the internal structure characteristics of dangerous rock.According to the geological environment characteristics of dangerous rock area,the relevant knowledge and theory of topography,engineering geology and geological structure are combined.By successive analysis,the key blocks of group chain dangerous rock are found,and the main controlling factors are analyzed.The failure mechanism and stability of group chain dangerous rock are studied through qualitative analysis,quantitative calculation and numerical simulation.The main forms of failure of key blocks of high and steep dangerous rock wading in reservoir area are put forward,and the corresponding prevention measures and suggestions are provided for disaster prevention and risk reduction of dangerous rock disasters.This paper takes the dangerous rock belt of Huangyan cave in Wuxia gorge as the research objec:(1)The dangerous rock is located in the high and steep gorge area.The geological environment is complex.The unloading cracks on the river face spread out and extend to the river surface and the rock mass is broken.How to analyze the degree of rock mass degradation and breakage in the depression zone,how to investigate the cliff-cliff cracks,and how to find out the situation of the dangerous rock foundation under thewater level of 145 m are the problems.In addition to traditional exploration methods such as surveying,sketching,grooving,geophysical prospecting and drilling,this paper also successfully uses SRT single-rope lifting technology for fine rock climbing investigation,,creatively,introduces,multi-beam,underwater,surveying,three-dimensional laser scanning,three-dimensional tilt photography,high-definition photography in horizontal boreholes,rock and mineral identification and other methods,and finds out the interior of dangerous rocks.The basic characteristics of the dangerous rock include scope,scale,nature and elements.(2)In this paper,through the analysis of the structural characteristics of dangerous rock mass,the deformation and failure characteristics of dangerous rock zone,the stability of each block is analyzed one by one,the key block of the group chain dangerous rock is found,and the main controlling factors of the key block are analyzed.And stability.(3)Based on the analysis of the failure characteristics and mineral composition of the dangerous rock mass,the main failure forms of the key blocks in the high and steep dangerous rock mass are put forward: dissolution,unloading tension crack,water level fluctuation zone erosion,rock mass deterioration in the depression zone.(4)Combining with the study of engineering geological environment conditions and deformation and failure mechanism of dangerous rock,in order to prevent the danger from happening and take precautions against it,this paper puts forward the preventive measures of "emergency risk control and risk control design". |
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