Analysis Of Failure Mode And Stability Influencing Factors Of Anti-tilt High Slope

Anti-dip slope,as a more common type of slope in the slope of water conservancy projects,has been developing in the direction of "high,large and difficult" in recent years,which has caused the problem of anti-dip high slope to be prominent and lost stability occurs frequently.In addition,there are many factors influencing the stability of anti-tilt slopes.At present,most researches stay in simple qualitative descriptions of correlations,and there are few in-depth analysis and discussion on the causes of correlations.The failure mechanism and stability of high slopes under multiple factors sexual analysis is even less.Therefore,on the basis of summarizing previous studies,this paper relies on the Jinping Ⅰ left bank anti-tilt high slope as the prototype object,and completed 49 orthogonal designs from four aspects: slope height,slope angle,rock layer inclination angle and layer thickness generalize the slope model,and develop the sensitivity analysis of the factors that affect the stability and failure mode of the anti-tilt high slope through the safety factor and the acoustic emission parameters;then based on the principle of centrifugal loading,the finite element analysis software RFPA 3D-Centrifugal is used to 49 generalized slope model was used for numerical simulation analysis to explore the change patterns of the failure mode,stress field,displacement field and acoustic emission field of anti-tilt high slopes at different slope heights and slope angles;finally,combining typical anti-tilt high slopes— Jinping Ⅰ left bank slope is an engineering example.Based on the analysis of the aforementioned four factors,the failure mode and stability influencing factors of the actual anti-tilt high slope are evaluated around six typical sections of the project.The specific research content and conclusions are as follows:(1)Summarize the research status of anti-tilt slopes in the past 30 years,summarize from the aspects of anti-tilt slope dumping failure mechanism,factors affecting dumping failure and stability analysis methods of anti-tilt slopes,and finally draw the main failure modes of anti-tilt high slopes are pull failure,slip failure and breakage failure.It is determined that the centrifugal loading finite element method can better describe the failure process of anti-tilt slopes.(2)The servo rigidity testing machine(MTS815)and the Realistic Failure Process Analysis System were used to study the failure mechanism and mechanical characteristics of Jinping marble under uniaxial compression,and found that the marble was compressed under uniaxial compression the deformation process in the state includes four stages of initial compaction,elastic deformation,plastic deformation and residual deformation.The maximum compressive strength is 168.4MPa and 161 MPa respectively,and the failure mode is mainly shear failure;at the same time,it is determined according to the RFPA mesomechanical parameters Method,based on laboratory experiments to obtain more practical numerical simulation parameters.(3)Based on the four factors that affect the stability of the anti-tilt slope,such as slope height,slope angle,rock layer inclination angle and layer thickness,orthogonal test design was carried out,and 49 slope models were generalized to develop the sensitivity analysis of the four factors.The slope safety factor determines that the slope height and slope angle are completely significant,the slope angle is completely significant to the number of acoustic emissions and the cumulative number of acoustic emissions of the slope,and the sensitivity of the four factors to the slope safety factor is slope height > slope angle > inclination angle > layer thickness,the order of sensitivity to the number of acoustic emissions and cumulative number of acoustic emissions is slope angle > layer thickness > slope height > inclination.According to the sensitivity analysis results,it is finally determined that the slope height and slope angle are the main factors affecting the stability of the anti-tilt high slope.Therefore,the slope height and slope angle are selected as the objects for the key analysis of subsequent numerical simulation.(4)Relying on the principle of centrifugal loading,using the real rupture process analysis system RFPA3D-Centrifugal,the 49 generalized slope models are discussed in terms of failure mode,stress field,displacement field and acoustic emission field.As the slope angle increases,the direction of the maximum principal stress and horizontal displacement of the anti-dip high slope change,and the shear stress along the plane gradually decreases and the normal stress perpendicular to the plane gradually increases.When the slope angle is less than 50 °,the failure mode of the slope is deep cracking.When the slope angle is greater than 50 °,the failure mode of the slope is shallow sliding failure.Therefore,the excavation design of the high slope the excavation slope angle should not exceed 50 °,and the excavation slope ratio should not be greater than 1: 1.19.As the slope height increases,the downward component of the anti-tilt high slope along the plane and the normal component of the normal layer increase by a multiple,and the safety factor of the slope decreases sharply.Therefore,in the design and construction of the anti-tilt high slope,certain slope reduction and load reduction can improve the stability of the slope without changing the failure mode of the slope.(5)Based on the example of Jinping Ⅰ left bank anti-tilt high slope project,the actual high slope failure mode and stability analysis are carried out,and it is found that slope height and slope angle are still the main factors affecting the high slope failure mode,and its change law in line with the above generalized slope conclusion;due to the fact that there are many combinations of weak structural planes and other sliding surfaces in actual engineering slopes,six typical sections are selected for analysis,and it is pointed out that when there are weak structural planes,their damage and stability to the slope The analysis has a significant impact.The failure mechanism of the left bank slope is mainly to form a set of wedge-shaped slip planes with the vein X and the stratum boundary to cut off the f2 fault,so that the outer rock mass of f5 slides out along the slip surface and the deep part of the f5 and f8 faults.The intersection and the bottom stratum boundary form a combined slip surface that shears the f2 fault and causes the f5 outer rock mass to slide out along the slip surface.