Study On Deformation Evolution Law Of Bedding Rock Slop

With the rapid development of open-pit mining technology and the construction of a number of modern large open-pit mines,the safety of engineering slopes has been greatly improved,but there are still great safety hazards.In recent years,accidents such as slope collapse and landslide have occurred frequently,and the bedding slope is the most harmful type of landslide.Therefore,the deformation evolution law of bedding rock slope is of great significance to slope engineering.Based on the engineering background of limestone open-pit slope for building stone in Dalanchi,Suijiang County,this paper studies the influence of control parameters on slope deformation characteristics in layered slope,and analyzes the sensitivity of slope control parameters to slope stability.The discrete element strength reduction method based on cusp catastrophe theory is used to summarize the deformation evolution process of bedding rock slope,and the prediction model of safety factor of bedding rock slope is proposed.The sensitivity partition is carried out for the slope with consistent failure characteristics,which provides technical reference for the selection of monitoring points in engineering.The main work and research results are as follows :(1)The field survey of the slope of the Dalanchi mine was carried out,and the rock mass structure of the mine was understood by using the detailed line observation method and the borehole imaging technology method.Through the in-situ direct shear test and the indoor rock mechanics test,the rock mechanics parameters and structural plane parameters of the engineering slope were obtained.According to the different occurrences of the slope,the slope is divided into four regions : the upper,middle,lower east and lower west,of which the upper,middle and lower east are bedding structures.(2)Based on the mechanical parameters of the slope rock mass of the project,the effects of seven control parameters(structural plane spacing d,structural plane dip angle θ,structural plane cohesion C,structural plane internal friction angle φ,slope angle α,slope height H,structural plane inclination β1)on the deformation characteristics of the slope were studied.The results show that H,C,and d have little influence on the deformation characteristics,and θ,φ,and α have a greater influence on the deformation characteristics.The correlation coefficient of each factor to slope stability is analyzed,and the sensitivity of each factor to slope stability is ranked from high to low as α > H > φ > d > C > θ.Slope angle and slope height are negatively correlated with slope stability,while other factors are positively correlated.The tendency of structural plane is highly sensitive to the location of maximum displacement of slope,among which the Y-axis direction is the most significant,and the X-axis direction has the least correlation.(3)The discrete element strength reduction method based on cusp catastrophe theory is used to analyze the deformation evolution process of bedding rock slopes under different occurrences,and the deformation and failure characteristics of various slopes in different deformation evolution stages are summarized.The results are as follows: 1)When the slope angle is 20° and 30°,the deformation evolution process is similar,which is classified as a gentle inclined slope.When the slope angle is 40°,50°and 60°,the deformation evolution process is similar,which is classified as a medium inclined slope.When the slope angle is 70° and 80°,the deformation evolution process is similar,which is classified as a steep inclined slope.2)The deformation evolution law of various slopes with different slope angles is as follows: In the deformation stage,the gentle slope is mostly manifested as settlement deformation,the medium slope is mostly manifested as sliding deformation,and the steep slope is mostly manifested as crack deformation.In the failure stage,the gentle inclined slope is mostly manifested as slope toe slip failure,the medium inclined slope is mostly manifested as slope top slip failure,and the steep inclined slope is mostly manifested as upper edge tensile failure.In the stage of continuous movement after failure,the gentle inclined slope is mostly characterized by lower edge uplift and overall settlement,the medium inclined slope is mostly characterized by continuous sliding failure,and the steep inclined slope is mostly characterized by buckling failure.3)The deformation evolution law of different spatial positions between the structural plane and the free surface of the slope is as follows: In the deformation stage,under different inclinations,cracks and settlement deformation occur when α<θ,and sliding deformation occurs when α=θ andα>θ.In the failure stage,under different inclinations,α<θ mostly occurs toe slip failure and flip failure,and α=θ and α>θ mostly occur toe slip failure.In the stage of continuous movement after failure,the lower edge uplift and the upper edge tensile failure occur mostly in α<θ,the buckling failure occurs mostly in α=θ(when the inclination angle is greater than 10°,the buckling occurs on one side and the slope top sliding occurs on one side),and the continuous sliding failure occurs mostly in α>θ.(4)The multiple linear regression analysis method is used to linearly fit the safety factors of 224 slopes.Taking the inclination angle of structural plane,the inclination angle of structural plane and the slope angle as independent variables,a slope stability prediction model that can calculate the safety factor of bedding rock slope is established.By using the fuzzy recognition method,combined with the deformation evolution law,the sensitivity zoning of the slope is carried out,and the deformation areas of various slopes are divided into extremely sensitive(A1),sensitive(A2),general(A3)and insensitive(A4).(5)Using the summary law and prediction model,the possible failure location of the engineering slope and the characteristics of each stage of deformation evolution are predicted.Combined with the slope stability prediction model,the average safety factor of the slope is 2.89.Combined with the sensitivity partition,the optimization suggestions for the layout of the displacement monitoring points of the engineering slope are proposed.