| Panzhihua-Xichang area stores a large amount of vanadium-titanium magnetite.In the past three decades,Panzhihua Steel Company has used blast furnace smelting technology to use vanadium-titanium magnetite,cosolvent and gangue as raw materials to refine raw iron by reduction reaction.The slag is then discharged from the blast furnace in the form of an accessory.According to statistics,Panzhihua Iron and Steel Co.,Ltd.produced nearly 60 million tons of blast furnace slag,of which about 37 million tons of blast furnace slag was discarded in West Slag-yard,forming a large accumulation slope of about 1600 meters wide and a height of more than 100meters.The scale of the accumulation slope is large,the surface blast furnace slag is loose,close to the Jinsha River,once it is deformed or unstable,it will have a major impact on the life and property safety of the Jinsha River waters and surrounding people.Therefore,it is of great engineering significance to study on the physical and mechanical properties of the blast furnace slag and the slope stability of West Slag-yard in Panzhihua.This paper analyzes the engineering geological characteristics of the West Slag-yard slope in Panzhihua through field geological investigation and aerial photography of the drone,and summarizes the structural characteristics,source and formation reasons of blast furnace slag.Through a series of laboratory tests,summarized the mineral composition,microstructure characteristics,particle size characteristics,particle shape characteristics,density and moisture content,specific gravity characteristics,compaction characteristics,seepage properties,strength characteristics and variation laws of blast furnace slag of West Slag-yard in Panzhihua;According to the conclusions,using engineering geology analysis method,numerical analysis method of the Geostudio software and numerical analysis method of the particle flow to study on the slope stability,results and understanding are as follows(1)The slope of West Slag-yard is mainly composed of loose blast furnace slag and Hot-melt blast furnace slag.The loose blast furnace slag is granular and it located at the front edge of the slope.Its front part is adjacent to the retaining wall along the river,and the rear part is adjacent to the Hot-melt blast furnace slag;There are following four structural forms of the Hot-melt blast furnace slag in the slope:massive cementation morphology,stalactite morphology,overhead structure morphology,and flow pattern structure.(2)The analysis result of X-ray diffraction test and electron microscopy test showed that the main mineral contents of the two kinds of blast furnace slag were different.The main mineral components were diopside,perovskite,diopside,spinel,Bayi stone and heavy titanium.Magnesium oxide;the surface of the loose blast furnace slag is porous,and the surface of the Hot-melt blast furnace slag is mostly a grid-like vitreous crystal-inserted structure.(3)Through the analysis of particle size characteristics test and particle shape characteristics test,the coarse particle granule content of blast furnace slag of West Slag-yard is more than 87%,the gradation is poor,and the lower the slope position,the larger the coarse granule content of the loose blast furnace slag;the axis of loose blast furnace slag The axial coefficient of the loose blast furnace slag K_A is smaller,the massive characteristics are more obvious,and the degree of smoothness is higher;the angularity coefficient of the Hot-melt blast furnace slag A~P is larger,and the particle contour is more irregular,sharper and more angular.(4)Through the analysis of permeability test and compaction test,the permeability coefficient of blast furnace slag of West Slag-yard is relatively large,ranging from 1.01 to 12.96 cm/s.When the fine particle content is less than 30%,the permeability coefficient is more affected;Keep the moisture content constant in the sample,if the fine particle content is 12%,the dry density of the blast furnace slag is the largest.If the fine particle content exceeds 12%,the dry density will decrease continuously;when the fine particle content of the sample is constant,if the water content increases,the dry density is increased first and then decreased.(5)The results of strength characteristics of loose blast furnace slag show that:(a)The strength parameter span is large,C=2.26?181.08kPa,?=4.48?56.72°.(b)When the fine particle content changes in the interval[30,40],the bite force C decreases sharply.When the fine particle content exceeds 30%,the bite force C fluctuates less with the change of water content.(c)When the water content is 1.4%,the internal friction angle?fluctuates less with the change of the fine particle content,when the water content exceeds 6%,the fine particle content changes in the interval[30,40],and the internal friction angle?decreases sharply.(6)The results of strength characteristics of Hot-melt blast furnace show that:(a)The bite force C and internal friction angle?are both large,C=188.39?438.44kPa,?=36.07?43.92°.(b)The internal friction angle?does not change much with the increase of the amount of cement content,and the bite force C is positively correlated with the cement content.(c)Water addition will reduce the bite force C and internal friction angle?.(7)Analysis and calculation results of slope stability.(a)In the engineering geology analysis results,the overall stability of the Hot-melt blast furnace slag layer is good;the loose blast furnace slag layer is in a state of extreme equilibrium under natural conditions,and it is partially unstable under the condition of rising rainfall and river water level;the overall stability of the retaining wall is good.There are no obvious signs of deformation.(b)The result of limit equilibrium analysis show that the slope stability coefficient range is 1.054?1.101,it is in a basically stable state.(c)In the particle flow analysis results,under the condition of low water level of 990m,the overall stability of the slope is better,the displacement of the retaining wall is 0.014m;under the condition of high water level of 1005m,the local stability of the bottom of the slope is slightly poor,and the displacement of the retaining wall is 0.016m;under the condition of 1010m flood level,the overall stability of the slope is reduced,and the displacement of the retaining wall is 0.012m. |
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