Study On The Accumulation Character Of Granular Slope And The Evolution Mechanism Of Surficial Failure

The granular slope has the characteristics of wide distribution,poor self-stability,strong recurrence and high sudden occurrence.The infrastructure construction in mountain region,the safety of road pedestrians and the safe operation of transportation are seriously affected by the surficial failure of granular slopes.The development and accumulation characteristics of granular slope,the relationship between recharge and surficial failure in cuttings source area,the degree of activity and evolution law of surficial failure are the key issues and difficulties in early identification and risk assessment of this kind of geological hazards.Therefore,it is with great practical significance to study granular slope.The granular slope restricted by retaining wall was chosen for this study.Based on the geological survey and literature review,the types,formation conditions and developmental evolution characteristics of granular slopes are expounded,and the general geological model was generalized.The indoor physical model test was used to analyze the influence of particle fractal dimension,slope size and particle size on the surficial failure law and evolution mechanism.The main contents and results of this thesis include:1.The slope forming process of the granular slope can be divided into the post-stacking stage of the retaining wall,the inclined plate accumulation stage,the slope growth stage and the slope forming stage.There are two kinds of migration modes of particles on the slope:jumping and rolling.During the process of accumulation,the coarse particles are easy to accumulate in the lower part of the slope,the middle particles are accumulated in the middle and upper part of the slope,and the fine particles are more likely to accumulate in the upper part of the slope.With the increase of particle size,the migration distance on the slope will become longer.2.There is periodic large-scale slip on granular slope with different fractal dimensions.The variation of slope slip is mainly related to fractal dimension,slope scale and particle size.With the increase of fractal dimension,the surficial failure is more likely to occur,and the mass of surficial failure becomes smaller.With the increase of slope scale,the mass of surficial failure will also be increased,while,the potential of slope surface will be decreased.With the increase of particle size,the mass of surficial failure become bigger,while,the potential of slope surface will be decreased.3.The evolution of shallow slip on granular slope can be summed up as the evolution law between small scale slip and whole shallow slip periodically.Among them,the scale and frequency of slope slip with fractal dimension D=1.5 and 1.9 show power law distribution,and there is self-organization criticality.The shallow slip failure of slope can be divided into small-scale slip and whole slip.The small-scale slip is mainly groove slip and finger slip,and the particle ratio is the same as the original ratio.The whole slip has the progressive type failure and the traction type failure,the particle proportion is mainly coarse and medium particles.