Experimental Study On Rockfall Migration Ratio Under Cross Slope Condition

Rockfall is a kind of gravity-driven rapid,highly random,high-energy disaster.The long-term existence of falling rocks poses a greater threat to human production and life.This paper studies the rockfall migration ratio under different influence factors through model tests.Taking the cross slope gradient,longitudinal slope gradient,shape and size of rockfall,release height and slope pavement as variables,the model test of offset ratio is designed and studied.The influence of these factors on the distribution of falling point,discrete interval and offset ratio of one-way cross slope are analyzed.At the same time,it is determined based on orthogonal testing to determine the sequence of influence on single horizontal slope offset ratio and the most unfavorable level combination.The main research contents and results of this paper are as follows:(1)Release height,quality of falling rock,slope of longitudinal slope and slope of transverse slope are the main factors affecting the distribution of stopping point of falling rock.With the increase of release height,the distribution of stop point is farther away from the foot of slope;the greater the quality of falling stone,the more uniform the distribution of stop point along both sides of center line;with the increase of transverse slope,the stop point is closer to longitudinal slope.With the change of rockfall size and slope pavement,there is no obvious law on the distribution of rockfall stop points.(2)The offset ratio of the unidirectional cross-slope rock falls,with the increase of the release height,but the value of the offset ratio has a maximum value;the offset ratio increases with the increase of the rock mass,but it is also affected by the shape of the rock;The deviation ratio is positively correlated with the slope of the transverse slope,When the slope rises from 15° to 45°,The rockfall offset ratio with 95% probability increases from 1.29 to 3.80,The increase was 194.57 per cent;And,The statistical mean of all rockfall offsets is 1.02,Of which 95% of the corresponding rockfall offset values are less than 2.3,Therefore,when the horizontal slope,the longitudinal slope is in the range 15° to 45°,It is suggested that the offset ratio of falling stone is 2.3.(3)The slope of longitudinal slope,slope of transverse slope,release height,shape and quality of falling rock are the main factors affecting the return rate of falling rock.With the increase of release height,the return rate of falling stone on symmetrical transverse slope decreases gradually;with the increase of aspect ratio,the return rate increases;with the increase of quality grade,the return rate decreases gradually;with the increase of recovery coefficient of slope pavement,the return rate decreases gradually.(4)The main influencing factors are release height,quality of falling rock,slope of longitudinal slope and slope of transverse slope.With the increase of release height,the deviation ratio increases first and then decreases;with the increase of falling quality,the deviation ratio increases;with the increase of slope recovery coefficient,the deviation ratio increases;It is proportional to the slope of longitudinal slope and transverse slope.With the change of falling stone shape,there is no obvious change law of the deviation ratio of falling stone.(5)Based on the orthogonal test,the order of influence of each factor on the ratio of falling stone is obtained,which is as follows: horizontal slope,slope paving,longitudinal slope,release height,falling stone quality,falling stone shape.Therefore,in practical application,special attention should be paid to the influence of cross slope on the rockfall migration ratio.